def test_example(self):
ref = ants.image_read(ants.get_ants_data('r16'))
ref = ants.resample_image(ref, (50, 50), 1, 0)
ref = ants.iMath(ref, 'Normalize')
mi = ants.image_read(ants.get_ants_data('r27'))
mi2 = ants.image_read(ants.get_ants_data('r30'))
mi3 = ants.image_read(ants.get_ants_data('r62'))
mi4 = ants.image_read(ants.get_ants_data('r64'))
mi5 = ants.image_read(ants.get_ants_data('r85'))
refmask = ants.get_mask(ref)
refmask = ants.iMath(refmask, 'ME', 2) # just to speed things up
ilist = [mi, mi2, mi3, mi4, mi5]
seglist = [None] * len(ilist)
for i in range(len(ilist)):
ilist[i] = ants.iMath(ilist[i], 'Normalize')
mytx = ants.registration(fixed=ref,
moving=ilist[i],
typeofTransform=('Affine'))
mywarpedimage = ants.apply_transforms(
fixed=ref,
moving=ilist[i],
transformlist=mytx['fwdtransforms'])
ilist[i] = mywarpedimage
seg = ants.threshold_image(ilist[i], 'Otsu', 3)
seglist[i] = (seg) + ants.threshold_image(seg, 1, 3).morphology(
operation='dilate', radius=3)
r = 2
pp = ants.joint_label_fusion(ref,
refmask,
ilist,
r_search=2,
label_list=seglist,
rad=[r] * ref.dimension)
pp = ants.joint_label_fusion(ref, refmask, ilist, r_search=2, rad=2)
def test_vol_example(self):
ch2i = ants.image_read(ants.get_ants_data("mni"))
ch2seg = ants.threshold_image(ch2i, "Otsu", 3)
wm = ants.threshold_image(ch2seg, 3, 3)
kimg = ants.weingarten_image_curvature(ch2i, 1.5).smooth_image(1)
rp = [(90, 180, 90), (90, 180, 270), (90, 180, 180)]
filename = mktemp(suffix='.png')
result = ants.vol(wm, [kimg],
quantlimits=(0.01, 0.99),
filename=filename)
def test_surf_example(self):
ch2i = ants.image_read(ants.get_ants_data("ch2"))
ch2seg = ants.threshold_image(ch2i, "Otsu", 3)
wm = ants.threshold_image(ch2seg, 3, 3)
wm2 = wm.smooth_image(1).threshold_image(0.5, 1e15)
kimg = ants.weingarten_image_curvature(ch2i, 1.5).smooth_image(1)
wmz = wm2.iMath("MD", 3)
rp = [(90, 180, 90), (90, 180, 270), (90, 180, 180)]
filename = mktemp(suffix='.png')
ants.surf(x=wm2,
y=[kimg],
z=[wmz],
inflation_factor=255,
overlay_limits=(-0.3, 0.3),
verbose=True,
rotation_params=rp,
filename=filename)
def __brain_extraction(self):
# https://antsx.github.io/ANTsPyNet/docs/build/html/utilities.html#applications
if self._modality == "t1":
image = self._t1_n4
elif self._modality == "t2":
image = self._t2_n4
else:
sys.exit("invalid contrast specified for brain extraction")
prob = brain_extraction(image, modality=self._modality)
# mask can be obtained as:
mask = ants.threshold_image(prob,
low_thresh=0.5,
high_thresh=1.0,
inval=1,
outval=0,
binary=True)
return mask
def test_example(self):
fi = ants.image_read(ants.get_ants_data('r16'))
seg = ants.kmeans_segmentation(fi, 3)
mask = ants.threshold_image(seg['segmentation'], 1, 1e15)
priorseg = ants.prior_based_segmentation(fi, seg['probabilityimages'],
mask, 0.25, 0.1, 3)
def desikan_killiany_tourville_labeling(t1,
do_preprocessing=True,
return_probability_images=False,
do_lobar_parcellation=False,
antsxnet_cache_directory=None,
verbose=False):
"""
Cortical and deep gray matter labeling using Desikan-Killiany-Tourville
Perform DKT labeling using deep learning
The labeling is as follows:
Inner labels:
Label 0: background
Label 4: left lateral ventricle
Label 5: left inferior lateral ventricle
Label 6: left cerebellem exterior
Label 7: left cerebellum white matter
Label 10: left thalamus proper
Label 11: left caudate
Label 12: left putamen
Label 13: left pallidium
Label 15: 4th ventricle
Label 16: brain stem
Label 17: left hippocampus
Label 18: left amygdala
Label 24: CSF
Label 25: left lesion
Label 26: left accumbens area
Label 28: left ventral DC
Label 30: left vessel
Label 43: right lateral ventricle
Label 44: right inferior lateral ventricle
Label 45: right cerebellum exterior
Label 46: right cerebellum white matter
Label 49: right thalamus proper
Label 50: right caudate
Label 51: right putamen
Label 52: right palladium
Label 53: right hippocampus
Label 54: right amygdala
Label 57: right lesion
Label 58: right accumbens area
Label 60: right ventral DC
Label 62: right vessel
Label 72: 5th ventricle
Label 85: optic chasm
Label 91: left basal forebrain
Label 92: right basal forebrain
Label 630: cerebellar vermal lobules I-V
Label 631: cerebellar vermal lobules VI-VII
Label 632: cerebellar vermal lobules VIII-X
Outer labels:
Label 1002: left caudal anterior cingulate
Label 1003: left caudal middle frontal
Label 1005: left cuneus
Label 1006: left entorhinal
Label 1007: left fusiform
Label 1008: left inferior parietal
Label 1009: left inferior temporal
Label 1010: left isthmus cingulate
Label 1011: left lateral occipital
Label 1012: left lateral orbitofrontal
Label 1013: left lingual
Label 1014: left medial orbitofrontal
Label 1015: left middle temporal
Label 1016: left parahippocampal
Label 1017: left paracentral
Label 1018: left pars opercularis
Label 1019: left pars orbitalis
Label 1020: left pars triangularis
Label 1021: left pericalcarine
Label 1022: left postcentral
Label 1023: left posterior cingulate
Label 1024: left precentral
Label 1025: left precuneus
Label 1026: left rostral anterior cingulate
Label 1027: left rostral middle frontal
Label 1028: left superior frontal
Label 1029: left superior parietal
Label 1030: left superior temporal
Label 1031: left supramarginal
Label 1034: left transverse temporal
Label 1035: left insula
Label 2002: right caudal anterior cingulate
Label 2003: right caudal middle frontal
Label 2005: right cuneus
Label 2006: right entorhinal
Label 2007: right fusiform
Label 2008: right inferior parietal
Label 2009: right inferior temporal
Label 2010: right isthmus cingulate
Label 2011: right lateral occipital
Label 2012: right lateral orbitofrontal
Label 2013: right lingual
Label 2014: right medial orbitofrontal
Label 2015: right middle temporal
Label 2016: right parahippocampal
Label 2017: right paracentral
Label 2018: right pars opercularis
Label 2019: right pars orbitalis
Label 2020: right pars triangularis
Label 2021: right pericalcarine
Label 2022: right postcentral
Label 2023: right posterior cingulate
Label 2024: right precentral
Label 2025: right precuneus
Label 2026: right rostral anterior cingulate
Label 2027: right rostral middle frontal
Label 2028: right superior frontal
Label 2029: right superior parietal
Label 2030: right superior temporal
Label 2031: right supramarginal
Label 2034: right transverse temporal
Label 2035: right insula
Performing the lobar parcellation is based on the FreeSurfer division
described here:
See https://surfer.nmr.mgh.harvard.edu/fswiki/CorticalParcellation
Frontal lobe:
Label 1002: left caudal anterior cingulate
Label 1003: left caudal middle frontal
Label 1012: left lateral orbitofrontal
Label 1014: left medial orbitofrontal
Label 1017: left paracentral
Label 1018: left pars opercularis
Label 1019: left pars orbitalis
Label 1020: left pars triangularis
Label 1024: left precentral
Label 1026: left rostral anterior cingulate
Label 1027: left rostral middle frontal
Label 1028: left superior frontal
Label 2002: right caudal anterior cingulate
Label 2003: right caudal middle frontal
Label 2012: right lateral orbitofrontal
Label 2014: right medial orbitofrontal
Label 2017: right paracentral
Label 2018: right pars opercularis
Label 2019: right pars orbitalis
Label 2020: right pars triangularis
Label 2024: right precentral
Label 2026: right rostral anterior cingulate
Label 2027: right rostral middle frontal
Label 2028: right superior frontal
Parietal:
Label 1008: left inferior parietal
Label 1010: left isthmus cingulate
Label 1022: left postcentral
Label 1023: left posterior cingulate
Label 1025: left precuneus
Label 1029: left superior parietal
Label 1031: left supramarginal
Label 2008: right inferior parietal
Label 2010: right isthmus cingulate
Label 2022: right postcentral
Label 2023: right posterior cingulate
Label 2025: right precuneus
Label 2029: right superior parietal
Label 2031: right supramarginal
Temporal:
Label 1006: left entorhinal
Label 1007: left fusiform
Label 1009: left inferior temporal
Label 1015: left middle temporal
Label 1016: left parahippocampal
Label 1030: left superior temporal
Label 1034: left transverse temporal
Label 2006: right entorhinal
Label 2007: right fusiform
Label 2009: right inferior temporal
Label 2015: right middle temporal
Label 2016: right parahippocampal
Label 2030: right superior temporal
Label 2034: right transverse temporal
Occipital:
Label 1005: left cuneus
Label 1011: left lateral occipital
Label 1013: left lingual
Label 1021: left pericalcarine
Label 2005: right cuneus
Label 2011: right lateral occipital
Label 2013: right lingual
Label 2021: right pericalcarine
Other outer labels:
Label 1035: left insula
Label 2035: right insula
Preprocessing on the training data consisted of:
* n4 bias correction,
* denoising,
* brain extraction, and
* affine registration to MNI.
The input T1 should undergo the same steps. If the input T1 is the raw
T1, these steps can be performed by the internal preprocessing, i.e. set
do_preprocessing = True
Arguments
---------
t1 : ANTsImage
raw or preprocessed 3-D T1-weighted brain image.
do_preprocessing : boolean
See description above.
return_probability_images : boolean
Whether to return the two sets of probability images for the inner and outer
labels.
do_lobar_parcellation : boolean
Perform lobar parcellation (also divided by hemisphere).
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
List consisting of the segmentation image and probability images for
each label.
Example
-------
>>> image = ants.image_read("t1.nii.gz")
>>> dkt = desikan_killiany_tourville_labeling(image)
"""
from ..architectures import create_unet_model_3d
from ..utilities import get_pretrained_network
from ..utilities import get_antsxnet_data
from ..utilities import preprocess_brain_image
from ..utilities import deep_atropos
if t1.dimension != 3:
raise ValueError("Image dimension must be 3.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
template_transform_type = "antsRegistrationSyNQuickRepro[a]"
################################
#
# Preprocess images
#
################################
t1_preprocessed = t1
if do_preprocessing == True:
t1_preprocessing = preprocess_brain_image(
t1,
truncate_intensity=(0.01, 0.99),
brain_extraction_modality="t1",
template="croppedMni152",
template_transform_type=template_transform_type,
do_bias_correction=True,
do_denoising=True,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
t1_preprocessed = t1_preprocessing[
"preprocessed_image"] * t1_preprocessing['brain_mask']
################################
#
# Download spatial priors for outer model
#
################################
spatial_priors_file_name_path = get_antsxnet_data(
"priorDktLabels", antsxnet_cache_directory=antsxnet_cache_directory)
spatial_priors = ants.image_read(spatial_priors_file_name_path)
priors_image_list = ants.ndimage_to_list(spatial_priors)
################################
#
# Build outer model and load weights
#
################################
template_size = (96, 112, 96)
labels = (0, 1002, 1003, *tuple(range(1005, 1032)), 1034, 1035, 2002, 2003,
*tuple(range(2005, 2032)), 2034, 2035)
channel_size = 1 + len(priors_image_list)
unet_model = create_unet_model_3d((*template_size, channel_size),
number_of_outputs=len(labels),
number_of_layers=4,
number_of_filters_at_base_layer=16,
dropout_rate=0.0,
convolution_kernel_size=(3, 3, 3),
deconvolution_kernel_size=(2, 2, 2),
weight_decay=1e-5,
additional_options=("attentionGating"))
weights_file_name = None
weights_file_name = get_pretrained_network(
"dktOuterWithSpatialPriors",
antsxnet_cache_directory=antsxnet_cache_directory)
unet_model.load_weights(weights_file_name)
################################
#
# Do prediction and normalize to native space
#
################################
if verbose == True:
print("Outer model Prediction.")
downsampled_image = ants.resample_image(t1_preprocessed,
template_size,
use_voxels=True,
interp_type=0)
image_array = downsampled_image.numpy()
image_array = (image_array - image_array.mean()) / image_array.std()
batchX = np.zeros((1, *template_size, channel_size))
batchX[0, :, :, :, 0] = image_array
for i in range(len(priors_image_list)):
resampled_prior_image = ants.resample_image(priors_image_list[i],
template_size,
use_voxels=True,
interp_type=0)
batchX[0, :, :, :, i + 1] = resampled_prior_image.numpy()
predicted_data = unet_model.predict(batchX, verbose=verbose)
origin = downsampled_image.origin
spacing = downsampled_image.spacing
direction = downsampled_image.direction
inner_probability_images = list()
for i in range(len(labels)):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[0, :, :, :, i]),
origin=origin, spacing=spacing, direction=direction)
resampled_image = ants.resample_image(probability_image,
t1_preprocessed.shape,
use_voxels=True,
interp_type=0)
if do_preprocessing == True:
inner_probability_images.append(
ants.apply_transforms(
fixed=t1,
moving=resampled_image,
transformlist=t1_preprocessing['template_transforms']
['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose))
else:
inner_probability_images.append(resampled_image)
image_matrix = ants.image_list_to_matrix(inner_probability_images,
t1 * 0 + 1)
segmentation_matrix = np.argmax(image_matrix, axis=0)
segmentation_image = ants.matrix_to_images(
np.expand_dims(segmentation_matrix, axis=0), t1 * 0 + 1)[0]
dkt_label_image = ants.image_clone(segmentation_image)
for i in range(len(labels)):
dkt_label_image[segmentation_image == i] = labels[i]
################################
#
# Build inner model and load weights
#
################################
template_size = (160, 192, 160)
labels = (0, 4, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 18, 24, 26, 28, 30,
43, 44, 45, 46, 49, 50, 51, 52, 53, 54, 58, 60, 91, 92, 630, 631,
632)
unet_model = create_unet_model_3d((*template_size, 1),
number_of_outputs=len(labels),
number_of_layers=4,
number_of_filters_at_base_layer=8,
dropout_rate=0.0,
convolution_kernel_size=(3, 3, 3),
deconvolution_kernel_size=(2, 2, 2),
weight_decay=1e-5,
additional_options=("attentionGating"))
weights_file_name = get_pretrained_network(
"dktInner", antsxnet_cache_directory=antsxnet_cache_directory)
unet_model.load_weights(weights_file_name)
################################
#
# Do prediction and normalize to native space
#
################################
if verbose == True:
print("Prediction.")
cropped_image = ants.crop_indices(t1_preprocessed, (12, 14, 0),
(172, 206, 160))
batchX = np.expand_dims(cropped_image.numpy(), axis=0)
batchX = np.expand_dims(batchX, axis=-1)
batchX = (batchX - batchX.mean()) / batchX.std()
predicted_data = unet_model.predict(batchX, verbose=verbose)
origin = cropped_image.origin
spacing = cropped_image.spacing
direction = cropped_image.direction
outer_probability_images = list()
for i in range(len(labels)):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[0, :, :, :, i]),
origin=origin, spacing=spacing, direction=direction)
if i > 0:
decropped_image = ants.decrop_image(probability_image,
t1_preprocessed * 0)
else:
decropped_image = ants.decrop_image(probability_image,
t1_preprocessed * 0 + 1)
if do_preprocessing == True:
outer_probability_images.append(
ants.apply_transforms(
fixed=t1,
moving=decropped_image,
transformlist=t1_preprocessing['template_transforms']
['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose))
else:
outer_probability_images.append(decropped_image)
image_matrix = ants.image_list_to_matrix(outer_probability_images,
t1 * 0 + 1)
segmentation_matrix = np.argmax(image_matrix, axis=0)
segmentation_image = ants.matrix_to_images(
np.expand_dims(segmentation_matrix, axis=0), t1 * 0 + 1)[0]
################################
#
# Incorporate the inner model results into the final label image.
# Note that we purposely prioritize the inner label results.
#
################################
for i in range(len(labels)):
if labels[i] > 0:
dkt_label_image[segmentation_image == i] = labels[i]
if do_lobar_parcellation:
if verbose == True:
print("Doing lobar parcellation.")
