def brainsuite_susceptibility_correction(outdir,
dwi,
bval,
bvec,
subject_id,
phase_enc_dir,
subjects_dir=None,
qc_dir=None,
bdp_nthread=4):
"""
Assuming the beginning of the preprocessing was done with Connectomist
up to Eddy current and motion correction, we now want to make susceptbility
distortion correction using Brainsuite.
Parameters
----------
outdir: str
Path to directory where to output.
dwi: str
Path to the preprocessed diffusion-weighted Nifti.
bval: str
Path to the bval file associated to the Nifti.
bvec: str
Path to the bvec file associated to the Nifti.
subject_id: str
Subject identifier used in Freesurfer.
phase_enc_dir: str
In plane phase encoding direction, "y", "y-", "x" or "x-".
subjects_dir: str, default None
If the Freesurfer $SUBJECTS_DIR environment variable is not set, or to
bypass it, pass the path.
qc_dir: str, default None
Path to directory where to output snapshots for QC. By default in
outdir.
bdp_nthread: int, default 4
Number of threads for bdp (see bdp.sh --thread flag)
"""
# Freesurfer 'subjects_dir' has to be passed or set as environment variable
subjects_dir = get_or_check_freesurfer_subjects_dir(subjects_dir)
# Check in plane phase encoding direction
# The sign of the phase encoding direction has no impact in this strategy
# e.g. for "+y" or "-y" use "y"
possible_phase_enc_dirs = {"y", "x"}
if phase_enc_dir not in possible_phase_enc_dirs:
raise ValueError(
"Bad argument 'phase_enc_dir': {}, should be in {}.".format(
phase_enc_dir, possible_phase_enc_dirs))
# Set and check path to T1 brain-only volume from Freesurfer (mgz format)
t1_brain_mgz = os.path.join(subjects_dir, subject_id, "mri/brain.mgz")
if not os.path.isfile(t1_brain_mgz):
raise Exception("Missing file: {}".format(t1_brain_mgz))
# Convert Freesurfer T1 to Nifti with reorientation to RAS (to be in the
# same orientation as the diffusion data)
t1_brain_RAS_nii = os.path.join(outdir, "t1_brain.nii.gz")
cmd = [
"mri_convert", t1_brain_mgz, t1_brain_RAS_nii, "--out_orientation",
"RAS"
]
run_freesurfer_cmd(cmd, subjects_dir=subjects_dir)
# Run bfc (bias correction: required by BrainSuite)
t1_bfc = os.path.join(outdir, "t1_brain.bfc.nii.gz")
cmd = ["bfc", "-i", t1_brain_RAS_nii, "-o", t1_bfc]
subprocess.check_call(cmd)
# Extract brain from the nodif volume with FSL bet2
nodif_brain = os.path.join(outdir, "nodif_brain.nii.gz")
bet2(dwi, nodif_brain, f=0.25, m=False)
# Run bdp.sh: registration + diffusion model
cmd = [
"bdp.sh", t1_bfc, "--nii", dwi, "--bval", bval, "--bvec", bvec,
"--dwi-mask", nodif_brain,
"--dir=%s" % phase_enc_dir,
"--threads=%i" % bdp_nthread
]
subprocess.check_call(cmd)
# Path to files of interest, created by BrainSuite bdp.sh
dwi_wo_susceptibility = os.path.join(outdir,
"t1_brain.dwi.RAS.correct.nii.gz")
###############
# Quality check: create snapshots to visually assert the registration
# quality
if qc_dir is None:
qc_dir = outdir
# The snapshots won't contain all slices, half of them
nb_slices_in_z = nibabel.load(nodif_brain).get_shape()[2]
# Path to registered T1
t1_to_dif = os.path.join(outdir, "t1_brain.D_coord.nii.gz")
# First png: T1 registered in diffusion with nodif edges
t1_with_nodif_edges_png = os.path.join(qc_dir, "t1_with_nodif_edges.png")
plot_image(t1_to_dif,
edge_file=nodif_brain,
snap_file=t1_with_nodif_edges_png,
name="T1 in diffusion + edges of nodif",
cut_coords=nb_slices_in_z - 2)
# Second png: nodif with edges of T1 registered in diffusion
nodif_with_t1_edges_png = os.path.join(qc_dir, "nodif_with_t1_edges.png")
plot_image(nodif_brain,
edge_file=t1_to_dif,
snap_file=nodif_with_t1_edges_png,
name="nodif + edges of registered T1",
cut_coords=nb_slices_in_z - 2)
return dwi_wo_susceptibility, bval, bvec
def brainsuite_susceptibility_correction(outdir,
dwi,
bval,
bvec,
subject_id,
phase_enc_dir,
subjects_dir=None,
qc_dir=None,
bdp_nthread=4):
"""
Assuming the beginning of the preprocessing was done with Connectomist
up to Eddy current and motion correction, we now want to make susceptbility
distortion correction using Brainsuite.
