def init_phdiff_wf(reportlets_dir, omp_nthreads, name='phdiff_wf'):
"""
Estimates the fieldmap using a phase-difference image and one or more
magnitude images corresponding to two or more :abbr:`GRE (Gradient Echo sequence)`
acquisitions. The `original code was taken from nipype
<https://github.com/nipy/nipype/blob/master/nipype/workflows/dmri/fsl/artifacts.py#L514>`_.
.. workflow ::
:graph2use: orig
:simple_form: yes
from fmriprep.workflows.fieldmap.phdiff import init_phdiff_wf
wf = init_phdiff_wf(reportlets_dir='.', omp_nthreads=1)
Outputs::
outputnode.fmap_ref - The average magnitude image, skull-stripped
outputnode.fmap_mask - The brain mask applied to the fieldmap
outputnode.fmap - The estimated fieldmap in Hz
"""
inputnode = pe.Node(
niu.IdentityInterface(fields=['magnitude', 'phasediff']),
name='inputnode')
outputnode = pe.Node(
niu.IdentityInterface(fields=['fmap', 'fmap_ref', 'fmap_mask']),
name='outputnode')
def _pick1st(inlist):
return inlist[0]
# Read phasediff echo times
meta = pe.Node(ReadSidecarJSON(),
name='meta',
mem_gb=0.01,
run_without_submitting=True)
dte = pe.Node(niu.Function(function=_delta_te), name='dte', mem_gb=0.01)
# Merge input magnitude images
magmrg = pe.Node(IntraModalMerge(), name='magmrg')
# de-gradient the fields ("bias/illumination artifact")
n4 = pe.Node(ants.N4BiasFieldCorrection(dimension=3, copy_header=True),
name='n4',
n_procs=omp_nthreads)
bet = pe.Node(BETRPT(generate_report=True, frac=0.6, mask=True),
name='bet')
ds_fmap_mask = pe.Node(DerivativesDataSink(base_directory=reportlets_dir,
suffix='fmap_mask'),
name='ds_fmap_mask',
mem_gb=0.01,
run_without_submitting=True)
# uses mask from bet; outputs a mask
# dilate = pe.Node(fsl.maths.MathsCommand(
# nan2zeros=True, args='-kernel sphere 5 -dilM'), name='MskDilate')
# phase diff -> radians
pha2rads = pe.Node(niu.Function(function=siemens2rads), name='pha2rads')
# FSL PRELUDE will perform phase-unwrapping
prelude = pe.Node(fsl.PRELUDE(), name='prelude')
denoise = pe.Node(fsl.SpatialFilter(operation='median',
kernel_shape='sphere',
kernel_size=3),
name='denoise')
demean = pe.Node(niu.Function(function=demean_image), name='demean')
cleanup_wf = cleanup_edge_pipeline(name="cleanup_wf")
compfmap = pe.Node(niu.Function(function=phdiff2fmap), name='compfmap')
# The phdiff2fmap interface is equivalent to:
# rad2rsec (using rads2radsec from nipype.workflows.dmri.fsl.utils)
# pre_fugue = pe.Node(fsl.FUGUE(save_fmap=True), name='ComputeFieldmapFUGUE')
# rsec2hz (divide by 2pi)
workflow = pe.Workflow(name=name)
workflow.connect([
(inputnode, meta, [('phasediff', 'in_file')]),
(inputnode, magmrg, [('magnitude', 'in_files')]),
(magmrg, n4, [('out_avg', 'input_image')]),
(n4, prelude, [('output_image', 'magnitude_file')]),
(n4, bet, [('output_image', 'in_file')]),
(bet, prelude, [('mask_file', 'mask_file')]),
(inputnode, pha2rads, [('phasediff', 'in_file')]),
(pha2rads, prelude, [('out', 'phase_file')]),
(meta, dte, [('out_dict', 'in_values')]),
(dte, compfmap, [('out', 'delta_te')]),
(prelude, denoise, [('unwrapped_phase_file', 'in_file')]),
(denoise, demean, [('out_file', 'in_file')]),
(demean, cleanup_wf, [('out', 'inputnode.in_file')]),
(bet, cleanup_wf, [('mask_file', 'inputnode.in_mask')]),
(cleanup_wf, compfmap, [('outputnode.out_file', 'in_file')]),
(compfmap, outputnode, [('out', 'fmap')]),
(bet, outputnode, [('mask_file', 'fmap_mask'),
('out_file', 'fmap_ref')]),
(inputnode, ds_fmap_mask, [('phasediff', 'source_file')]),
(bet, ds_fmap_mask, [('out_report', 'in_file')]),
])
return workflow
def init_fmap_wf(reportlets_dir, omp_nthreads, fmap_bspline, name='fmap_wf'):
"""
Fieldmap workflow - when we have a sequence that directly measures the fieldmap
we just need to mask it (using the corresponding magnitude image) to remove the
noise in the surrounding air region, and ensure that units are Hz.