################################
#
# Lobar/hemisphere parcellation
#
################################
# Consolidate lobar cortical labels
if verbose == True:
print(" Consolidating cortical labels.")
frontal_labels = (1002, 1003, 1012, 1014, 1017, 1018, 1019, 1020, 1024,
1026, 1027, 1028, 2002, 2003, 2012, 2014, 2017, 2018,
2019, 2020, 2024, 2026, 2027, 2028)
parietal_labels = (1008, 1010, 1022, 1023, 1025, 1029, 1031, 2008,
2010, 2022, 2023, 2025, 2029, 2031)
temporal_labels = (1006, 1007, 1009, 1015, 1016, 1030, 1034, 2006,
2007, 2009, 2015, 2016, 2030, 2034)
occipital_labels = (1005, 1011, 1013, 1021, 2005, 2011, 2013, 2021)
lobar_labels = list()
lobar_labels.append(frontal_labels)
lobar_labels.append(parietal_labels)
lobar_labels.append(temporal_labels)
lobar_labels.append(occipital_labels)
dkt_lobes = ants.image_clone(dkt_label_image)
dkt_lobes[dkt_lobes < 1000] = 0
for i in range(len(lobar_labels)):
for j in range(len(lobar_labels[i])):
dkt_lobes[dkt_lobes == lobar_labels[i][j]] = i + 1
dkt_lobes[dkt_lobes > len(lobar_labels)] = 0
six_tissue = deep_atropos(
t1_preprocessed,
do_preprocessing=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
atropos_seg = six_tissue['segmentation_image']
if do_preprocessing == True:
atropos_seg = ants.apply_transforms(
fixed=t1,
moving=atropos_seg,
transformlist=t1_preprocessing['template_transforms']
['invtransforms'],
whichtoinvert=[True],
interpolator="genericLabel",
verbose=verbose)
brain_mask = ants.image_clone(atropos_seg)
brain_mask[brain_mask == 1 or brain_mask == 5 or brain_mask == 6] = 0
brain_mask = ants.threshold_image(brain_mask, 0, 0, 0, 1)
lobar_parcellation = ants.iMath(brain_mask,
"PropagateLabelsThroughMask",
brain_mask * dkt_lobes)
lobar_parcellation[atropos_seg == 5] = 5
lobar_parcellation[atropos_seg == 6] = 6
# Do left/right
if verbose == True:
print(" Doing left/right hemispheres.")
left_labels = (*tuple(range(4, 8)), *tuple(range(10, 14)), 17, 18, 25,
26, 28, 30, 91, 1002, 1003, *tuple(range(1005, 1032)),
1034, 1035)
right_labels = (*tuple(range(43, 47)), *tuple(range(49, 55)), 57, 58,
60, 62, 92, 2002, 2003, *tuple(range(2005, 2032)),
2034, 2035)
hemisphere_labels = list()
hemisphere_labels.append(left_labels)
hemisphere_labels.append(right_labels)
dkt_hemispheres = ants.image_clone(dkt_label_image)
for i in range(len(hemisphere_labels)):
for j in range(len(hemisphere_labels[i])):
dkt_hemispheres[dkt_hemispheres == hemisphere_labels[i]
[j]] = i + 1
dkt_hemispheres[dkt_hemispheres > 2] = 0
atropos_brain_mask = ants.threshold_image(atropos_seg, 0, 0, 0, 1)
hemisphere_parcellation = ants.iMath(
atropos_brain_mask, "PropagateLabelsThroughMask",
atropos_brain_mask * dkt_hemispheres)
# The following contains a bug somewhere as only the latter condition is seen.
# Need to fix it.
#
# for i in range(6):
# lobar_parcellation[lobar_parcellation == (i + 1) and hemisphere_parcellation == 2] = 6 + i + 1
hemisphere_parcellation *= ants.threshold_image(
lobar_parcellation, 0, 0, 0, 1)
hemisphere_parcellation[hemisphere_parcellation == 1] = 0
hemisphere_parcellation[hemisphere_parcellation == 2] = 1
hemisphere_parcellation *= 6
lobar_parcellation += hemisphere_parcellation
if return_probability_images == True and do_lobar_parcellation == True:
return_dict = {
'segmentation_image': dkt_label_image,
'lobar_parcellation': lobar_parcellation,
'inner_probability_images': inner_probability_images,
'outer_probability_images': outer_probability_images
}
return (return_dict)
elif return_probability_images == True and do_lobar_parcellation == False:
return_dict = {
'segmentation_image': dkt_label_image,
'inner_probability_images': inner_probability_images,
'outer_probability_images': outer_probability_images
}
return (return_dict)
elif return_probability_images == False and do_lobar_parcellation == True:
return_dict = {
'segmentation_image': dkt_label_image,
'lobar_parcellation': lobar_parcellation
}
return (return_dict)
else:
return (dkt_label_image)
def deep_flash(t1,
t2=None,
do_preprocessing=True,
use_rank_intensity=True,
antsxnet_cache_directory=None,
verbose=False):
"""
Hippocampal/Enthorhinal segmentation using "Deep Flash"
Perform hippocampal/entorhinal segmentation in T1 and T1/T2 images using
labels from Mike Yassa's lab
https://faculty.sites.uci.edu/myassa/
The labeling is as follows:
Label 0 : background
Label 5 : left aLEC
Label 6 : right aLEC
Label 7 : left pMEC
Label 8 : right pMEC
Label 9 : left perirhinal
Label 10: right perirhinal
Label 11: left parahippocampal
Label 12: right parahippocampal
Label 13: left DG/CA2/CA3/CA4
Label 14: right DG/CA2/CA3/CA4
Label 15: left CA1
Label 16: right CA1
Label 17: left subiculum
Label 18: right subiculum
Preprocessing on the training data consisted of:
* n4 bias correction,
* affine registration to the "deep flash" template.
which is performed on the input images if do_preprocessing = True.
Arguments
---------
t1 : ANTsImage
raw or preprocessed 3-D T1-weighted brain image.
t2 : ANTsImage
Optional 3-D T2-weighted brain image. If specified, it is assumed to be
pre-aligned to the t1.
do_preprocessing : boolean
See description above.
use_rank_intensity : boolean
If false, use histogram matching with cropped template ROI. Otherwise,
use a rank intensity transform on the cropped ROI.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
List consisting of the segmentation image and probability images for
each label and foreground.
Example
-------
>>> image = ants.image_read("t1.nii.gz")
>>> flash = deep_flash(image)
"""
from ..architectures import create_unet_model_3d
from ..utilities import get_pretrained_network
from ..utilities import get_antsxnet_data
from ..utilities import brain_extraction
if t1.dimension != 3:
raise ValueError("Image dimension must be 3.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
################################
#
# Options temporarily taken from the user
#
################################
# use_hierarchical_parcellation : boolean
# If True, use u-net model with additional outputs of the medial temporal lobe
# region, hippocampal, and entorhinal/perirhinal/parahippocampal regions. Otherwise
# the only additional output is the medial temporal lobe.
#
# use_contralaterality : boolean
# Use both hemispherical models to also predict the corresponding contralateral
# segmentation and use both sets of priors to produce the results. Mainly used
# for debugging.
use_hierarchical_parcellation = True
use_contralaterality = True
################################
#
# Preprocess images
#
################################
t1_preprocessed = t1
t1_mask = None
t1_preprocessed_flipped = None
t1_template = ants.image_read(
get_antsxnet_data("deepFlashTemplateT1SkullStripped"))
template_transforms = None
if do_preprocessing:
if verbose == True:
print("Preprocessing T1.")
# Brain extraction
probability_mask = brain_extraction(
t1_preprocessed,
modality="t1",
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
t1_mask = ants.threshold_image(probability_mask, 0.5, 1, 1, 0)
t1_preprocessed = t1_preprocessed * t1_mask
# Do bias correction
t1_preprocessed = ants.n4_bias_field_correction(t1_preprocessed,
t1_mask,
shrink_factor=4,
verbose=verbose)
# Warp to template
registration = ants.registration(
fixed=t1_template,
moving=t1_preprocessed,
type_of_transform="antsRegistrationSyNQuickRepro[a]",
verbose=verbose)
template_transforms = dict(fwdtransforms=registration['fwdtransforms'],
invtransforms=registration['invtransforms'])
t1_preprocessed = registration['warpedmovout']
if use_contralaterality:
t1_preprocessed_array = t1_preprocessed.numpy()
t1_preprocessed_array_flipped = np.flip(t1_preprocessed_array, axis=0)
t1_preprocessed_flipped = ants.from_numpy(
t1_preprocessed_array_flipped,
origin=t1_preprocessed.origin,
spacing=t1_preprocessed.spacing,
direction=t1_preprocessed.direction)
t2_preprocessed = t2
t2_preprocessed_flipped = None
t2_template = None
if t2 is not None:
t2_template = ants.image_read(
get_antsxnet_data("deepFlashTemplateT2SkullStripped"))
t2_template = ants.copy_image_info(t1_template, t2_template)
if do_preprocessing:
if verbose == True:
print("Preprocessing T2.")
# Brain extraction
t2_preprocessed = t2_preprocessed * t1_mask
# Do bias correction
t2_preprocessed = ants.n4_bias_field_correction(t2_preprocessed,
t1_mask,
shrink_factor=4,
verbose=verbose)
# Warp to template
t2_preprocessed = ants.apply_transforms(
fixed=t1_template,
moving=t2_preprocessed,
transformlist=template_transforms['fwdtransforms'],
verbose=verbose)
if use_contralaterality:
t2_preprocessed_array = t2_preprocessed.numpy()
t2_preprocessed_array_flipped = np.flip(t2_preprocessed_array,
axis=0)
t2_preprocessed_flipped = ants.from_numpy(
t2_preprocessed_array_flipped,
origin=t2_preprocessed.origin,
spacing=t2_preprocessed.spacing,
direction=t2_preprocessed.direction)
probability_images = list()
labels = (0, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
image_size = (64, 64, 96)
################################
#
# Process left/right in split networks
#
################################
################################
#
# Download spatial priors
#
################################
spatial_priors_file_name_path = get_antsxnet_data(
"deepFlashPriors", antsxnet_cache_directory=antsxnet_cache_directory)
spatial_priors = ants.image_read(spatial_priors_file_name_path)
priors_image_list = ants.ndimage_to_list(spatial_priors)
for i in range(len(priors_image_list)):
priors_image_list[i] = ants.copy_image_info(t1_preprocessed,
priors_image_list[i])
labels_left = labels[1::2]
priors_image_left_list = priors_image_list[1::2]
probability_images_left = list()
foreground_probability_images_left = list()
lower_bound_left = (76, 74, 56)
upper_bound_left = (140, 138, 152)
tmp_cropped = ants.crop_indices(t1_preprocessed, lower_bound_left,
upper_bound_left)
origin_left = tmp_cropped.origin
spacing = tmp_cropped.spacing
direction = tmp_cropped.direction
t1_template_roi_left = ants.crop_indices(t1_template, lower_bound_left,
upper_bound_left)
t1_template_roi_left = (t1_template_roi_left - t1_template_roi_left.min(
)) / (t1_template_roi_left.max() - t1_template_roi_left.min()) * 2.0 - 1.0
t2_template_roi_left = None
if t2_template is not None:
t2_template_roi_left = ants.crop_indices(t2_template, lower_bound_left,
upper_bound_left)
t2_template_roi_left = (t2_template_roi_left -
t2_template_roi_left.min()) / (
t2_template_roi_left.max() -
t2_template_roi_left.min()) * 2.0 - 1.0
labels_right = labels[2::2]
priors_image_right_list = priors_image_list[2::2]
probability_images_right = list()
foreground_probability_images_right = list()
lower_bound_right = (20, 74, 56)
upper_bound_right = (84, 138, 152)
tmp_cropped = ants.crop_indices(t1_preprocessed, lower_bound_right,
upper_bound_right)
origin_right = tmp_cropped.origin
t1_template_roi_right = ants.crop_indices(t1_template, lower_bound_right,
upper_bound_right)
t1_template_roi_right = (
t1_template_roi_right - t1_template_roi_right.min()
) / (t1_template_roi_right.max() - t1_template_roi_right.min()) * 2.0 - 1.0
t2_template_roi_right = None
if t2_template is not None:
t2_template_roi_right = ants.crop_indices(t2_template,
lower_bound_right,
upper_bound_right)
t2_template_roi_right = (t2_template_roi_right -
t2_template_roi_right.min()) / (
t2_template_roi_right.max() -
t2_template_roi_right.min()) * 2.0 - 1.0
################################
#
# Create model
#
################################
channel_size = 1 + len(labels_left)
if t2 is not None:
channel_size += 1
number_of_classification_labels = 1 + len(labels_left)
unet_model = create_unet_model_3d(
(*image_size, channel_size),
number_of_outputs=number_of_classification_labels,
mode="classification",
number_of_filters=(32, 64, 96, 128, 256),
convolution_kernel_size=(3, 3, 3),
deconvolution_kernel_size=(2, 2, 2),
dropout_rate=0.0,
weight_decay=0)
penultimate_layer = unet_model.layers[-2].output
# medial temporal lobe
output1 = Conv3D(
filters=1,
kernel_size=(1, 1, 1),
activation='sigmoid',
kernel_regularizer=regularizers.l2(0.0))(penultimate_layer)
if use_hierarchical_parcellation:
# EC, perirhinal, and parahippo.
output2 = Conv3D(
filters=1,
kernel_size=(1, 1, 1),
activation='sigmoid',
kernel_regularizer=regularizers.l2(0.0))(penultimate_layer)
# Hippocampus
output3 = Conv3D(
filters=1,
kernel_size=(1, 1, 1),
activation='sigmoid',
kernel_regularizer=regularizers.l2(0.0))(penultimate_layer)
unet_model = Model(
inputs=unet_model.input,
outputs=[unet_model.output, output1, output2, output3])
else:
unet_model = Model(inputs=unet_model.input,
outputs=[unet_model.output, output1])
################################
#
# Left: build model and load weights
#
################################
network_name = 'deepFlashLeftT1'
if t2 is not None:
network_name = 'deepFlashLeftBoth'
if use_hierarchical_parcellation:
network_name += "Hierarchical"
if use_rank_intensity:
network_name += "_ri"
if verbose:
print("DeepFlash: retrieving model weights (left).")