Parameters
----------
outdir: str
Path to directory where to output.
dwi: str
Path to the preprocessed diffusion-weighted Nifti.
bval: str
Path to the bval file associated to the Nifti.
bvec: str
Path to the bvec file associated to the Nifti.
subject_id: str
Subject identifier used in Freesurfer.
phase_enc_dir: str
In plane phase encoding direction, "y", "y-", "x" or "x-".
subjects_dir: str, default None
If the Freesurfer $SUBJECTS_DIR environment variable is not set, or to
bypass it, pass the path.
qc_dir: str, default None
Path to directory where to output snapshots for QC. By default in
outdir.
bdp_nthread: int, default 4
Number of threads for bdp (see bdp.sh --thread flag)
"""
# Freesurfer 'subjects_dir' has to be passed or set as environment variable
subjects_dir = get_or_check_freesurfer_subjects_dir(subjects_dir)
# Check in plane phase encoding direction
# The sign of the phase encoding direction has no impact in this strategy
# e.g. for "+y" or "-y" use "y"
possible_phase_enc_dirs = {"y", "x"}
if phase_enc_dir not in possible_phase_enc_dirs:
raise ValueError("Bad argument 'phase_enc_dir': {}, should be in {}."
.format(phase_enc_dir, possible_phase_enc_dirs))
# Set and check path to T1 brain-only volume from Freesurfer (mgz format)
t1_brain_mgz = os.path.join(subjects_dir, subject_id, "mri/brain.mgz")
if not os.path.isfile(t1_brain_mgz):
raise Exception("Missing file: {}".format(t1_brain_mgz))
# Convert Freesurfer T1 to Nifti with reorientation to RAS (to be in the
# same orientation as the diffusion data)
t1_brain_RAS_nii = os.path.join(outdir, "t1_brain.nii.gz")
cmd = ["mri_convert", t1_brain_mgz, t1_brain_RAS_nii,
"--out_orientation", "RAS"]
run_freesurfer_cmd(cmd, subjects_dir=subjects_dir)
# Run bfc (bias correction: required by BrainSuite)
t1_bfc = os.path.join(outdir, "t1_brain.bfc.nii.gz")
cmd = ["bfc", "-i", t1_brain_RAS_nii, "-o", t1_bfc]
subprocess.check_call(cmd)
# Extract brain from the nodif volume with FSL bet2
nodif_brain = os.path.join(outdir, "nodif_brain.nii.gz")
bet2(dwi, nodif_brain, f=0.25, m=False)
# Run bdp.sh: registration + diffusion model
cmd = ["bdp.sh", t1_bfc, "--nii", dwi, "--bval", bval, "--bvec", bvec,
"--dwi-mask", nodif_brain, "--dir=%s" % phase_enc_dir,
"--threads=%i" % bdp_nthread]
subprocess.check_call(cmd)
# Path to files of interest, created by BrainSuite bdp.sh
dwi_wo_susceptibility = os.path.join(
outdir, "t1_brain.dwi.RAS.correct.nii.gz")
###############
# Quality check: create snapshots to visually assert the registration
# quality
if qc_dir is None:
qc_dir = outdir
# The snapshots won't contain all slices, half of them
nb_slices_in_z = nibabel.load(nodif_brain).get_shape()[2]
# Path to registered T1
t1_to_dif = os.path.join(outdir, "t1_brain.D_coord.nii.gz")
# First png: T1 registered in diffusion with nodif edges
t1_with_nodif_edges_png = os.path.join(qc_dir, "t1_with_nodif_edges.png")
plot_image(t1_to_dif,
edge_file=nodif_brain,
snap_file=t1_with_nodif_edges_png,
name="T1 in diffusion + edges of nodif",
cut_coords=nb_slices_in_z - 2)
# Second png: nodif with edges of T1 registered in diffusion
nodif_with_t1_edges_png = os.path.join(qc_dir, "nodif_with_t1_edges.png")
