def reg_flirt(wsp, img, ref, initial_transform=None):
"""
Register low resolution ASL or calibration data to a high resolution
structural image using Flirt rigid-body registration
The brain extracted structural image is used as the reference image. If
this is not supplied, BET will be run on the whole head structural image.
:param reg_img: Data to register, e.g. PWI or calibration image. Normally would be brain extracted
:param struc_brain_img: Brain-extracted structural image
Optional keyword arguments:
:param inweight:
:param init: Initial transform matrix
:param schedule: FLIRT transform schedule file (default: xyztrans.sch")
:param dof: FLIRT degrees of freedom
:return Tuple of registered image, transform matrix
"""
wsp.log.write(" - Registering image: %s using FLIRT\n" % img.name)
# Step 1: 3D translation only
flirt_opts = {
"schedule":
os.path.join(os.environ["FSLDIR"], "etc", "flirtsch", "xyztrans.sch"),
"init":
initial_transform,
"inweight":
wsp.inweight,
"log":
wsp.fsllog,
}
step1_trans = fsl.flirt(img, ref, omat=fsl.LOAD, **flirt_opts)["omat"]
# Step 2: 6 DOF transformation with small search region
flirt_opts.update({
"schedule":
os.path.join(os.environ["FSLDIR"], "etc", "flirtsch",
wsp.ifnone("flirtsch", "simple3D.sch")),
"init":
step1_trans,
"dof":
wsp.ifnone("dof", 6),
})
flirt_result = fsl.flirt(img,
ref,
out=fsl.LOAD,
omat=fsl.LOAD,
**flirt_opts)
return flirt_result["out"], flirt_result["omat"]
def test_flirt():
with asrt.disabled(), run.dryrun(), mockFSLDIR(bin=('flirt', )) as fsldir:
flirt = op.join(fsldir, 'bin', 'flirt')
result = fw.flirt('src', 'ref', usesqform=True, anglerep='euler')
expected = (flirt + ' -in src -ref ref', ('-usesqform',
'-anglerep euler'))
assert checkResult(result.stdout[0], *expected)
def reg_struc2std(wsp, fnirt=False):
"""
Determine structural -> standard space registration
Optional workspace attributes
-----------------------------
- ``structural.struc`` : Structural image
- ``fslanat`` : Path to existing FSLANAT data
Updated workspace attributes
----------------------------
- ``reg.struc2std`` : Structural->MNI transformation matrix - either warp image or FLIRT matrix
- ``reg.std2struc`` : MNI->structural transformation - either warp image or FLIRT matrix
"""
init(wsp)
if wsp.reg.std2struc is not None:
return
if wsp.fslanat:
warp = os.path.join(wsp.fslanat, "T1_to_MNI_nonlin_coeff.nii.gz")
mat = os.path.join(wsp.fslanat, "T1_to_MNI_lin.mat")
if os.path.isfile(warp):
wsp.log.write(" - Using structural->std nonlinear transformation from FSL_ANAT\n")
wsp.reg.struc2std = Image(warp, loadData=False)
elif os.path.isfile(mat):
wsp.log.write(" - Using structural->std linear transformation from FSL_ANAT\n")
wsp.reg.struc2std = load_matrix(mat)
if wsp.reg.struc2std is None:
struc.init(wsp)
wsp.log.write(" - Registering structural image to standard space using FLIRT\n")
flirt_result = fsl.flirt(wsp.structural.brain, os.path.join(os.environ["FSLDIR"], "data/standard/MNI152_T1_2mm_brain"), omat=fsl.LOAD)
wsp.reg.struc2std = flirt_result["omat"]
if fnirt:
wsp.log.write(" - Registering structural image to standard space using FNIRT\n")
fnirt_result = fsl.fnirt(wsp.structural.brain, aff=wsp.reg.struc2std, config="T1_2_MNI152_2mm.cnf", cout=fsl.LOAD)
wsp.reg.struc2std = fnirt_result["cout"]
if isinstance(wsp.reg.struc2std, Image):
# Calculate the inverse warp using INVWARP
invwarp_result = fsl.invwarp(wsp.reg.struc2std, wsp.structural.struc, out=fsl.LOAD)
wsp.reg.std2struc = invwarp_result["out"]
else:
wsp.reg.std2struc = np.linalg.inv(wsp.reg.struc2std)
def reg_3d(cls, reg_data, ref_data, options, queue):