weights_file_name = get_pretrained_network(
network_name, antsxnet_cache_directory=antsxnet_cache_directory)
unet_model.load_weights(weights_file_name)
################################
#
# Left: do prediction and normalize to native space
#
################################
if verbose:
print("Prediction (left).")
batchX = None
if use_contralaterality:
batchX = np.zeros((2, *image_size, channel_size))
else:
batchX = np.zeros((1, *image_size, channel_size))
t1_cropped = ants.crop_indices(t1_preprocessed, lower_bound_left,
upper_bound_left)
if use_rank_intensity:
t1_cropped = ants.rank_intensity(t1_cropped)
else:
t1_cropped = ants.histogram_match_image(t1_cropped,
t1_template_roi_left, 255, 64,
False)
batchX[0, :, :, :, 0] = t1_cropped.numpy()
if use_contralaterality:
t1_cropped = ants.crop_indices(t1_preprocessed_flipped,
lower_bound_left, upper_bound_left)
if use_rank_intensity:
t1_cropped = ants.rank_intensity(t1_cropped)
else:
t1_cropped = ants.histogram_match_image(t1_cropped,
t1_template_roi_left, 255,
64, False)
batchX[1, :, :, :, 0] = t1_cropped.numpy()
if t2 is not None:
t2_cropped = ants.crop_indices(t2_preprocessed, lower_bound_left,
upper_bound_left)
if use_rank_intensity:
t2_cropped = ants.rank_intensity(t2_cropped)
else:
t2_cropped = ants.histogram_match_image(t2_cropped,
t2_template_roi_left, 255,
64, False)
batchX[0, :, :, :, 1] = t2_cropped.numpy()
if use_contralaterality:
t2_cropped = ants.crop_indices(t2_preprocessed_flipped,
lower_bound_left, upper_bound_left)
if use_rank_intensity:
t2_cropped = ants.rank_intensity(t2_cropped)
else:
t2_cropped = ants.histogram_match_image(
t2_cropped, t2_template_roi_left, 255, 64, False)
batchX[1, :, :, :, 1] = t2_cropped.numpy()
for i in range(len(priors_image_left_list)):
cropped_prior = ants.crop_indices(priors_image_left_list[i],
lower_bound_left, upper_bound_left)
for j in range(batchX.shape[0]):
batchX[j, :, :, :, i +
(channel_size - len(labels_left))] = cropped_prior.numpy()
predicted_data = unet_model.predict(batchX, verbose=verbose)
for i in range(1 + len(labels_left)):
for j in range(predicted_data[0].shape[0]):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[0][j, :, :, :, i]),
origin=origin_left, spacing=spacing, direction=direction)
if i > 0:
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0)
else:
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0 + 1)
if j == 1: # flipped
probability_array_flipped = np.flip(probability_image.numpy(),
axis=0)
probability_image = ants.from_numpy(
probability_array_flipped,
origin=probability_image.origin,
spacing=probability_image.spacing,
direction=probability_image.direction)
if do_preprocessing:
probability_image = ants.apply_transforms(
fixed=t1,
moving=probability_image,
transformlist=template_transforms['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose)
if j == 0: # not flipped
probability_images_left.append(probability_image)
else: # flipped
probability_images_right.append(probability_image)
################################
#
# Left: do prediction of mtl, hippocampal, and ec regions and normalize to native space
#
################################
for i in range(1, len(predicted_data)):
for j in range(predicted_data[i].shape[0]):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[i][j, :, :, :, 0]),
origin=origin_left, spacing=spacing, direction=direction)
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0)
if j == 1: # flipped
probability_array_flipped = np.flip(probability_image.numpy(),
axis=0)
probability_image = ants.from_numpy(
probability_array_flipped,
origin=probability_image.origin,
spacing=probability_image.spacing,
direction=probability_image.direction)
if do_preprocessing:
probability_image = ants.apply_transforms(
fixed=t1,
moving=probability_image,
transformlist=template_transforms['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose)
if j == 0: # not flipped
foreground_probability_images_left.append(probability_image)
else:
foreground_probability_images_right.append(probability_image)
################################
#
# Right: build model and load weights
#
################################
network_name = 'deepFlashRightT1'
if t2 is not None:
network_name = 'deepFlashRightBoth'
if use_hierarchical_parcellation:
network_name += "Hierarchical"
if use_rank_intensity:
network_name += "_ri"
if verbose:
print("DeepFlash: retrieving model weights (right).")
weights_file_name = get_pretrained_network(
network_name, antsxnet_cache_directory=antsxnet_cache_directory)
unet_model.load_weights(weights_file_name)
################################
#
# Right: do prediction and normalize to native space
#
################################
if verbose:
print("Prediction (right).")
batchX = None
if use_contralaterality:
batchX = np.zeros((2, *image_size, channel_size))
else:
batchX = np.zeros((1, *image_size, channel_size))
t1_cropped = ants.crop_indices(t1_preprocessed, lower_bound_right,
upper_bound_right)
if use_rank_intensity:
t1_cropped = ants.rank_intensity(t1_cropped)
else:
t1_cropped = ants.histogram_match_image(t1_cropped,
t1_template_roi_right, 255, 64,
False)
batchX[0, :, :, :, 0] = t1_cropped.numpy()
if use_contralaterality:
t1_cropped = ants.crop_indices(t1_preprocessed_flipped,
lower_bound_right, upper_bound_right)
if use_rank_intensity:
t1_cropped = ants.rank_intensity(t1_cropped)
else:
t1_cropped = ants.histogram_match_image(t1_cropped,
t1_template_roi_right, 255,
64, False)
batchX[1, :, :, :, 0] = t1_cropped.numpy()
if t2 is not None:
t2_cropped = ants.crop_indices(t2_preprocessed, lower_bound_right,
upper_bound_right)
if use_rank_intensity:
t2_cropped = ants.rank_intensity(t2_cropped)
else:
t2_cropped = ants.histogram_match_image(t2_cropped,
t2_template_roi_right, 255,
64, False)
batchX[0, :, :, :, 1] = t2_cropped.numpy()
if use_contralaterality:
t2_cropped = ants.crop_indices(t2_preprocessed_flipped,
lower_bound_right,
upper_bound_right)
if use_rank_intensity:
t2_cropped = ants.rank_intensity(t2_cropped)
else:
t2_cropped = ants.histogram_match_image(
t2_cropped, t2_template_roi_right, 255, 64, False)
batchX[1, :, :, :, 1] = t2_cropped.numpy()
for i in range(len(priors_image_right_list)):
cropped_prior = ants.crop_indices(priors_image_right_list[i],
lower_bound_right, upper_bound_right)
for j in range(batchX.shape[0]):
batchX[j, :, :, :, i +
(channel_size - len(labels_right))] = cropped_prior.numpy()
predicted_data = unet_model.predict(batchX, verbose=verbose)
for i in range(1 + len(labels_right)):
for j in range(predicted_data[0].shape[0]):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[0][j, :, :, :, i]),
origin=origin_right, spacing=spacing, direction=direction)
if i > 0:
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0)
else:
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0 + 1)
if j == 1: # flipped
probability_array_flipped = np.flip(probability_image.numpy(),
axis=0)
probability_image = ants.from_numpy(
probability_array_flipped,
origin=probability_image.origin,
spacing=probability_image.spacing,
direction=probability_image.direction)
if do_preprocessing:
probability_image = ants.apply_transforms(
fixed=t1,
moving=probability_image,
transformlist=template_transforms['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose)
if j == 0: # not flipped
if use_contralaterality:
probability_images_right[i] = (
probability_images_right[i] + probability_image) / 2
else:
probability_images_right.append(probability_image)
else: # flipped
probability_images_left[i] = (probability_images_left[i] +
probability_image) / 2
################################
#
# Right: do prediction of mtl, hippocampal, and ec regions and normalize to native space
#
################################
for i in range(1, len(predicted_data)):
for j in range(predicted_data[i].shape[0]):
probability_image = \
ants.from_numpy(np.squeeze(predicted_data[i][j, :, :, :, 0]),
origin=origin_right, spacing=spacing, direction=direction)
probability_image = ants.decrop_image(probability_image,
t1_preprocessed * 0)
if j == 1: # flipped
probability_array_flipped = np.flip(probability_image.numpy(),
axis=0)
probability_image = ants.from_numpy(
probability_array_flipped,
origin=probability_image.origin,
spacing=probability_image.spacing,
direction=probability_image.direction)
if do_preprocessing:
probability_image = ants.apply_transforms(
fixed=t1,
moving=probability_image,
transformlist=template_transforms['invtransforms'],
whichtoinvert=[True],
interpolator="linear",
verbose=verbose)
if j == 0: # not flipped
if use_contralaterality:
foreground_probability_images_right[
i - 1] = (foreground_probability_images_right[i - 1] +
probability_image) / 2
else:
foreground_probability_images_right.append(
probability_image)
else:
foreground_probability_images_left[
i - 1] = (foreground_probability_images_left[i - 1] +
probability_image) / 2
################################
#
# Combine priors
#
################################
probability_background_image = ants.image_clone(t1) * 0
for i in range(1, len(probability_images_left)):
probability_background_image += probability_images_left[i]
for i in range(1, len(probability_images_right)):
probability_background_image += probability_images_right[i]
probability_images.append(probability_background_image * -1 + 1)
for i in range(1, len(probability_images_left)):
probability_images.append(probability_images_left[i])
probability_images.append(probability_images_right[i])
################################
#
# Convert probability images to segmentation
#
################################
# image_matrix = ants.image_list_to_matrix(probability_images, t1 * 0 + 1)
# segmentation_matrix = np.argmax(image_matrix, axis=0)
# segmentation_image = ants.matrix_to_images(
# np.expand_dims(segmentation_matrix, axis=0), t1 * 0 + 1)[0]
image_matrix = ants.image_list_to_matrix(
probability_images[1:(len(probability_images))], t1 * 0 + 1)
background_foreground_matrix = np.stack([
ants.image_list_to_matrix([probability_images[0]], t1 * 0 + 1),
np.expand_dims(np.sum(image_matrix, axis=0), axis=0)
])
foreground_matrix = np.argmax(background_foreground_matrix, axis=0)
segmentation_matrix = (np.argmax(image_matrix, axis=0) +
1) * foreground_matrix
segmentation_image = ants.matrix_to_images(
np.expand_dims(segmentation_matrix, axis=0), t1 * 0 + 1)[0]
relabeled_image = ants.image_clone(segmentation_image)
for i in range(len(labels)):
relabeled_image[segmentation_image == i] = labels[i]
foreground_probability_images = list()
for i in range(len(foreground_probability_images_left)):
foreground_probability_images.append(
foreground_probability_images_left[i] +
foreground_probability_images_right[i])
return_dict = None
if use_hierarchical_parcellation:
return_dict = {
'segmentation_image':
relabeled_image,
'probability_images':
probability_images,
'medial_temporal_lobe_probability_image':
foreground_probability_images[0],
'other_region_probability_image':
foreground_probability_images[1],
'hippocampal_probability_image':
foreground_probability_images[2]
}
else:
return_dict = {
'segmentation_image':
relabeled_image,
'probability_images':
probability_images,
'medial_temporal_lobe_probability_image':
foreground_probability_images[0]
}
return (return_dict)
if not os.path.exists(weights_file_name):
weights_file_name = antspynet.get_pretrained_network(
"brainExtraction", weights_file_name)
unet_model.load_weights(weights_file_name)
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
start_time_total = time.time()
print("Reading ", input_file_name)
start_time = time.time()
image = ants.image_read(input_file_name)
mask = ants.image_read(input_mask_file_name)
mask = ants.threshold_image(mask, 0.5, 1.0, 1, 0)
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
print("Normalizing to template")
start_time = time.time()
center_of_mass_template = ants.get_center_of_mass(reorient_template)
center_of_mass_image = ants.get_center_of_mass(image)
translation = np.asarray(center_of_mass_image) - np.asarray(
center_of_mass_template)
xfrm = ants.create_ants_transform(transform_type="Euler3DTransform",
center=np.asarray(center_of_mass_template),
translation=translation)
warped_image = ants.apply_ants_transform_to_image(xfrm,
image,
def sysu_media_wmh_segmentation(flair,
t1=None,
do_preprocessing=True,
use_ensemble=True,
use_axial_slices_only=True,
antsxnet_cache_directory=None,
verbose=False):
"""
Perform WMH segmentation using the winning submission in the MICCAI
2017 challenge by the sysu_media team using FLAIR or T1/FLAIR. The
MICCAI challenge is discussed in
https://pubmed.ncbi.nlm.nih.gov/30908194/
with the sysu_media's team entry is discussed in
https://pubmed.ncbi.nlm.nih.gov/30125711/
with the original implementation available here:
https://github.com/hongweilibran/wmh_ibbmTum
Arguments
---------
flair : ANTsImage
input 3-D FLAIR brain image (not skull-stripped).
t1 : ANTsImage
input 3-D T1 brain image (not skull-stripped).
do_preprocessing : boolean
perform n4 bias correction?
use_ensemble : boolean
check whether to use all 3 sets of weights.
use_axial_slices_only : boolean
If True, use original implementation which was trained on axial slices.
If False, use ANTsXNet variant implementation which applies the slice-by-slice
models to all 3 dimensions and averages the results.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
WMH segmentation probability image
Example
-------
>>> image = ants.image_read("flair.nii.gz")
>>> probability_mask = sysu_media_wmh_segmentation(image)
"""
from ..architectures import create_sysu_media_unet_model_2d
from ..utilities import brain_extraction
from ..utilities import crop_image_center
from ..utilities import get_pretrained_network
from ..utilities import preprocess_brain_image
from ..utilities import pad_or_crop_image_to_size
if flair.dimension != 3:
raise ValueError("Image dimension must be 3.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
################################
#
# Preprocess images
#
################################
flair_preprocessed = flair
if do_preprocessing == True:
flair_preprocessing = preprocess_brain_image(
flair,
truncate_intensity=(0.01, 0.99),
do_brain_extraction=False,
do_bias_correction=True,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
flair_preprocessed = flair_preprocessing["preprocessed_image"]
number_of_channels = 1
if t1 is not None:
t1_preprocessed = t1
if do_preprocessing == True:
t1_preprocessing = preprocess_brain_image(
t1,
truncate_intensity=(0.01, 0.99),
do_brain_extraction=False,
do_bias_correction=True,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
t1_preprocessed = t1_preprocessing["preprocessed_image"]
number_of_channels = 2
################################
#
# Estimate mask
#
################################
brain_mask = None
if verbose == True:
print("Estimating brain mask.")