plot_image(nodif_brain,
edge_file=t1_to_dif,
snap_file=nodif_with_t1_edges_png,
name="nodif + edges of registered T1",
cut_coords=nb_slices_in_z - 2)
return dwi_wo_susceptibility, bval, bvec
def complete_preproc_wo_fieldmap(outdir,
dwi,
bval,
bvec,
phase_enc_dir,
subject_id,
subjects_dir=None,
invertX=True,
invertY=False,
invertZ=False,
delete_steps=False):
"""
Function that runs all preprocessing steps using Connectomist but
with BrainSuite for the correction of susceptibility distortions.
Parameters
----------
outdir: str
Path to directory where all the preprocessing will be done.
dwi: str
path to input diffusion-weighted Nifti data.
bval: str
Path to the Nifti's associated .bval file.
bvec: str
Ppath to Nifti's associated .bval file.
phase_enc_dir: str
In plane phase encoding direction, "y", "y-", "x" or "x-".
subject_id: str
Subject identifier used in Freesurfer.
subjects_dir: Str, default None
If the Freesurfer $SUBJECTS_DIR environment variable is not set, or to
bypass it, pass the path.
invertX: bool, default True
If True invert x-axis in diffusion model.
invertY: bool, default False
Same as invertX but for y-axis.
invertZ: bool, default False
Same as invertX but for z-axis.
delete_steps: bool
If True remove all intermediate files and directories at the end of
preprocessing, to keep only selected files:
- preprocessed Nifti + bval + bvec + outliers.py + nodif_brain*.nii.gz
Returns
-------
outdir: str,
Path to directory with the preprocessed files.
<unit>
<output name="preproc_dwi" type="File" />
<output name="preproc_bval" type="File" />
<output name="preproc_bvec" type="File" />
<input name="outdir" type="Directory" />
<input name="dwi" type="File" />
<input name="bval" type="File" />
<input name="bvec" type="File" />
<input name="phase_enc_dir" type="Str" />
<input name="subject_id" type="Str" />
<input name="subjects_dir" type="Str" />
<input name="invertX" type="Bool" />
<input name="invertY" type="Bool" />
<input name="invertZ" type="Bool" />
<input name="delete_steps" type="Bool" />
</unit>
"""
# Step 0 - Initialization
# Freesurfer 'subjects_dir' has to be passed or set as environment variable
subjects_dir = get_or_check_freesurfer_subjects_dir(subjects_dir)
# Raise an Exception if BrainsuiteCheck is not installed
check_brainsuite_installation()
# Create the preprocessing output directory if not existing
if not os.path.isdir(outdir):
os.makedirs(outdir)
# Step 1 - Import files to Connectomist and choose q-space model
raw_dwi_dir = os.path.join(outdir, "01-Import_and_qspace_model")
# The manufacturer option is unused (use brainsuite for susceptibility
# correction) but required
dwi_data_import_and_qspace_sampling(raw_dwi_dir,
dwi=dwi,
bval=bval,
bvec=bvec,
manufacturer="Siemens",
invertX=invertX,
invertY=invertY,
invertZ=invertZ,
subject_id=subject_id)
# Step 2 - Create a brain mask
rough_mask_dir = os.path.join(outdir, "02-Rough_mask")
dwi_rough_mask_extraction(rough_mask_dir, raw_dwi_dir)
# Step 3 - Detect and correct outlying diffusion slices
outliers_dir = os.path.join(outdir, "03-Outliers")