.. workflow ::
:graph2use: orig
:simple_form: yes
from fmriprep.workflows.fieldmap.fmap import init_fmap_wf
wf = init_fmap_wf(reportlets_dir='.', omp_nthreads=6,
fmap_bspline=False)
"""
workflow = pe.Workflow(name=name)
inputnode = pe.Node(niu.IdentityInterface(
fields=['magnitude', 'fieldmap']), name='inputnode')
outputnode = pe.Node(niu.IdentityInterface(fields=['fmap', 'fmap_ref', 'fmap_mask']),
name='outputnode')
# Merge input magnitude images
magmrg = pe.Node(IntraModalMerge(), name='magmrg')
# Merge input fieldmap images
fmapmrg = pe.Node(IntraModalMerge(zero_based_avg=False, hmc=False),
name='fmapmrg')
# de-gradient the fields ("bias/illumination artifact")
n4_correct = pe.Node(ants.N4BiasFieldCorrection(dimension=3, copy_header=True),
name='n4_correct')
bet = pe.Node(BETRPT(generate_report=True, frac=0.6, mask=True),
name='bet')
ds_fmap_mask = pe.Node(
DerivativesDataSink(base_directory=reportlets_dir,
suffix='fmap_mask'), name='ds_fmap_mask')
workflow.connect([
(inputnode, magmrg, [('magnitude', 'in_files')]),
(inputnode, fmapmrg, [('fieldmap', 'in_files')]),
(magmrg, n4_correct, [('out_file', 'input_image')]),
(n4_correct, bet, [('output_image', 'in_file')]),
(bet, outputnode, [('mask_file', 'fmap_mask'),
('out_file', 'fmap_ref')]),
(inputnode, ds_fmap_mask, [('fieldmap', 'source_file')]),
(bet, ds_fmap_mask, [('out_report', 'in_file')]),
])
if fmap_bspline:
# despike_threshold=1.0, mask_erode=1),
fmapenh = pe.Node(FieldEnhance(
unwrap=False, despike=False, njobs=omp_nthreads),
name='fmapenh')
fmapenh.interface.num_threads = omp_nthreads
fmapenh.interface.estimated_memory_gb = 4
workflow.connect([
(bet, fmapenh, [('mask_file', 'in_mask'),
('out_file', 'in_magnitude')]),
(fmapmrg, fmapenh, [('out_file', 'in_file')]),
(fmapenh, outputnode, [('out_file', 'fmap')]),
])
else:
torads = pe.Node(niu.Function(output_names=['out_file', 'cutoff_hz'],
function=_torads), name='torads')
prelude = pe.Node(fsl.PRELUDE(), name='prelude')
tohz = pe.Node(niu.Function(function=_tohz), name='tohz')
denoise = pe.Node(fsl.SpatialFilter(operation='median', kernel_shape='sphere',
kernel_size=3), name='denoise')
demean = pe.Node(niu.Function(function=demean_image), name='demean')
cleanup_wf = cleanup_edge_pipeline(name='cleanup_wf')
applymsk = pe.Node(ApplyMask(), name='applymsk')
workflow.connect([
(bet, prelude, [('mask_file', 'mask_file'),
('out_file', 'magnitude_file')]),
(fmapmrg, torads, [('out_file', 'in_file')]),
(torads, tohz, [('cutoff_hz', 'cutoff_hz')]),
(torads, prelude, [('out_file', 'phase_file')]),
(prelude, tohz, [('unwrapped_phase_file', 'in_file')]),
(tohz, denoise, [('out', 'in_file')]),
(denoise, demean, [('out_file', 'in_file')]),
(demean, cleanup_wf, [('out', 'inputnode.in_file')]),
(bet, cleanup_wf, [('mask_file', 'inputnode.in_mask')]),
(cleanup_wf, applymsk, [('outputnode.out_file', 'in_file')]),
(bet, applymsk, [('mask_file', 'in_mask')]),
(applymsk, outputnode, [('out_file', 'fmap')]),
])
return workflow