if t1 is not None:
brain_mask = brain_extraction(t1, modality="t1")
else:
brain_mask = brain_extraction(flair, modality="flair")
reference_image = ants.make_image((200, 200, 200),
voxval=1,
spacing=(1, 1, 1),
origin=(0, 0, 0),
direction=np.identity(3))
center_of_mass_reference = ants.get_center_of_mass(reference_image)
center_of_mass_image = ants.get_center_of_mass(brain_mask)
translation = np.asarray(center_of_mass_image) - np.asarray(
center_of_mass_reference)
xfrm = ants.create_ants_transform(
transform_type="Euler3DTransform",
center=np.asarray(center_of_mass_reference),
translation=translation)
flair_preprocessed_warped = ants.apply_ants_transform_to_image(
xfrm, flair_preprocessed, reference_image)
brain_mask_warped = ants.threshold_image(
ants.apply_ants_transform_to_image(xfrm, brain_mask, reference_image),
0.5, 1.1, 1, 0)
if t1 is not None:
t1_preprocessed_warped = ants.apply_ants_transform_to_image(
xfrm, t1_preprocessed, reference_image)
################################
#
# Gaussian normalize intensity based on brain mask
#
################################
mean_flair = flair_preprocessed_warped[brain_mask_warped > 0].mean()
std_flair = flair_preprocessed_warped[brain_mask_warped > 0].std()
flair_preprocessed_warped = (flair_preprocessed_warped -
mean_flair) / std_flair
if number_of_channels == 2:
mean_t1 = t1_preprocessed_warped[brain_mask_warped > 0].mean()
std_t1 = t1_preprocessed_warped[brain_mask_warped > 0].std()
t1_preprocessed_warped = (t1_preprocessed_warped - mean_t1) / std_t1
################################
#
# Build models and load weights
#
################################
number_of_models = 1
if use_ensemble == True:
number_of_models = 3
unet_models = list()
for i in range(number_of_models):
if number_of_channels == 1:
weights_file_name = get_pretrained_network(
"sysuMediaWmhFlairOnlyModel" + str(i),
antsxnet_cache_directory=antsxnet_cache_directory)
else:
weights_file_name = get_pretrained_network(
"sysuMediaWmhFlairT1Model" + str(i),
antsxnet_cache_directory=antsxnet_cache_directory)
unet_models.append(
create_sysu_media_unet_model_2d((200, 200, number_of_channels)))
unet_models[i].load_weights(weights_file_name)
################################
#
# Extract slices
#
################################
dimensions_to_predict = [2]
if use_axial_slices_only == False:
dimensions_to_predict = list(range(3))
total_number_of_slices = 0
for d in range(len(dimensions_to_predict)):
total_number_of_slices += flair_preprocessed_warped.shape[
dimensions_to_predict[d]]
batchX = np.zeros((total_number_of_slices, 200, 200, number_of_channels))
slice_count = 0
for d in range(len(dimensions_to_predict)):
number_of_slices = flair_preprocessed_warped.shape[
dimensions_to_predict[d]]
if verbose == True:
print("Extracting slices for dimension ", dimensions_to_predict[d],
".")
for i in range(number_of_slices):
flair_slice = pad_or_crop_image_to_size(
ants.slice_image(flair_preprocessed_warped,
dimensions_to_predict[d], i), (200, 200))
batchX[slice_count, :, :, 0] = flair_slice.numpy()
if number_of_channels == 2:
t1_slice = pad_or_crop_image_to_size(
ants.slice_image(t1_preprocessed_warped,
dimensions_to_predict[d], i), (200, 200))
batchX[slice_count, :, :, 1] = t1_slice.numpy()
slice_count += 1
################################
#
# Do prediction and then restack into the image
#
################################
if verbose == True:
print("Prediction.")
prediction = unet_models[0].predict(batchX, verbose=verbose)
if number_of_models > 1:
for i in range(1, number_of_models, 1):
prediction += unet_models[i].predict(batchX, verbose=verbose)
prediction /= number_of_models
permutations = list()
permutations.append((0, 1, 2))
permutations.append((1, 0, 2))
permutations.append((1, 2, 0))
prediction_image_average = ants.image_clone(flair_preprocessed_warped) * 0
current_start_slice = 0
for d in range(len(dimensions_to_predict)):
current_end_slice = current_start_slice + flair_preprocessed_warped.shape[
dimensions_to_predict[d]] - 1
which_batch_slices = range(current_start_slice, current_end_slice)
prediction_per_dimension = prediction[which_batch_slices, :, :, :]
prediction_array = np.transpose(np.squeeze(prediction_per_dimension),
permutations[dimensions_to_predict[d]])
prediction_image = ants.copy_image_info(
flair_preprocessed_warped,
pad_or_crop_image_to_size(ants.from_numpy(prediction_array),
flair_preprocessed_warped.shape))
prediction_image_average = prediction_image_average + (
prediction_image - prediction_image_average) / (d + 1)
current_start_slice = current_end_slice + 1
probability_image = ants.apply_ants_transform_to_image(
ants.invert_ants_transform(xfrm), prediction_image_average, flair)
return (probability_image)
def test_threshold_image_example(self):
image = ants.image_read(ants.get_ants_data('r16'))
timage = ants.threshold_image(image, 0.5, 1e15)
def test_get_centroids_example(self):
image = ants.image_read(ants.get_ants_data("r16"))
image = ants.threshold_image(image, 90, 120)
image = ants.label_clusters(image, 10)
cents = ants.get_centroids(image)
def ew_david(flair,
t1,
do_preprocessing=True,
which_model="sysu",
which_axes=2,
number_of_simulations=0,
sd_affine=0.01,
antsxnet_cache_directory=None,
verbose=False):
"""
Perform White matter hyperintensity probabilistic segmentation
using deep learning
Preprocessing on the training data consisted of:
* n4 bias correction,
* intensity truncation,
* brain extraction, and
* affine registration to MNI.
The input T1 should undergo the same steps. If the input T1 is the raw
T1, these steps can be performed by the internal preprocessing, i.e. set
\code{do_preprocessing = True}
Arguments
---------
flair : ANTsImage
input 3-D FLAIR brain image (not skull-stripped).
t1 : ANTsImage
input 3-D T1 brain image (not skull-stripped).
do_preprocessing : boolean
perform n4 bias correction, intensity truncation, brain extraction.
which_model : string
one of:
* "sysu" -- same as the original sysu network (without site specific preprocessing),
* "sysu-ri" -- same as "sysu" but using ranked intensity scaling for input images,
* "sysuWithAttention" -- "sysu" with attention gating,
* "sysuWithAttentionAndSite" -- "sysu" with attention gating with site branch (see "sysuWithSite"),
* "sysuPlus" -- "sysu" with attention gating and nn-Unet activation,
* "sysuPlusSeg" -- "sysuPlus" with deep_atropos segmentation in an additional channel, and
* "sysuWithSite" -- "sysu" with global pooling on encoding channels to predict "site".
* "sysuPlusSegWithSite" -- "sysuPlusSeg" combined with "sysuWithSite"
In addition to both modalities, all models have T1-only and flair-only variants except
for "sysuPlusSeg" (which only has a T1-only variant) or "sysu-ri" (which has neither single
modality variant).
which_axes : string or scalar or tuple/vector
apply 2-D model to 1 or more axes. In addition to a scalar
or vector, e.g., which_axes = (0, 2), one can use "max" for the
axis with maximum anisotropy (default) or "all" for all axes.
number_of_simulations : integer
Number of random affine perturbations to transform the input.
sd_affine : float
Define the standard deviation of the affine transformation parameter.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
WMH segmentation probability image
Example
-------
>>> image = ants.image_read("flair.nii.gz")
>>> probability_mask = sysu_media_wmh_segmentation(image)
"""
from ..architectures import create_unet_model_2d
from ..utilities import deep_atropos
from ..utilities import get_pretrained_network
from ..utilities import preprocess_brain_image
from ..utilities import randomly_transform_image_data
from ..utilities import pad_or_crop_image_to_size
do_t1_only = False
do_flair_only = False
if flair is None and t1 is not None:
do_t1_only = True
elif flair is not None and t1 is None:
do_flair_only = True
use_t1_segmentation = False
if "Seg" in which_model:
if do_flair_only:
raise ValueError("Segmentation requires T1.")
else:
use_t1_segmentation = True
if use_t1_segmentation and do_preprocessing == False:
raise ValueError(
"Using the t1 segmentation requires do_preprocessing=True.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
do_slicewise = True
if do_slicewise == False:
raise ValueError("Not available.")
# ################################
# #
# # Preprocess images
# #
# ################################
# t1_preprocessed = t1
# t1_preprocessing = None
# if do_preprocessing == True:
# t1_preprocessing = preprocess_brain_image(t1,
# truncate_intensity=(0.01, 0.99),
# brain_extraction_modality="t1",
# template="croppedMni152",
# template_transform_type="antsRegistrationSyNQuickRepro[a]",
# do_bias_correction=True,
# do_denoising=False,
# antsxnet_cache_directory=antsxnet_cache_directory,
# verbose=verbose)
# t1_preprocessed = t1_preprocessing["preprocessed_image"] * t1_preprocessing['brain_mask']
# flair_preprocessed = flair
# if do_preprocessing == True:
# flair_preprocessing = preprocess_brain_image(flair,
# truncate_intensity=(0.01, 0.99),
# brain_extraction_modality="t1",
# do_bias_correction=True,
# do_denoising=False,
# antsxnet_cache_directory=antsxnet_cache_directory,
# verbose=verbose)
# flair_preprocessed = ants.apply_transforms(fixed=t1_preprocessed,
# moving=flair_preprocessing["preprocessed_image"],
# transformlist=t1_preprocessing['template_transforms']['fwdtransforms'])
# flair_preprocessed = flair_preprocessed * t1_preprocessing['brain_mask']
# ################################
# #
# # Build model and load weights
# #
# ################################
# patch_size = (112, 112, 112)
# stride_length = (t1_preprocessed.shape[0] - patch_size[0],
# t1_preprocessed.shape[1] - patch_size[1],
# t1_preprocessed.shape[2] - patch_size[2])
# classes = ("background", "wmh" )
# number_of_classification_labels = len(classes)
# labels = (0, 1)
# image_modalities = ("T1", "FLAIR")
# channel_size = len(image_modalities)
# unet_model = create_unet_model_3d((*patch_size, channel_size),
# number_of_outputs = number_of_classification_labels,
# number_of_layers = 4, number_of_filters_at_base_layer = 16, dropout_rate = 0.0,
# convolution_kernel_size = (3, 3, 3), deconvolution_kernel_size = (2, 2, 2),
# weight_decay = 1e-5, additional_options=("attentionGating"))
# weights_file_name = get_pretrained_network("ewDavidWmhSegmentationWeights",
# antsxnet_cache_directory=antsxnet_cache_directory)
# unet_model.load_weights(weights_file_name)
# ################################
# #
# # Do prediction and normalize to native space
# #
# ################################
# if verbose == True:
# print("ew_david: prediction.")
# batchX = np.zeros((8, *patch_size, channel_size))
# t1_preprocessed = (t1_preprocessed - t1_preprocessed.mean()) / t1_preprocessed.std()
# t1_patches = extract_image_patches(t1_preprocessed, patch_size=patch_size,
# max_number_of_patches="all", stride_length=stride_length,
# return_as_array=True)
# batchX[:,:,:,:,0] = t1_patches
# flair_preprocessed = (flair_preprocessed - flair_preprocessed.mean()) / flair_preprocessed.std()
# flair_patches = extract_image_patches(flair_preprocessed, patch_size=patch_size,
# max_number_of_patches="all", stride_length=stride_length,
# return_as_array=True)
# batchX[:,:,:,:,1] = flair_patches
# predicted_data = unet_model.predict(batchX, verbose=verbose)
# probability_images = list()
# for i in range(len(labels)):
# print("Reconstructing image", classes[i])
# reconstructed_image = reconstruct_image_from_patches(predicted_data[:,:,:,:,i],
# domain_image=t1_preprocessed, stride_length=stride_length)
# if do_preprocessing == True:
# probability_images.append(ants.apply_transforms(fixed=t1,
# moving=reconstructed_image,
# transformlist=t1_preprocessing['template_transforms']['invtransforms'],
# whichtoinvert=[True], interpolator="linear", verbose=verbose))
# else:
# probability_images.append(reconstructed_image)
# return(probability_images[1])
else: # do_slicewise
################################
#
# Preprocess images
#
################################
use_rank_intensity_scaling = False
if "-ri" in which_model:
use_rank_intensity_scaling = True
t1_preprocessed = None
t1_preprocessing = None
brain_mask = None
if t1 is not None:
if do_preprocessing == True:
t1_preprocessing = preprocess_brain_image(
t1,
truncate_intensity=(0.01, 0.995),
brain_extraction_modality="t1",
do_bias_correction=False,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
brain_mask = ants.threshold_image(
t1_preprocessing["brain_mask"], 0.5, 1, 1, 0)
t1_preprocessed = t1_preprocessing["preprocessed_image"]
t1_segmentation = None
if use_t1_segmentation:
atropos_seg = deep_atropos(t1,
do_preprocessing=True,
verbose=verbose)
t1_segmentation = atropos_seg['segmentation_image']
flair_preprocessed = None
if flair is not None:
flair_preprocessed = flair
if do_preprocessing == True:
if brain_mask is None:
flair_preprocessing = preprocess_brain_image(
flair,
truncate_intensity=(0.01, 0.995),
brain_extraction_modality="flair",
do_bias_correction=False,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
brain_mask = ants.threshold_image(
flair_preprocessing["brain_mask"], 0.5, 1, 1, 0)
else:
flair_preprocessing = preprocess_brain_image(
flair,
truncate_intensity=None,
brain_extraction_modality=None,
do_bias_correction=False,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
flair_preprocessed = flair_preprocessing["preprocessed_image"]
if t1_preprocessed is not None:
t1_preprocessed = t1_preprocessed * brain_mask
if flair_preprocessed is not None:
flair_preprocessed = flair_preprocessed * brain_mask
if t1_preprocessed is not None:
resampling_params = list(ants.get_spacing(t1_preprocessed))
else:
resampling_params = list(ants.get_spacing(flair_preprocessed))
do_resampling = False
for d in range(len(resampling_params)):
if resampling_params[d] < 0.8:
resampling_params[d] = 1.0
do_resampling = True
resampling_params = tuple(resampling_params)
if do_resampling:
if flair_preprocessed is not None:
flair_preprocessed = ants.resample_image(flair_preprocessed,
resampling_params,
use_voxels=False,
interp_type=0)
if t1_preprocessed is not None:
t1_preprocessed = ants.resample_image(t1_preprocessed,
resampling_params,
use_voxels=False,
interp_type=0)
if t1_segmentation is not None:
t1_segmentation = ants.resample_image(t1_segmentation,
resampling_params,
use_voxels=False,
interp_type=1)
if brain_mask is not None:
brain_mask = ants.resample_image(brain_mask,
resampling_params,
use_voxels=False,
interp_type=1)
################################
#
# Build model and load weights
#
################################
template_size = (208, 208)
image_modalities = ("T1", "FLAIR")
if do_flair_only:
image_modalities = ("FLAIR", )
elif do_t1_only:
image_modalities = ("T1", )
if use_t1_segmentation:
image_modalities = (*image_modalities, "T1Seg")
channel_size = len(image_modalities)
unet_model = None
if which_model == "sysu" or which_model == "sysu-ri":
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("initialConvolutionKernelSize[5]", ))
elif which_model == "sysuWithAttention":
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("attentionGating",
"initialConvolutionKernelSize[5]"))
elif which_model == "sysuWithAttentionAndSite":
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
scalar_output_size=3,
scalar_output_activation="softmax",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("attentionGating",
"initialConvolutionKernelSize[5]"))
elif which_model == "sysuWithSite":
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
scalar_output_size=3,
scalar_output_activation="softmax",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("initialConvolutionKernelSize[5]", ))
elif which_model == "sysuPlusSegWithSite":
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
scalar_output_size=3,
scalar_output_activation="softmax",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("nnUnetActivationStyle", "attentionGating",
"initialConvolutionKernelSize[5]"))
else:
unet_model = create_unet_model_2d(
(*template_size, channel_size),
number_of_outputs=1,
mode="sigmoid",
number_of_filters=(64, 96, 128, 256, 512),
dropout_rate=0.0,
convolution_kernel_size=(3, 3),
deconvolution_kernel_size=(2, 2),
weight_decay=0,
additional_options=("nnUnetActivationStyle", "attentionGating",
"initialConvolutionKernelSize[5]"))
if verbose == True:
print("ewDavid: retrieving model weights.")