dwi_outlier_detection(outliers_dir, raw_dwi_dir, rough_mask_dir)
# Export outliers.py
path_outliers_py = os.path.join(outliers_dir, "outliers.py")
shutil.copy(path_outliers_py, outdir)
# Step 4 - Eddy current and motion correction
eddy_motion_dir = os.path.join(outdir, "04-Eddy_current_and_motion")
dwi_eddy_current_and_motion_correction(eddy_motion_dir, raw_dwi_dir,
rough_mask_dir, outliers_dir)
# Step 5 - Convert Connectomist result to Nifti with bval/bvec
dwi, bval, bvec = export_eddy_motion_results_to_nifti(eddy_motion_dir,
filename="dwi_ecc")
# Step 6 - Susceptibility correction using BrainSuite
brainsuite_dir = os.path.join(outdir, "05-Suceptibility_BrainSuite")
if not os.path.isdir(brainsuite_dir):
os.mkdir(brainsuite_dir)
dwi_wo_susceptibility, bval, bvec = \
brainsuite_susceptibility_correction(outdir=brainsuite_dir,
dwi=dwi,
bval=bval,
bvec=bvec,
phase_enc_dir=phase_enc_dir,
subject_id=subject_id,
subjects_dir=subjects_dir,
qc_dir=outdir)
# Step 7 - move corrected diffusion to outdir
dwi_preproc = os.path.join(outdir, "dwi.nii.gz")
bval_preproc = os.path.join(outdir, "dwi.bval")
bvec_preproc = os.path.join(outdir, "dwi.bvec")
shutil.copyfile(dwi_wo_susceptibility, dwi_preproc)
shutil.copyfile(bval, bval_preproc)
shutil.copyfile(bvec, bvec_preproc)
# Step 8 - Create a T2 brain mask of preprocessed DWI data
bet2_prefix = os.path.join(outdir, "nodif_brain")
nodif_brain = os.path.join(bet2_prefix + ".nii.gz")
nodif_brain_mask = os.path.join(bet2_prefix + "_mask.nii.gz")
bet2(dwi, bet2_prefix, f=0.25, m=True)
# Step 9 - clean intermediate directories if requested
if delete_steps:
intermediate_directories = [
raw_dwi_dir, rough_mask_dir, outliers_dir, eddy_motion_dir,
brainsuite_dir
]
for directory in intermediate_directories:
shutil.rmtree(directory)
return (outdir, dwi_preproc, bval_preproc, bvec_preproc, nodif_brain,
nodif_brain_mask)
def complete_preproc_wo_fieldmap(outdir,
dwi,
bval,
bvec,
phase_enc_dir,
subject_id,
subjects_dir=None,
invertX=True,
invertY=False,
invertZ=False,
delete_steps=False):
"""
Function that runs all preprocessing steps using Connectomist but
with BrainSuite for the correction of susceptibility distortions.
Parameters
----------
outdir: str
Path to directory where all the preprocessing will be done.
dwi: str
path to input diffusion-weighted Nifti data.
bval: str
Path to the Nifti's associated .bval file.
bvec: str
Ppath to Nifti's associated .bval file.
phase_enc_dir: str
In plane phase encoding direction, "y", "y-", "x" or "x-".
subject_id: str
Subject identifier used in Freesurfer.
subjects_dir: Str, default None
If the Freesurfer $SUBJECTS_DIR environment variable is not set, or to
bypass it, pass the path.
invertX: bool, default True
If True invert x-axis in diffusion model.
invertY: bool, default False
Same as invertX but for y-axis.
invertZ: bool, default False
Same as invertX but for z-axis.
delete_steps: bool
If True remove all intermediate files and directories at the end of
preprocessing, to keep only selected files:
- preprocessed Nifti + bval + bvec + outliers.py + nodif_brain*.nii.gz
Returns
-------
outdir: str,
Path to directory with the preprocessed files.