weights_file_name = None
if which_model == "sysu" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysu",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysu-ri" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuRankedIntensity",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysu" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysu" and flair is not None and t1 is None:
weights_file_name = get_pretrained_network(
"ewDavidSysuFlairOnly",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttention" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttention",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttention" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttentionT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttention" and flair is not None and t1 is None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttentionFlairOnly",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttentionAndSite" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttentionAndSite",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttentionAndSite" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttentionAndSiteT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithAttentionAndSite" and flair is not None and t1 is None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithAttentionAndSiteFlairOnly",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlus" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlus",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlus" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlus" and flair is not None and t1 is None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusFlairOnly",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlusSeg" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusSeg",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlusSeg" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusSegT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlusSegWithSite" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusSegWithSite",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuPlusSegWithSite" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuPlusSegWithSiteT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithSite" and flair is not None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithSite",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithSite" and flair is None and t1 is not None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithSiteT1Only",
antsxnet_cache_directory=antsxnet_cache_directory)
elif which_model == "sysuWithSite" and flair is not None and t1 is None:
weights_file_name = get_pretrained_network(
"ewDavidSysuWithSiteFlairOnly",
antsxnet_cache_directory=antsxnet_cache_directory)
else:
raise ValueError(
"Incorrect model specification or image combination.")
unet_model.load_weights(weights_file_name)
################################
#
# Data augmentation and extract slices
#
################################
wmh_probability_image = None
if t1 is not None:
wmh_probability_image = ants.image_clone(t1_preprocessed) * 0
else:
wmh_probability_image = ants.image_clone(flair_preprocessed) * 0
wmh_site = np.array([0, 0, 0])
data_augmentation = None
if number_of_simulations > 0:
if do_flair_only:
data_augmentation = randomly_transform_image_data(
reference_image=flair_preprocessed,
input_image_list=[[flair_preprocessed]],
number_of_simulations=number_of_simulations,
transform_type='affine',
sd_affine=sd_affine,
input_image_interpolator='linear')
elif do_t1_only:
if use_t1_segmentation:
data_augmentation = randomly_transform_image_data(
reference_image=t1_preprocessed,
input_image_list=[[t1_preprocessed]],
segmentation_image_list=[t1_segmentation],
number_of_simulations=number_of_simulations,
transform_type='affine',
sd_affine=sd_affine,
input_image_interpolator='linear',
segmentation_image_interpolator='nearestNeighbor')
else:
data_augmentation = randomly_transform_image_data(
reference_image=t1_preprocessed,
input_image_list=[[t1_preprocessed]],
number_of_simulations=number_of_simulations,
transform_type='affine',
sd_affine=sd_affine,
input_image_interpolator='linear')
else:
if use_t1_segmentation:
data_augmentation = randomly_transform_image_data(
reference_image=t1_preprocessed,
input_image_list=[[
flair_preprocessed, t1_preprocessed
]],
segmentation_image_list=[t1_segmentation],
number_of_simulations=number_of_simulations,
transform_type='affine',
sd_affine=sd_affine,
input_image_interpolator='linear',
segmentation_image_interpolator='nearestNeighbor')
else:
data_augmentation = randomly_transform_image_data(
reference_image=t1_preprocessed,
input_image_list=[[
flair_preprocessed, t1_preprocessed
]],
number_of_simulations=number_of_simulations,
transform_type='affine',
sd_affine=sd_affine,
input_image_interpolator='linear')
dimensions_to_predict = list((0, ))
if which_axes == "max":
spacing = ants.get_spacing(wmh_probability_image)
dimensions_to_predict = (spacing.index(max(spacing)), )
elif which_axes == "all":
dimensions_to_predict = list(range(3))
else:
if isinstance(which_axes, int):
dimensions_to_predict = list((which_axes, ))
else:
dimensions_to_predict = list(which_axes)
total_number_of_slices = 0
for d in range(len(dimensions_to_predict)):
total_number_of_slices += wmh_probability_image.shape[
dimensions_to_predict[d]]
batchX = np.zeros(
(total_number_of_slices, *template_size, channel_size))
for n in range(number_of_simulations + 1):
batch_flair = flair_preprocessed
batch_t1 = t1_preprocessed
batch_t1_segmentation = t1_segmentation
batch_brain_mask = brain_mask
if n > 0:
if do_flair_only:
batch_flair = data_augmentation['simulated_images'][n -
1][0]
batch_brain_mask = ants.apply_ants_transform_to_image(
data_augmentation['simulated_transforms'][n - 1],
brain_mask,
flair_preprocessed,
interpolation="nearestneighbor")
elif do_t1_only:
batch_t1 = data_augmentation['simulated_images'][n - 1][0]
batch_brain_mask = ants.apply_ants_transform_to_image(
data_augmentation['simulated_transforms'][n - 1],
brain_mask,
t1_preprocessed,
interpolation="nearestneighbor")
else:
batch_flair = data_augmentation['simulated_images'][n -
1][0]
batch_t1 = data_augmentation['simulated_images'][n - 1][1]
batch_brain_mask = ants.apply_ants_transform_to_image(
data_augmentation['simulated_transforms'][n - 1],
brain_mask,
flair_preprocessed,
interpolation="nearestneighbor")
if use_t1_segmentation:
batch_t1_segmentation = data_augmentation[
'simulated_segmentation_images'][n - 1]
if use_rank_intensity_scaling:
if batch_t1 is not None:
batch_t1 = ants.rank_intensity(batch_t1,
batch_brain_mask) - 0.5
if batch_flair is not None:
batch_flair = ants.rank_intensity(flair_preprocessed,
batch_brain_mask) - 0.5
else:
if batch_t1 is not None:
batch_t1 = (batch_t1 -
batch_t1[batch_brain_mask == 1].mean()
) / batch_t1[batch_brain_mask == 1].std()
if batch_flair is not None:
batch_flair = (
batch_flair -
batch_flair[batch_brain_mask == 1].mean()
) / batch_flair[batch_brain_mask == 1].std()
slice_count = 0
for d in range(len(dimensions_to_predict)):
number_of_slices = None
if batch_t1 is not None:
number_of_slices = batch_t1.shape[dimensions_to_predict[d]]
else:
number_of_slices = batch_flair.shape[
dimensions_to_predict[d]]
if verbose == True:
print("Extracting slices for dimension ",
dimensions_to_predict[d])
for i in range(number_of_slices):
brain_mask_slice = pad_or_crop_image_to_size(
ants.slice_image(batch_brain_mask,
dimensions_to_predict[d], i),
template_size)
channel_count = 0
if batch_flair is not None:
flair_slice = pad_or_crop_image_to_size(
ants.slice_image(batch_flair,
dimensions_to_predict[d], i),
template_size)
flair_slice[brain_mask_slice == 0] = 0
batchX[slice_count, :, :,
channel_count] = flair_slice.numpy()
channel_count += 1
if batch_t1 is not None:
t1_slice = pad_or_crop_image_to_size(
ants.slice_image(batch_t1,
dimensions_to_predict[d], i),
template_size)
t1_slice[brain_mask_slice == 0] = 0
batchX[slice_count, :, :,
channel_count] = t1_slice.numpy()
channel_count += 1
if t1_segmentation is not None:
t1_segmentation_slice = pad_or_crop_image_to_size(
ants.slice_image(batch_t1_segmentation,
dimensions_to_predict[d], i),
template_size)
t1_segmentation_slice[brain_mask_slice == 0] = 0
batchX[slice_count, :, :,
channel_count] = t1_segmentation_slice.numpy(
) / 6 - 0.5
slice_count += 1
################################
#
# Do prediction and then restack into the image
#
################################
if verbose == True:
if n == 0:
print("Prediction")
else:
print("Prediction (simulation " + str(n) + ")")
prediction = unet_model.predict(batchX, verbose=verbose)
permutations = list()
permutations.append((0, 1, 2))
permutations.append((1, 0, 2))
permutations.append((1, 2, 0))
prediction_image_average = ants.image_clone(
wmh_probability_image) * 0
current_start_slice = 0
for d in range(len(dimensions_to_predict)):
current_end_slice = current_start_slice + wmh_probability_image.shape[
dimensions_to_predict[d]]
which_batch_slices = range(current_start_slice,
current_end_slice)
if isinstance(prediction, list):
prediction_per_dimension = prediction[0][
which_batch_slices, :, :, 0]
else:
prediction_per_dimension = prediction[
which_batch_slices, :, :, 0]
prediction_array = np.transpose(
np.squeeze(prediction_per_dimension),
permutations[dimensions_to_predict[d]])
prediction_image = ants.copy_image_info(
wmh_probability_image,
pad_or_crop_image_to_size(
ants.from_numpy(prediction_array),
wmh_probability_image.shape))
prediction_image_average = prediction_image_average + (
prediction_image - prediction_image_average) / (d + 1)
current_start_slice = current_end_slice
wmh_probability_image = wmh_probability_image + (
prediction_image_average - wmh_probability_image) / (n + 1)
if isinstance(prediction, list):
wmh_site = wmh_site + (np.mean(prediction[1], axis=0) -
wmh_site) / (n + 1)
if do_resampling:
if t1 is not None:
wmh_probability_image = ants.resample_image_to_target(
wmh_probability_image, t1)
if flair is not None:
wmh_probability_image = ants.resample_image_to_target(
wmh_probability_image, flair)
if isinstance(prediction, list):
return ([wmh_probability_image, wmh_site])
else:
return (wmh_probability_image)
def hippmapp3r_segmentation(t1,
do_preprocessing=True,
antsxnet_cache_directory=None,
verbose=False):
"""
Perform HippMapp3r (hippocampal) segmentation described in
https://www.ncbi.nlm.nih.gov/pubmed/31609046
with models and architecture ported from
https://github.com/mgoubran/HippMapp3r
Additional documentation and attribution resources found at
https://hippmapp3r.readthedocs.io/en/latest/
Preprocessing consists of:
* n4 bias correction and
* brain extraction
The input T1 should undergo the same steps. If the input T1 is the raw
T1, these steps can be performed by the internal preprocessing, i.e. set
do_preprocessing = True
Arguments
---------
t1 : ANTsImage
input image
do_preprocessing : boolean
See description above.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
ANTs labeled hippocampal image.
Example
-------
>>> mask = hippmapp3r_segmentation(t1)
"""
from ..architectures import create_hippmapp3r_unet_model_3d
from ..utilities import preprocess_brain_image
from ..utilities import get_pretrained_network
from ..utilities import get_antsxnet_data
if t1.dimension != 3:
raise ValueError("Image dimension must be 3.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
if verbose == True:
print("************* Preprocessing ***************")
print("")
t1_preprocessed = t1
if do_preprocessing == True:
t1_preprocessing = preprocess_brain_image(
t1,
truncate_intensity=None,
brain_extraction_modality="t1",
template=None,
do_bias_correction=True,
do_denoising=False,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
t1_preprocessed = t1_preprocessing[
"preprocessed_image"] * t1_preprocessing['brain_mask']
if verbose == True:
print("************* Initial stage segmentation ***************")
print("")
# Normalize to mprage_hippmapp3r space
if verbose == True:
print(" HippMapp3r: template normalization.")
template_file_name_path = get_antsxnet_data(
"mprage_hippmapp3r", antsxnet_cache_directory=antsxnet_cache_directory)
template_image = ants.image_read(template_file_name_path)
registration = ants.registration(
fixed=template_image,
moving=t1_preprocessed,
type_of_transform="antsRegistrationSyNQuickRepro[t]",
verbose=verbose)
image = registration['warpedmovout']
transforms = dict(fwdtransforms=registration['fwdtransforms'],
invtransforms=registration['invtransforms'])
# Threshold at 10th percentile of non-zero voxels in "robust range (fslmaths)"
if verbose == True:
print(" HippMapp3r: threshold.")
image_array = image.numpy()
image_robust_range = np.quantile(image_array[np.where(image_array != 0)],
(0.02, 0.98))
threshold_value = 0.10 * (image_robust_range[1] -
image_robust_range[0]) + image_robust_range[0]
thresholded_mask = ants.threshold_image(image, -10000, threshold_value, 0,
1)
thresholded_image = image * thresholded_mask
# Standardize image
if verbose == True:
print(" HippMapp3r: standardize.")
mean_image = np.mean(thresholded_image[thresholded_mask == 1])
sd_image = np.std(thresholded_image[thresholded_mask == 1])
image_normalized = (image - mean_image) / sd_image
image_normalized = image_normalized * thresholded_mask
# Trim and resample image
if verbose == True:
print(" HippMapp3r: trim and resample to (160, 160, 128).")
image_cropped = ants.crop_image(image_normalized, thresholded_mask, 1)
shape_initial_stage = (160, 160, 128)
image_resampled = ants.resample_image(image_cropped,
shape_initial_stage,
use_voxels=True,
interp_type=1)
if verbose == True:
print(" HippMapp3r: generate first network and download weights.")
model_initial_stage = create_hippmapp3r_unet_model_3d(
(*shape_initial_stage, 1), do_first_network=True)
initial_stage_weights_file_name = get_pretrained_network(
"hippMapp3rInitial", antsxnet_cache_directory=antsxnet_cache_directory)
model_initial_stage.load_weights(initial_stage_weights_file_name)
if verbose == True:
print(" HippMapp3r: prediction.")
data_initial_stage = np.expand_dims(image_resampled.numpy(), axis=0)
data_initial_stage = np.expand_dims(data_initial_stage, axis=-1)
mask_array = model_initial_stage.predict(data_initial_stage,
verbose=verbose)
mask_image_resampled = ants.copy_image_info(
image_resampled, ants.from_numpy(np.squeeze(mask_array)))
mask_image = ants.resample_image(mask_image_resampled,
image.shape,
use_voxels=True,
interp_type=0)
mask_image[mask_image >= 0.5] = 1
mask_image[mask_image < 0.5] = 0
#########################################
#
# Perform refined (stage 2) segmentation
#
if verbose == True:
print("")
print("")
print("************* Refine stage segmentation ***************")
print("")
mask_array = np.squeeze(mask_array)
centroid_indices = np.where(mask_array == 1)
centroid = np.zeros((3, ))
centroid[0] = centroid_indices[0].mean()
centroid[1] = centroid_indices[1].mean()
centroid[2] = centroid_indices[2].mean()
shape_refine_stage = (112, 112, 64)
lower = (np.floor(centroid - 0.5 * np.array(shape_refine_stage)) -
1).astype(int)
upper = (lower + np.array(shape_refine_stage)).astype(int)
image_trimmed = ants.crop_indices(image_resampled, lower.astype(int),
upper.astype(int))
if verbose == True:
print(" HippMapp3r: generate second network and download weights.")
model_refine_stage = create_hippmapp3r_unet_model_3d(
(*shape_refine_stage, 1), do_first_network=False)
refine_stage_weights_file_name = get_pretrained_network(
"hippMapp3rRefine", antsxnet_cache_directory=antsxnet_cache_directory)
model_refine_stage.load_weights(refine_stage_weights_file_name)
data_refine_stage = np.expand_dims(image_trimmed.numpy(), axis=0)
data_refine_stage = np.expand_dims(data_refine_stage, axis=-1)
if verbose == True:
print(" HippMapp3r: Monte Carlo iterations (SpatialDropout).")
number_of_mci_iterations = 30
prediction_refine_stage = np.zeros(shape_refine_stage)
for i in range(number_of_mci_iterations):
tf.random.set_seed(i)
if verbose == True:
print(" Monte Carlo iteration", i + 1, "out of",
number_of_mci_iterations)
prediction_refine_stage = \
(np.squeeze(model_refine_stage.predict(data_refine_stage, verbose=verbose)) + \
i * prediction_refine_stage ) / (i + 1)
prediction_refine_stage_array = np.zeros(image_resampled.shape)
prediction_refine_stage_array[lower[0]:upper[0], lower[1]:upper[1],
lower[2]:upper[2]] = prediction_refine_stage
probability_mask_refine_stage_resampled = ants.copy_image_info(
image_resampled, ants.from_numpy(prediction_refine_stage_array))
segmentation_image_resampled = ants.label_clusters(ants.threshold_image(
probability_mask_refine_stage_resampled, 0.0, 0.5, 0, 1),
min_cluster_size=10)
segmentation_image_resampled[segmentation_image_resampled > 2] = 0
geom = ants.label_geometry_measures(segmentation_image_resampled)
if len(geom['VolumeInMillimeters']) < 2:
raise ValueError("Error: left and right hippocampus not found.")
if geom['Centroid_x'][0] < geom['Centroid_x'][1]:
segmentation_image_resampled[segmentation_image_resampled == 1] = 3
segmentation_image_resampled[segmentation_image_resampled == 2] = 1
segmentation_image_resampled[segmentation_image_resampled == 3] = 2
segmentation_image = ants.apply_transforms(
fixed=t1,
moving=segmentation_image_resampled,
transformlist=transforms['invtransforms'],
whichtoinvert=[True],
interpolator="genericLabel",
verbose=verbose)
return (segmentation_image)
"brainSegmentationPatchBased", weights_file_name)
unet_model.load_weights(weights_file_name)
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
# Process input
start_time_total = time.time()
print("Reading ", input_file_name)
start_time = time.time()
image = ants.image_read(input_file_name)
mask = ants.image_read(input_mask_file_name)
mask = ants.threshold_image(mask, 0.4999, 1.0001, 1, 0)
image = image * mask
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
print("Extracting patches based on mask.")
start_time = time.time()
image_patches = antspynet.extract_image_patches(image,
stride_length=stride_length,
patch_size=patch_size,
max_number_of_patches="all",
mask_image=mask,
return_as_array=True)
image_patches = (image_patches - image_patches.min()) / (image_patches.max() -
def neural_style_transfer(content_image,
style_images,
initial_combination_image=None,
number_of_iterations=10,
learning_rate=1.0,
total_variation_weight=8.5e-5,
content_weight=0.025,
style_image_weights=1.0,
content_layer_names=['block5_conv2'],
style_layer_names="all",
content_mask=None,
style_masks=None,
use_shifted_activations=True,
use_chained_inference=True,
verbose=False,
output_prefix=None):
"""
The popular neural style transfer described here:
https://arxiv.org/abs/1508.06576 and https://arxiv.org/abs/1605.04603
and taken from François Chollet's implementation
https://keras.io/examples/generative/neural_style_transfer/
and titu1994's modifications:
https://github.com/titu1994/Neural-Style-Transfer
in order to possibly modify and experiment with medical images.
Arguments
---------
content_image : ANTsImage (1 or 3-component)
Content (or base) image.
style_images : ANTsImage or list of ANTsImages
Style (or reference) image.
initial_combination_image : ANTsImage (1 or 3-component)
Starting point for the optimization. Allows one to start from the
output from a previous run. Otherwise, start from the content image.
Note that the original paper starts with a noise image.
number_of_iterations : integer
Number of gradient steps taken during optimization.
learning_rate : float
Parameter for Adam optimization.
total_variation_weight : float
A penalty on the regularization term to keep the features
of the output image locally coherent.
content_weight : float
Weight of the content layers in the optimization function.
style_image_weights : float or list of floats
Weights of the style term in the optimization function for each
style image. Can either specify a single scalar to be used for
all the images or one for each image. The
style term computes the sum of the L2 norm between the Gram
matrices of the different layers (using ImageNet-trained VGG)
of the style and content images.
content_layer_names : list of strings
Names of VGG layers from which to compute the content loss.
style_layer_names : list of strings
Names of VGG layers from which to compute the style loss. If "all",
the layers used are ['block1_conv1', 'block1_conv2', 'block2_conv1',
'block2_conv2', 'block3_conv1', 'block3_conv2', 'block3_conv3',
'block3_conv4', 'block4_conv1', 'block4_conv2', 'block4_conv3',
'block4_conv4', 'block5_conv1', 'block5_conv2', 'block5_conv3',
'block5_conv4']. This is a proposed improvement from
https://arxiv.org/abs/1605.04603. In the original implementation, the
layers used are: ['block1_conv1', 'block2_conv1', 'block3_conv1',
'block4_conv1', 'block5_conv1'].
content_mask : ANTsImage
Specify the region for content consideration.
style_masks : ANTsImage or list of ANTsImages
Specify the region for style consideration.
use_shifted_activations : boolean
Use shifted activations in calculating the Gram matrix (improvement
mentioned in https://arxiv.org/abs/1605.04603).
use_chained_inference : boolean
Another proposed improvement from https://arxiv.org/abs/1605.04603.
verbose : boolean
Print progress to the screen.
output_prefix : string
If specified, outputs a png image to disk at each iteration.
Returns
-------
ANTs 3-component image.
Example
-------
>>> image = neural_style_transfer(content_image, style_image)
"""
def preprocess_ants_image(image, do_scale_and_center=True):
array = None
if image.components == 1:
array = image.numpy()
array = np.expand_dims(array, 2)
array = np.repeat(array, 3, 2)
elif image.components == 3:
vector_image = image
image_channels = ants.split_channels(vector_image)
array = np.concatenate([
np.expand_dims(image_channels[0].numpy(), axis=2),
np.expand_dims(image_channels[1].numpy(), axis=2),
np.expand_dims(image_channels[2].numpy(), axis=2)
],
axis=2)
else:
raise ValueError("Unexpected number of components.")
if do_scale_and_center == True:
for i in range(3):
array[:, :, i] = (array[:, :, i] - array[:, :, i].min()) / (
array[:, :, i].max() - array[:, :, i].min())
array *= 255.0
# RGB -> BGR
array = array[:, :, ::-1]
array[:, :, 0] -= 103.939
array[:, :, 1] -= 116.779
array[:, :, 2] -= 123.68
array = np.expand_dims(array, 0)
return (array)
def postprocess_array(array, reference_image):
array = np.squeeze(array)
array[:, :, 0] += 103.939
array[:, :, 1] += 116.779
array[:, :, 2] += 123.68
# BGR -> RGB
array = array[:, :, ::-1]
array = np.clip(array, 0, 255)
image = ants.from_numpy(array,
origin=reference_image.origin,
spacing=reference_image.spacing,
direction=reference_image.direction,
has_components=True)
return (image)
def gram_matrix(x, shifted_activations=False):
F = K.batch_flatten(K.permute_dimensions(x, (2, 0, 1)))
if shifted_activations:
F = F - 1
gram = K.dot(F, K.transpose(F))
return (gram)
def process_mask(mask, shape):
mask_processed = (tf.image.resize(
mask,
size=[shape[0], shape[1]],
method=tf.image.ResizeMethod.NEAREST_NEIGHBOR)).numpy()
mask_processed_tensor = np.empty(shape)
for i in range(shape[2]):
mask_processed_tensor[:, :, i] = mask_processed[:, :, 0]
return (mask_processed_tensor)
def style_loss(style_features,
combination_features,
image_shape,
style_mask=None,
content_mask=None):
if content_mask is not None:
mask_tensor = K.variable(
process_mask(content_mask, combination_features.shape))
combination_features = combination_features * K.stop_gradient(
mask_tensor)
del mask_tensor
if style_mask is not None:
mask_tensor = K.variable(
process_mask(style_mask, style_features.shape))
style_features = style_features * K.stop_gradient(mask_tensor)
if content_mask is not None:
combination_features = combination_features * K.stop_gradient(
mask_tensor)
del mask_tensor
style_gram = gram_matrix(style_features, use_shifted_activations)
content_gram = gram_matrix(combination_features,
use_shifted_activations)
size = image_shape[0] * image_shape[1]
number_of_channels = 3
loss = tf.reduce_sum(
tf.square(style_gram - content_gram)) / (4.0 *
(number_of_channels**2) *
(size**2))
return (loss)
def content_loss(content_features, combination_features):
loss = tf.reduce_sum(tf.square(content_features -
combination_features))
return (loss)
def total_variation_loss(x):
shape = x.shape
a = tf.square(x[:, :(shape[1] - 1), :(shape[2] - 1), :] -
x[:, 1:, :(shape[2] - 1), :])
b = tf.square(x[:, :(shape[1] - 1), :(shape[2] - 1), :] -
x[:, :(shape[1] - 1), 1:, :])
loss = tf.reduce_sum(tf.pow(a + b, 1.25))
return (loss)
def compute_total_loss(content_array,
style_array_list,
combination_tensor,
feature_model,
content_layer_names,
style_layer_names,
image_shape,
content_mask_tensor=None,
style_mask_tensor_list=None):
number_of_style_images = len(style_array_list)
input_arrays = list()
input_arrays.append(content_array)
for i in range(number_of_style_images):
input_arrays.append(style_array_list[i])
input_arrays.append(combination_tensor)
input_tensor = tf.concat(input_arrays, axis=0)
features = feature_model(input_tensor)
total_loss = tf.zeros(shape=())
# content loss
for i in range(len(content_layer_names)):
layer_features = features[content_layer_names[i]]
content_features = layer_features[0, :, :, :]
combination_features = layer_features[2, :, :, :]
total_loss = total_loss + (
content_loss(content_features, combination_features) *
content_weight / len(content_layer_names))
# style loss
if use_chained_inference:
for i in range(len(style_layer_names) - 1):
layer_features = features[style_layer_names[i]]
style_features = layer_features[1:(number_of_style_images +
1), :, :, :]
combination_features = layer_features[number_of_style_images +
1, :, :, :]
loss = list()
for j in range(number_of_style_images):
if style_mask_tensor_list is None:
loss.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=None,
content_mask=content_mask_tensor))
else:
loss.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=style_mask_tensor_list[j],
content_mask=content_mask_tensor))
layer_features = features[style_layer_names[i + 1]]
style_features = layer_features[1:(number_of_style_images +
1), :, :, :]
combination_features = layer_features[number_of_style_images +
1, :, :, :]
loss_p1 = list()
for j in range(number_of_style_images):
if style_mask_tensor_list is None:
loss_p1.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=None,
content_mask=content_mask_tensor))
else:
loss_p1.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=style_mask_tensor_list[j],
content_mask=content_mask_tensor))
for j in range(number_of_style_images):
loss_difference = loss[j] - loss_p1[j]
total_loss = total_loss + (style_image_weights[j] *
loss_difference /
(2**(len(style_layer_names) -
(i + 1))))
else:
for i in range(len(style_layer_names)):
layer_features = features[style_layer_names[i]]
style_features = layer_features[1:(number_of_style_images +
1), :, :, :]
combination_features = layer_features[number_of_style_images +
1, :, :, :]
for j in range(number_of_style_images):
loss = list()
if style_mask_tensor_list is None:
loss.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=None,
content_mask=content_mask_tensor))
else:
loss.append(
style_loss(style_features[j],
combination_features,
image_shape,
style_mask=style_mask_tensor_list[j],
content_mask=content_mask_tensor))
for j in range(number_of_style_images):
total_loss = total_loss + (loss[j] * style_image_weights[j]
/ len(style_layer_names))
# total variation loss
total_loss = total_loss + total_variation_weight * total_variation_loss(
combination_tensor)
return (total_loss)
def compute_loss_and_gradients(content_array,
style_array_list,
combination_tensor,
feature_model,
content_layer_names,
style_layer_names,
image_shape,
content_mask_tensor=None,
style_mask_tensor_list=None):
with tf.GradientTape() as tape:
loss = compute_total_loss(content_array, style_array_list,
combination_tensor, feature_model,
content_layer_names, style_layer_names,
image_shape, content_mask_tensor,
style_mask_tensor_list)
gradients = tape.gradient(loss, combination_tensor)
return loss, gradients
number_of_style_images = 1
if isinstance(style_images, list):
number_of_style_images = len(style_images)
style_image_list = list()
if number_of_style_images == 1:
style_image_list.append(style_images)
else:
style_image_list = style_images
for i in range(number_of_style_images):
if style_image_list[i].dimension != 2:
raise ValueError("Input style images must be 2-D.")
if style_image_list[i].shape != content_image.shape:
raise ValueError(
"Input images must have matching dimensions/shapes.")
number_of_style_masks = 0
style_mask_tensor_list = None
if style_masks is not None:
number_of_style_masks = 1
if isinstance(style_masks, list):
number_of_style_masks = len(style_masks)
style_mask_tensor_list = list()
if number_of_style_masks == 1:
style_mask_array = (ants.threshold_image(style_masks, 0, 0, 0,
1)).numpy()
style_mask_tensor = np.expand_dims(style_mask_array, -1)
style_mask_tensor_list.append(style_mask_tensor)
else:
for i in range(len(style_masks)):
style_mask_array = (ants.threshold_image(
style_masks[i], 0, 0, 0, 1)).numpy()
style_mask_tensor = np.expand_dims(style_mask_array, -1)
style_mask_tensor_list.append(style_mask_tensor)
if number_of_style_masks > 0 and number_of_style_images != number_of_style_masks:
raise ValueError("The number of style images/masks are not the same.")
if isinstance(style_image_weights, (int, float)):
style_image_weights = [style_image_weights] * len(style_image_list)
else:
if len(style_image_weights) == 1:
style_image_weights = style_image_weights * len(style_image_list)
elif not len(style_image_weights) == len(style_image_list):
raise ValueError(
"Length of style weights must be 1 or the number of style images."