<unit>
<output name="preproc_dwi" type="File" />
<output name="preproc_bval" type="File" />
<output name="preproc_bvec" type="File" />
<input name="outdir" type="Directory" />
<input name="dwi" type="File" />
<input name="bval" type="File" />
<input name="bvec" type="File" />
<input name="phase_enc_dir" type="Str" />
<input name="subject_id" type="Str" />
<input name="subjects_dir" type="Str" />
<input name="invertX" type="Bool" />
<input name="invertY" type="Bool" />
<input name="invertZ" type="Bool" />
<input name="delete_steps" type="Bool" />
</unit>
"""
# Step 0 - Initialization
# Freesurfer 'subjects_dir' has to be passed or set as environment variable
subjects_dir = get_or_check_freesurfer_subjects_dir(subjects_dir)
# Raise an Exception if BrainsuiteCheck is not installed
check_brainsuite_installation()
# Create the preprocessing output directory if not existing
if not os.path.isdir(outdir):
os.makedirs(outdir)
# Step 1 - Import files to Connectomist and choose q-space model
raw_dwi_dir = os.path.join(outdir, "01-Import_and_qspace_model")
# The manufacturer option is unused (use brainsuite for susceptibility
# correction) but required
dwi_data_import_and_qspace_sampling(raw_dwi_dir,
dwi=dwi,
bval=bval,
bvec=bvec,
manufacturer="Siemens",
invertX=invertX,
invertY=invertY,
invertZ=invertZ,
subject_id=subject_id)
# Step 2 - Create a brain mask
rough_mask_dir = os.path.join(outdir, "02-Rough_mask")
dwi_rough_mask_extraction(rough_mask_dir, raw_dwi_dir)
# Step 3 - Detect and correct outlying diffusion slices
outliers_dir = os.path.join(outdir, "03-Outliers")
dwi_outlier_detection(outliers_dir, raw_dwi_dir, rough_mask_dir)
# Export outliers.py
path_outliers_py = os.path.join(outliers_dir, "outliers.py")
shutil.copy(path_outliers_py, outdir)
# Step 4 - Eddy current and motion correction
eddy_motion_dir = os.path.join(outdir, "04-Eddy_current_and_motion")
dwi_eddy_current_and_motion_correction(eddy_motion_dir,
raw_dwi_dir,
rough_mask_dir,
outliers_dir)
# Step 5 - Convert Connectomist result to Nifti with bval/bvec
dwi, bval, bvec = export_eddy_motion_results_to_nifti(eddy_motion_dir,
filename="dwi_ecc")
# Step 6 - Susceptibility correction using BrainSuite
brainsuite_dir = os.path.join(outdir, "05-Suceptibility_BrainSuite")
if not os.path.isdir(brainsuite_dir):
os.mkdir(brainsuite_dir)
dwi_wo_susceptibility, bval, bvec = \
brainsuite_susceptibility_correction(outdir=brainsuite_dir,
dwi=dwi,
bval=bval,
bvec=bvec,
phase_enc_dir=phase_enc_dir,
subject_id=subject_id,
subjects_dir=subjects_dir,
qc_dir=outdir)
# Step 7 - move corrected diffusion to outdir
dwi_preproc = os.path.join(outdir, "dwi.nii.gz")
bval_preproc = os.path.join(outdir, "dwi.bval")
bvec_preproc = os.path.join(outdir, "dwi.bvec")
shutil.copyfile(dwi_wo_susceptibility, dwi_preproc)
shutil.copyfile(bval, bval_preproc)
shutil.copyfile(bvec, bvec_preproc)
# Step 8 - Create a T2 brain mask of preprocessed DWI data
bet2_prefix = os.path.join(outdir, "nodif_brain")
nodif_brain = os.path.join(bet2_prefix + ".nii.gz")
nodif_brain_mask = os.path.join(bet2_prefix + "_mask.nii.gz")
bet2(dwi, bet2_prefix, f=0.25, m=True)
# Step 9 - clean intermediate directories if requested
if delete_steps:
intermediate_directories = [raw_dwi_dir,
rough_mask_dir,
outliers_dir,
eddy_motion_dir,
brainsuite_dir]
for directory in intermediate_directories:
shutil.rmtree(directory)
return (outdir, dwi_preproc, bval_preproc, bvec_preproc, nodif_brain,
nodif_brain_mask)