)
if content_image.dimension != 2:
raise ValueError("Input content image must be 2-D.")
content_mask_tensor = None
if content_mask is not None:
content_mask_array = (ants.threshold_image(content_mask, 0, 0, 0,
1)).numpy()
content_mask_tensor = np.expand_dims(content_mask_array, -1)
if style_layer_names == "all":
style_layer_names = [
'block1_conv1', 'block1_conv2', 'block2_conv1', 'block2_conv2',
'block3_conv1', 'block3_conv2', 'block3_conv3', 'block3_conv4',
'block4_conv1', 'block4_conv2', 'block4_conv3', 'block4_conv4',
'block5_conv1', 'block5_conv2', 'block5_conv3', 'block5_conv4'
]
model = vgg19.VGG19(weights="imagenet", include_top=False)
outputs_dictionary = dict([(layer.name, layer.output)
for layer in model.layers])
# shapes_dictionary = dict([(layer.name, layer.output_shape) for layer in model.layers])
feature_model = tf.keras.Model(inputs=model.inputs,
outputs=outputs_dictionary)
# Preprocess data
content_array = preprocess_ants_image(content_image)
style_array_list = list()
for i in range(number_of_style_images):
style_array_list.append(preprocess_ants_image(style_image_list[i]))
image_shape = (content_array.shape[1], content_array.shape[2], 3)
combination_tensor = None
if initial_combination_image is None:
combination_tensor = tf.Variable(np.copy(content_array))
else:
initial_combination_tensor = preprocess_ants_image(
initial_combination_image, do_scale_and_center=False)
combination_tensor = tf.Variable(initial_combination_tensor)
if not image_shape == (combination_tensor.shape[1],
combination_tensor.shape[2], 3):
raise ValueError(
"Initial combination image size does not match content image.")
optimizer = tf.optimizers.Adam(learning_rate=learning_rate,
beta_1=0.99,
epsilon=0.1)
for i in range(number_of_iterations):
start_time = time.time()
loss, gradients = compute_loss_and_gradients(
content_array, style_array_list, combination_tensor, feature_model,
content_layer_names, style_layer_names, image_shape,
content_mask_tensor, style_mask_tensor_list)
end_time = time.time()
if verbose == True:
print(
"Iteration %d of %d: total loss = %.2f (elapsed time = %ds)" %
(i, number_of_iterations, loss, end_time - start_time))
optimizer.apply_gradients([(gradients, combination_tensor)])
if not output_prefix == None:
combination_array = combination_tensor.numpy()
combination_image = postprocess_array(combination_array,
content_image)
combination_rgb = combination_image.vector_to_rgb()
ants.image_write(combination_rgb,
output_prefix + "_iteration%d.png" % (i + 1))
combination_array = combination_tensor.numpy()
combination_image = postprocess_array(combination_array, content_image)
return (combination_image)
with open(target_file_image_name, 'wb') as f:
f.write(r.content)
image = ants.image_read(target_file_image_name)
print("Preprocessing: bias correction")
image_n4 = ants.n4_bias_field_correction(image)
image_n4 = ants.image_math(image_n4, 'Normalize') * 255.0
print("Preprocessing: thresholding")
image_n4_array = ((image_n4.numpy()).flatten())
image_n4_nonzero = image_n4_array[(image_n4_array > 0).nonzero()]
image_robust_range = np.quantile(image_n4_nonzero, (0.02, 0.98))
threshold_value = 0.10 * (image_robust_range[1] -
image_robust_range[0]) + image_robust_range[0]
thresholded_mask = ants.threshold_image(image_n4, -10000, threshold_value, 0,
1)
thresholded_image = image_n4 * thresholded_mask
print("Preprocessing: resampling")
image_resampled = ants.resample_image(thresholded_image, (256, 256, 256), True)
batchX = np.expand_dims(image_resampled.numpy(), axis=0)
batchX = np.expand_dims(batchX, axis=-1)
print("Prediction and write to disk.")
brain_mask_array = model.predict(batchX, verbose=0)
brain_mask_resampled = ants.from_numpy(np.squeeze(brain_mask_array[0, :, :, :,
0]),
origin=image_resampled.origin,
spacing=image_resampled.spacing,
direction=image_resampled.direction)
brain_mask_image = ants.resample_image(brain_mask_resampled, image.shape, True,
print(" Initial step 1: bias correction.")
start_time = time.time()
image_n4 = warped_image # ants.n4_bias_field_correction(warped_image)
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
# Threshold at 10th percentile of non-zero voxels in "robust range (fslmaths)"
print(" Initial step 2: threshold.")
start_time = time.time()
image_n4_array = ((image_n4.numpy()).flatten())
image_n4_nonzero = image_n4_array[(image_n4_array > 0).nonzero()]
image_robust_range = np.quantile(image_n4_nonzero, (0.02, 0.98))
threshold_value = 0.10 * (image_robust_range[1] -
image_robust_range[0]) + image_robust_range[0]
thresholded_mask = ants.threshold_image(image_n4, -10000, threshold_value, 0,
1)
thresholded_image = image_n4 * thresholded_mask
end_time = time.time()
elapsed_time = end_time - start_time
print(" (elapsed time: ", elapsed_time, " seconds)")
# Standardize image (should do patch-based stuff but making a quicker substitute for testing)
print(" Initial step 3: standardize.")
start_time = time.time()
thresholded_array = ((thresholded_image.numpy()).flatten())
thresholded_nonzero = image_n4_array[(thresholded_array > 0).nonzero()]
image_mean = np.mean(thresholded_nonzero)
image_sd = np.std(thresholded_nonzero)
image_standard = (image_n4 - image_mean) / image_sd
image_standard = image_standard * thresholded_mask
end_time = time.time()
####################
#
# Run longitudinal cortical thickness
#
####################
kk_long = antspynet.longitudinal_cortical_thickness(t1s, initial_template="adni",
number_of_iterations=2, refinement_transform="antsRegistrationSyNQuick[a]", verbose=True)
sst_file = output_directory + "/" + "SingleSubjectTemplate.nii.gz"
ants.image_write(kk_long[-1], sst_file)
for i in range(len(t1s)):
kk_file = output_directory + "/" + t1s_basename_prefix[i] + "CorticalThickness.nii.gz"
ants.image_write(kk_long[i]['thickness_image'], kk_file)
t1_pre_file = output_directory + "/" + t1s_basename_prefix[i] + "Preprocessed.nii.gz"
ants.image_write(kk_long[i]['preprocessed_image'], t1_pre_file)
dkt_file = output_directory + "/" + t1s_basename_prefix[i] + "DktLabels.nii.gz"
dkt = antspynet.desikan_killiany_tourville_labeling(kk_long[i]['preprocessed_image'], do_preprocessing=True, verbose=True)
ants.image_write(dkt, dkt_file)
dkt_prop_file = output_directory + "/" + t1s_basename_prefix[i] + "DktPropagatedLabels.nii.gz"
dkt_mask = ants.threshold_image(dkt, 1000, 3000, 1, 0)
dkt = dkt_mask * dkt
ants_tmp = ants.threshold_image(kk_long[i]['thickness_image'], 0, 0, 0, 1)
ants_dkt = ants.iMath(ants_tmp, "PropagateLabelsThroughMask", ants_tmp * dkt)
ants.image_write(ants_dkt, dkt_prop_file)
def test_image_to_cluster_images_example(self):
image = ants.image_read(ants.get_ants_data('r16'))
image = ants.threshold_image(image, 1, 1e15)
image_cluster_list = ants.image_to_cluster_images(image)
def claustrum_segmentation(t1,
do_preprocessing=True,
use_ensemble=True,
antsxnet_cache_directory=None,
verbose=False):
"""
Claustrum segmentation
Described here:
https://arxiv.org/abs/2008.03465
with the implementation available at:
https://github.com/hongweilibran/claustrum_multi_view
Arguments
---------
t1 : ANTsImage
input 3-D T1 brain image.
do_preprocessing : boolean
perform n4 bias correction.
use_ensemble : boolean
check whether to use all 3 sets of weights.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
Claustrum segmentation probability image
Example
-------
>>> image = ants.image_read("t1.nii.gz")
>>> probability_mask = claustrum_segmentation(image)
"""
from ..architectures import create_sysu_media_unet_model_2d
from ..utilities import brain_extraction
from ..utilities import get_pretrained_network
from ..utilities import preprocess_brain_image
from ..utilities import pad_or_crop_image_to_size
if t1.dimension != 3:
raise ValueError("Image dimension must be 3.")
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
image_size = (180, 180)
################################
#
# Preprocess images
#
################################
number_of_channels = 1
t1_preprocessed = ants.image_clone(t1)
brain_mask = ants.threshold_image(t1, 0, 0, 0, 1)
if do_preprocessing == True:
t1_preprocessing = preprocess_brain_image(
t1,
truncate_intensity=(0.01, 0.99),
brain_extraction_modality="t1",
do_bias_correction=True,
do_denoising=True,
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
t1_preprocessed = t1_preprocessing["preprocessed_image"]
brain_mask = t1_preprocessing["brain_mask"]
reference_image = ants.make_image((170, 256, 256),
voxval=1,
spacing=(1, 1, 1),
origin=(0, 0, 0),
direction=np.identity(3))
center_of_mass_reference = ants.get_center_of_mass(reference_image)
center_of_mass_image = ants.get_center_of_mass(brain_mask)
translation = np.asarray(center_of_mass_image) - np.asarray(
center_of_mass_reference)
xfrm = ants.create_ants_transform(
transform_type="Euler3DTransform",
center=np.asarray(center_of_mass_reference),
translation=translation)
t1_preprocessed_warped = ants.apply_ants_transform_to_image(
xfrm, t1_preprocessed, reference_image)
brain_mask_warped = ants.threshold_image(
ants.apply_ants_transform_to_image(xfrm, brain_mask, reference_image),
0.5, 1.1, 1, 0)
################################
#
# Gaussian normalize intensity based on brain mask
#
################################
mean_t1 = t1_preprocessed_warped[brain_mask_warped > 0].mean()
std_t1 = t1_preprocessed_warped[brain_mask_warped > 0].std()
t1_preprocessed_warped = (t1_preprocessed_warped - mean_t1) / std_t1
t1_preprocessed_warped = t1_preprocessed_warped * brain_mask_warped
################################
#
# Build models and load weights
#
################################
number_of_models = 1
if use_ensemble == True:
number_of_models = 3
if verbose == True:
print("Claustrum: retrieving axial model weights.")
unet_axial_models = list()
for i in range(number_of_models):
weights_file_name = get_pretrained_network(
"claustrum_axial_" + str(i),
antsxnet_cache_directory=antsxnet_cache_directory)
unet_axial_models.append(
create_sysu_media_unet_model_2d((*image_size, number_of_channels),
anatomy="claustrum"))
unet_axial_models[i].load_weights(weights_file_name)
if verbose == True:
print("Claustrum: retrieving coronal model weights.")
unet_coronal_models = list()
for i in range(number_of_models):
weights_file_name = get_pretrained_network(
"claustrum_coronal_" + str(i),
antsxnet_cache_directory=antsxnet_cache_directory)
unet_coronal_models.append(
create_sysu_media_unet_model_2d((*image_size, number_of_channels),
anatomy="claustrum"))
unet_coronal_models[i].load_weights(weights_file_name)
################################
#
# Extract slices
#
################################
dimensions_to_predict = [1, 2]
batch_coronal_X = np.zeros(
(t1_preprocessed_warped.shape[1], *image_size, number_of_channels))
batch_axial_X = np.zeros(
(t1_preprocessed_warped.shape[2], *image_size, number_of_channels))
for d in range(len(dimensions_to_predict)):
number_of_slices = t1_preprocessed_warped.shape[
dimensions_to_predict[d]]
if verbose == True:
print("Extracting slices for dimension ", dimensions_to_predict[d],
".")
for i in range(number_of_slices):
t1_slice = pad_or_crop_image_to_size(
ants.slice_image(t1_preprocessed_warped,
dimensions_to_predict[d], i), image_size)
if dimensions_to_predict[d] == 1:
batch_coronal_X[i, :, :, 0] = np.rot90(t1_slice.numpy(), k=-1)
else:
batch_axial_X[i, :, :, 0] = np.rot90(t1_slice.numpy())
################################
#
# Do prediction and then restack into the image
#
################################
if verbose == True:
print("Coronal prediction.")
prediction_coronal = unet_coronal_models[0].predict(batch_coronal_X,
verbose=verbose)
if number_of_models > 1:
for i in range(1, number_of_models, 1):
prediction_coronal += unet_coronal_models[i].predict(
batch_coronal_X, verbose=verbose)
prediction_coronal /= number_of_models
for i in range(t1_preprocessed_warped.shape[1]):
prediction_coronal[i, :, :, 0] = np.rot90(
np.squeeze(prediction_coronal[i, :, :, 0]))
if verbose == True:
print("Axial prediction.")
prediction_axial = unet_axial_models[0].predict(batch_axial_X,
verbose=verbose)
if number_of_models > 1:
for i in range(1, number_of_models, 1):
prediction_axial += unet_axial_models[i].predict(batch_axial_X,
verbose=verbose)
prediction_axial /= number_of_models
for i in range(t1_preprocessed_warped.shape[2]):
prediction_axial[i, :, :,
0] = np.rot90(np.squeeze(prediction_axial[i, :, :,
0]),
k=-1)
if verbose == True:
print("Restack image and transform back to native space.")
permutations = list()
permutations.append((0, 1, 2))
permutations.append((1, 0, 2))
permutations.append((1, 2, 0))
prediction_image_average = ants.image_clone(t1_preprocessed_warped) * 0
for d in range(len(dimensions_to_predict)):
which_batch_slices = range(
t1_preprocessed_warped.shape[dimensions_to_predict[d]])
prediction_per_dimension = None
if dimensions_to_predict[d] == 1:
prediction_per_dimension = prediction_coronal[
which_batch_slices, :, :, :]
else:
prediction_per_dimension = prediction_axial[
which_batch_slices, :, :, :]
prediction_array = np.transpose(np.squeeze(prediction_per_dimension),
permutations[dimensions_to_predict[d]])
prediction_image = ants.copy_image_info(
t1_preprocessed_warped,
pad_or_crop_image_to_size(ants.from_numpy(prediction_array),
t1_preprocessed_warped.shape))
prediction_image_average = prediction_image_average + (
prediction_image - prediction_image_average) / (d + 1)
probability_image = ants.apply_ants_transform_to_image(
ants.invert_ants_transform(xfrm), prediction_image_average,
t1) * ants.threshold_image(brain_mask, 0.5, 1, 1, 0)
return (probability_image)
def preprocess_brain_image(image,
truncate_intensity=(0.01, 0.99),
brain_extraction_modality=None,
template_transform_type=None,
template="biobank",
do_bias_correction=True,
return_bias_field=False,
do_denoising=True,
intensity_matching_type=None,
reference_image=None,
intensity_normalization_type=None,
antsxnet_cache_directory=None,
verbose=True):
"""
Basic preprocessing pipeline for T1-weighted brain MRI
Standard preprocessing steps that have been previously described
in various papers including the cortical thickness pipeline:
https://www.ncbi.nlm.nih.gov/pubmed/24879923
Arguments
---------
image : ANTsImage
input image
truncate_intensity : 2-length tuple
Defines the quantile threshold for truncating the image intensity
brain_extraction_modality : string or None
Perform brain extraction using antspynet tools. One of "t1", "t1v0",
"t1nobrainer", "t1combined", "flair", "t2", "bold", "fa", "t1infant",
"t2infant", or None.
template_transform_type : string
See details in help for ants.registration. Typically "Rigid" or
"Affine".
template : ANTs image (not skull-stripped)
Alternatively, one can specify the default "biobank" or "croppedMni152"
to download and use premade templates.
do_bias_correction : boolean
Perform N4 bias field correction.
return_bias_field : boolean
If True, return bias field as an additional output *without* bias
correcting the preprocessed image.
do_denoising : boolean
Perform non-local means denoising.
intensity_matching_type : string
Either "regression" or "histogram". Only is performed if reference_image
is not None.
reference_image : ANTs image
Reference image for intensity matching.
intensity_normalization_type : string
Either rescale the intensities to [0,1] (i.e., "01") or zero-mean, unit variance
(i.e., "0mean"). If None normalization is not performed.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
Dictionary with preprocessing information ANTs image (i.e., source_image) matched to the
(reference_image).
Example
-------
>>> import ants
>>> image = ants.image_read(ants.get_ants_data('r16'))
>>> preprocessed_image = preprocess_brain_image(image, do_brain_extraction=False)
"""
from ..utilities import brain_extraction
from ..utilities import regression_match_image
from ..utilities import get_antsxnet_data
preprocessed_image = ants.image_clone(image)
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
# Truncate intensity
if truncate_intensity is not None:
quantiles = (image.quantile(truncate_intensity[0]), image.quantile(truncate_intensity[1]))
if verbose == True:
print("Preprocessing: truncate intensities ( low =", quantiles[0], ", high =", quantiles[1], ").")
preprocessed_image[image < quantiles[0]] = quantiles[0]
preprocessed_image[image > quantiles[1]] = quantiles[1]
# Brain extraction
mask = None
if brain_extraction_modality is not None:
if verbose == True:
print("Preprocessing: brain extraction.")
probability_mask = brain_extraction(preprocessed_image, modality=brain_extraction_modality,
antsxnet_cache_directory=antsxnet_cache_directory, verbose=verbose)
mask = ants.threshold_image(probability_mask, 0.5, 1, 1, 0)
mask = ants.morphology(mask,"close",6).iMath_fill_holes()
# Template normalization
transforms = None
if template_transform_type is not None:
template_image = None
if isinstance(template, str):
template_file_name_path = get_antsxnet_data(template, antsxnet_cache_directory=antsxnet_cache_directory)
template_image = ants.image_read(template_file_name_path)
else:
template_image = template
if mask is None:
registration = ants.registration(fixed=template_image, moving=preprocessed_image,
type_of_transform=template_transform_type, verbose=verbose)
preprocessed_image = registration['warpedmovout']
transforms = dict(fwdtransforms=registration['fwdtransforms'],
invtransforms=registration['invtransforms'])
else:
template_probability_mask = brain_extraction(template_image, modality=brain_extraction_modality,
antsxnet_cache_directory=antsxnet_cache_directory, verbose=verbose)
template_mask = ants.threshold_image(template_probability_mask, 0.5, 1, 1, 0)
template_brain_image = template_mask * template_image
preprocessed_brain_image = preprocessed_image * mask
registration = ants.registration(fixed=template_brain_image, moving=preprocessed_brain_image,
type_of_transform=template_transform_type, verbose=verbose)
transforms = dict(fwdtransforms=registration['fwdtransforms'],
invtransforms=registration['invtransforms'])
preprocessed_image = ants.apply_transforms(fixed = template_image, moving = preprocessed_image,
transformlist=registration['fwdtransforms'], interpolator="linear", verbose=verbose)
mask = ants.apply_transforms(fixed = template_image, moving = mask,
transformlist=registration['fwdtransforms'], interpolator="genericLabel", verbose=verbose)
# Do bias correction
bias_field = None
if do_bias_correction == True:
if verbose == True:
print("Preprocessing: brain correction.")
n4_output = None
if mask is None:
n4_output = ants.n4_bias_field_correction(preprocessed_image, shrink_factor=4, return_bias_field=return_bias_field, verbose=verbose)
else:
n4_output = ants.n4_bias_field_correction(preprocessed_image, mask, shrink_factor=4, return_bias_field=return_bias_field, verbose=verbose)
if return_bias_field == True:
bias_field = n4_output
else:
preprocessed_image = n4_output
# Denoising
if do_denoising == True:
if verbose == True:
print("Preprocessing: denoising.")
if mask is None:
preprocessed_image = ants.denoise_image(preprocessed_image, shrink_factor=1)
else:
preprocessed_image = ants.denoise_image(preprocessed_image, mask, shrink_factor=1)
# Image matching
if reference_image is not None and intensity_matching_type is not None:
if verbose == True:
print("Preprocessing: intensity matching.")
if intensity_matching_type == "regression":
preprocessed_image = regression_match_image(preprocessed_image, reference_image)
elif intensity_matching_type == "histogram":
preprocessed_image = ants.histogram_match_image(preprocessed_image, reference_image)
else:
raise ValueError("Unrecognized intensity_matching_type.")
# Intensity normalization
if intensity_normalization_type is not None:
if verbose == True:
print("Preprocessing: intensity normalization.")
if intensity_normalization_type == "01":
preprocessed_image = (preprocessed_image - preprocessed_image.min())/(preprocessed_image.max() - preprocessed_image.min())
elif intensity_normalization_type == "0mean":
preprocessed_image = (preprocessed_image - preprocessed_image.mean())/preprocessed_image.std()
else:
raise ValueError("Unrecognized intensity_normalization_type.")
return_dict = {'preprocessed_image' : preprocessed_image}
if mask is not None:
return_dict['brain_mask'] = mask
if bias_field is not None:
return_dict['bias_field'] = bias_field
if transforms is not None:
return_dict['template_transforms'] = transforms
return(return_dict)
import tensorflow as tf
t1_file = sys.argv[1]
output_prefix = sys.argv[2]
threads = int(sys.argv[3])
tf.keras.backend.clear_session()
config = tf.compat.v1.ConfigProto(intra_op_parallelism_threads=threads,
inter_op_parallelism_threads=threads)
session = tf.compat.v1.Session(config=config)
tf.compat.v1.keras.backend.set_session(session)
t1 = ants.image_read(t1_file)
kk = ants.image_read(output_prefix + "CorticalThickness.nii.gz")
# If one wants cortical labels one can run the following lines
dkt = antspynet.desikan_killiany_tourville_labeling(t1,
do_preprocessing=True,
verbose=True)
ants.image_write(dkt, output_prefix + "Dkt.nii.gz")
dkt_mask = ants.threshold_image(dkt, 1000, 3000, 1, 0)
dkt = dkt_mask * dkt
ants_tmp = ants.threshold_image(kk, 0, 0, 0, 1)
ants_dkt = ants.iMath(ants_tmp, "PropagateLabelsThroughMask", ants_tmp * dkt)
ants.image_write(ants_dkt, output_prefix + "DktPropagatedLabels.nii.gz")
#
pts2bold = ants.apply_transforms_to_points( 3, powers_areal_mni_itk, concatx2,whichtoinvert = ( True, False, True, False ) )
locations = pts2bold.iloc[:,:3].values
ptImg = ants.make_points_image( locations, bmask, radius = 3 )
networks = powers_areal_mni_itk['SystemName'].unique()
dfnpts = np.where( powers_areal_mni_itk['SystemName'] == networks[5] )
dfnImg = ants.mask_image( ptImg, ptImg, level = dfnpts[0].tolist(), binarize=False )
# plot( und, ptImg, axis=3, window.overlay = range( ptImg ) )
bold2ch2 = ants.apply_transforms( ch2, und, concatx2, whichtoinvert = ( True, False, True, False ) )
# Extracting canonical functional network maps
## preprocessing
csfAndWM = ( ants.threshold_image( boldseg, 1, 1 ) +
ants.threshold_image( boldseg, 3, 3 ) ).morphology("erode",1)
bold = ants.image_read( boldfnsR )
boldList = ants.ndimage_to_list( bold )
avgBold = ants.get_average_of_timeseries( bold, range( 5 ) )
boldUndTX = ants.registration( und, avgBold, "SyN", regIterations = (15,4),
synMetric = "CC", synSampling = 2, verbose = False )
boldUndTS = ants.apply_transforms( und, bold, boldUndTX['fwdtransforms'], imagetype = 3 )
motCorr = ants.motion_correction( boldUndTS, avgBold,
type_of_transform="Rigid", verbose = True )
tr = ants.get_spacing( bold )[3]
highMotionTimes = np.where( motCorr['FD'] >= 0.5 )
goodtimes = np.where( motCorr['FD'] < 0.5 )
avgBold = ants.get_average_of_timeseries( motCorr['motion_corrected'], range( 5 ) )
#######################
nt = len(motCorr['FD'])
def brain_extraction(image,
modality="t1",
antsxnet_cache_directory=None,
verbose=False):
"""
Perform brain extraction using U-net and ANTs-based training data. "NoBrainer"
is also possible where brain extraction uses U-net and FreeSurfer training data
ported from the
https://github.com/neuronets/nobrainer-models
Arguments
---------
image : ANTsImage
input image (or list of images for multi-modal scenarios).
modality : string
Modality image type. Options include:
* "t1": T1-weighted MRI---ANTs-trained. Update from "t1v0".
* "t1v0": T1-weighted MRI---ANTs-trained.
* "t1nobrainer": T1-weighted MRI---FreeSurfer-trained: h/t Satra Ghosh and Jakub Kaczmarzyk.
* "t1combined": Brian's combination of "t1" and "t1nobrainer". One can also specify
"t1combined[X]" where X is the morphological radius. X = 12 by default.
* "flair": FLAIR MRI.
* "t2": T2 MRI.
* "bold": 3-D BOLD MRI.
* "fa": Fractional anisotropy.
* "t1t2infant": Combined T1-w/T2-w infant MRI h/t Martin Styner.
* "t1infant": T1-w infant MRI h/t Martin Styner.
* "t2infant": T2-w infant MRI h/t Martin Styner.
antsxnet_cache_directory : string
Destination directory for storing the downloaded template and model weights.
Since these can be resused, if is None, these data will be downloaded to a
~/.keras/ANTsXNet/.
verbose : boolean
Print progress to the screen.
Returns
-------
ANTs probability brain mask image.
Example
-------
>>> probability_brain_mask = brain_extraction(brain_image, modality="t1")
"""
from ..architectures import create_unet_model_3d
from ..utilities import get_pretrained_network
from ..utilities import get_antsxnet_data
from ..architectures import create_nobrainer_unet_model_3d
classes = ("background", "brain")
number_of_classification_labels = len(classes)
channel_size = 1
if isinstance(image, list):
channel_size = len(image)
if antsxnet_cache_directory == None:
antsxnet_cache_directory = "ANTsXNet"
input_images = list()
if channel_size == 1:
input_images.append(image)
else:
input_images = image
if input_images[0].dimension != 3:
raise ValueError("Image dimension must be 3.")
if "t1combined" in modality:
brain_extraction_t1 = brain_extraction(
image,
modality="t1",
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
brain_mask = ants.iMath_get_largest_component(
ants.threshold_image(brain_extraction_t1, 0.5, 10000))
# Need to change with voxel resolution
morphological_radius = 12
if '[' in modality and ']' in modality:
morphological_radius = int(modality.split("[")[1].split("]")[0])
brain_extraction_t1nobrainer = brain_extraction(
image * ants.iMath_MD(brain_mask, radius=morphological_radius),
modality="t1nobrainer",
antsxnet_cache_directory=antsxnet_cache_directory,
verbose=verbose)
brain_extraction_combined = ants.iMath_fill_holes(
ants.iMath_get_largest_component(brain_extraction_t1nobrainer *
brain_mask))
brain_extraction_combined = brain_extraction_combined + ants.iMath_ME(
brain_mask, morphological_radius) + brain_mask
return (brain_extraction_combined)
if modality != "t1nobrainer":
#####################
#
# ANTs-based
#
#####################
weights_file_name_prefix = None
if modality == "t1v0":
weights_file_name_prefix = "brainExtraction"
elif modality == "t1":
weights_file_name_prefix = "brainExtractionT1"
elif modality == "t2":
weights_file_name_prefix = "brainExtractionT2"
elif modality == "flair":
weights_file_name_prefix = "brainExtractionFLAIR"
elif modality == "bold":
weights_file_name_prefix = "brainExtractionBOLD"
elif modality == "fa":
weights_file_name_prefix = "brainExtractionFA"
elif modality == "t1t2infant":
weights_file_name_prefix = "brainExtractionInfantT1T2"
elif modality == "t1infant":
weights_file_name_prefix = "brainExtractionInfantT1"
elif modality == "t2infant":
weights_file_name_prefix = "brainExtractionInfantT2"
else:
raise ValueError("Unknown modality type.")
weights_file_name = get_pretrained_network(
weights_file_name_prefix,
antsxnet_cache_directory=antsxnet_cache_directory)
if verbose == True:
print("Brain extraction: retrieving template.")
reorient_template_file_name_path = get_antsxnet_data(
"S_template3", antsxnet_cache_directory=antsxnet_cache_directory)
reorient_template = ants.image_read(reorient_template_file_name_path)
resampled_image_size = reorient_template.shape
if modality == "t1":
classes = ("background", "head", "brain")
number_of_classification_labels = len(classes)
unet_model = create_unet_model_3d(
(*resampled_image_size, channel_size),
number_of_outputs=number_of_classification_labels,
number_of_layers=4,
number_of_filters_at_base_layer=8,
dropout_rate=0.0,
convolution_kernel_size=(3, 3, 3),
deconvolution_kernel_size=(2, 2, 2),
weight_decay=1e-5)
unet_model.load_weights(weights_file_name)
if verbose == True:
print("Brain extraction: normalizing image to the template.")
center_of_mass_template = ants.get_center_of_mass(reorient_template)
center_of_mass_image = ants.get_center_of_mass(input_images[0])
translation = np.asarray(center_of_mass_image) - np.asarray(
center_of_mass_template)
xfrm = ants.create_ants_transform(
transform_type="Euler3DTransform",
center=np.asarray(center_of_mass_template),
translation=translation)
batchX = np.zeros((1, *resampled_image_size, channel_size))
for i in range(len(input_images)):
warped_image = ants.apply_ants_transform_to_image(
xfrm, input_images[i], reorient_template)
warped_array = warped_image.numpy()
batchX[0, :, :, :, i] = (warped_array -
warped_array.mean()) / warped_array.std()
if verbose == True:
print("Brain extraction: prediction and decoding.")
predicted_data = unet_model.predict(batchX, verbose=verbose)
origin = reorient_template.origin
spacing = reorient_template.spacing
direction = reorient_template.direction
probability_images_array = list()
probability_images_array.append(
ants.from_numpy(np.squeeze(predicted_data[0, :, :, :, 0]),
origin=origin,
spacing=spacing,
direction=direction))
probability_images_array.append(
ants.from_numpy(np.squeeze(predicted_data[0, :, :, :, 1]),
origin=origin,
spacing=spacing,
direction=direction))
if modality == "t1":
probability_images_array.append(
ants.from_numpy(np.squeeze(predicted_data[0, :, :, :, 2]),
origin=origin,
spacing=spacing,
direction=direction))
if verbose == True:
print(
"Brain extraction: renormalize probability mask to native space."
)
probability_image = ants.apply_ants_transform_to_image(
ants.invert_ants_transform(xfrm),
probability_images_array[number_of_classification_labels - 1],
input_images[0])
return (probability_image)
else:
#####################
#
# NoBrainer
#
#####################
if verbose == True:
print("NoBrainer: generating network.")
model = create_nobrainer_unet_model_3d((None, None, None, 1))
weights_file_name = get_pretrained_network(
"brainExtractionNoBrainer",
antsxnet_cache_directory=antsxnet_cache_directory)
model.load_weights(weights_file_name)
if verbose == True:
print(
"NoBrainer: preprocessing (intensity truncation and resampling)."
)
image_array = image.numpy()
image_robust_range = np.quantile(
image_array[np.where(image_array != 0)], (0.02, 0.98))
threshold_value = 0.10 * (image_robust_range[1] - image_robust_range[0]
) + image_robust_range[0]
thresholded_mask = ants.threshold_image(image, -10000, threshold_value,
0, 1)
thresholded_image = image * thresholded_mask
image_resampled = ants.resample_image(thresholded_image,
(256, 256, 256),
use_voxels=True)
image_array = np.expand_dims(image_resampled.numpy(), axis=0)
image_array = np.expand_dims(image_array, axis=-1)
if verbose == True:
print("NoBrainer: predicting mask.")
brain_mask_array = np.squeeze(
model.predict(image_array, verbose=verbose))
brain_mask_resampled = ants.copy_image_info(
image_resampled, ants.from_numpy(brain_mask_array))
brain_mask_image = ants.resample_image(brain_mask_resampled,
image.shape,
use_voxels=True,
interp_type=1)
spacing = ants.get_spacing(image)
spacing_product = spacing[0] * spacing[1] * spacing[2]
minimum_brain_volume = round(649933.7 / spacing_product)
brain_mask_labeled = ants.label_clusters(brain_mask_image,
minimum_brain_volume)
return (brain_mask_labeled)