"""
Static function for performing 3D registration
"""
from fsl import wrappers as fsl
reg = qpdata_to_fslimage(reg_data)
ref = qpdata_to_fslimage(ref_data)
set_environ(options)
output_space = options.pop("output-space", "ref")
interp = _interp(options.pop("interp-order", 1))
twod = reg_data.grid.shape[2] == 1
logstream = six.StringIO()
flirt_output = fsl.flirt(reg,
ref,
interp=interp,
out=fsl.LOAD,
omat=fsl.LOAD,
twod=twod,
log={
"cmd": logstream,
"stdout": logstream,
"stderr": logstream
},
**options)
transform = FlirtTransform(ref_data.grid,
flirt_output["omat"],
name="flirt_xfm")
if output_space == "ref":
qpdata = fslimage_to_qpdata(flirt_output["out"], reg_data.name)
elif output_space == "reg":
qpdata = fslimage_to_qpdata(flirt_output["out"],
reg_data.name).resample(reg_data.grid,
suffix="")
qpdata.name = reg_data.name
elif output_space == "trans":
trans_affine = transform.voxel_to_world(reg_data.grid)
trans_grid = DataGrid(reg_data.grid.shape, trans_affine)
qpdata = NumpyData(reg_data.raw(),
grid=trans_grid,
name=reg_data.name)
return qpdata, transform, logstream.getvalue()
def epi_reg(wsp, epi_img, use_fmap=False, **kwargs):
"""
Do EPI registration
"""
struc.segment(wsp)
wmseg = wsp.structural.wm_seg
bbr_sch = os.path.join(os.environ["FSLDIR"], "etc/flirtsch/bbr.sch")
if wsp.asl2struc is None:
# Do pre-alignment in the same was as epi_reg
wsp.asl2struc = fsl.flirt(epi_img,
ref=wsp.structural.brain,
omat=fsl.LOAD,
dof=6,
log=wsp.fsllog)["omat"]
if not use_fmap:
wsp.log.write(" - Running BBR\n")
trans = fsl.flirt(epi_img,
ref=wsp.structural.struc,
dof=6,
cost="bbr",
wmseg=wmseg,
init=wsp.asl2struc,
omat=fsl.LOAD,
out=fsl.LOAD,
schedule=bbr_sch,
log=wsp.fsllog)["omat"]
out_img = fsl.applywarp(epi_img,
ref=wsp.structural.struc,
out=fsl.LOAD,
premat=trans,
interp="spline",
log=wsp.fsllog)["out"]
return {"out.nii.gz": out_img, "out": trans}
else:
dirmap = {
"x": (1, "x"),
"y": (2, "y"),
"z": (3, "z"),
"-x": (-1, "x-"),
"-y": (-2, "y-"),
"-z": (-3, "z-"),
"x-": (-1, "x-"),
"y-": (-2, "y-"),
"z-": (-3, "z-"),
}
pedir, fdir = dirmap.get(wsp.pedir, (None, None))
if pedir is None:
raise ValueError("Invalid phase encode direction specified: %s" %
wsp.pedir)
if wsp.nofmapreg:
wsp.fmap2struc = np.identity(4)
wsp.fmapmag_struc = wsp.fmapmag
else:
# Register fmap to structural image
wsp.log.write(" - Registering fieldmap to structural\n")
wsp.fmap2struc = fsl.flirt(wsp.fmapmagbrain,
ref=wsp.structural.brain,
dof=6,
omat=fsl.LOAD)["omat"]
flirt_result = fsl.flirt(wsp.fmapmag,
ref=wsp.structural.struc,
dof=6,
init=wsp.fmap2struc,
omat=fsl.LOAD,
out=fsl.LOAD,
nosearch=True)
wsp.fmap2struc = flirt_result["omat"]
wsp.fmapmag_struc = flirt_result["out"]
# Unmask the fieldmap (necessary to avoid edge effects)
wsp.fmap_mask = fsl.fslmaths(wsp.fmapmagbrain).abs().bin().run()
wsp.fmap_mask = fsl.fslmaths(wsp.fmap).abs().bin().mul(
wsp.fmap_mask).run()
# The direction here should take into account the initial affine (it needs to be the direction in the EPI)
wsp.fmap_unmasked = fsl.fugue(loadfmap=wsp.fmap,
mask=wsp.fmap_mask,
unmaskfmap=True,
savefmap=fsl.LOAD,
unwarpdir=fdir)["out"]
# The following is a NEW HACK to fix extrapolation when fieldmap is too small
wsp.fmap_struc_pad0 = fsl.applywarp(wsp.fmap_unmasked,
ref=wsp.structural.struc,
premat=wsp.fmap2struc,
out=fsl.LOAD)["out"]
wsp.fmap_struc_innermask = fsl.fslmaths(
wsp.fmap_struc_pad0).abs().bin().run()
wsp.fmap_struc_dilated = fsl.fugue(loadfmap=wsp.fmap_struc_pad0,
mask=wsp.fmap_struc_innermask,
unmaskfmap=True,
unwarpdir=fdir,
savefmap=fsl.LOAD)["savefmap"]
wsp.fmap_struc = wsp.fmap_struc_dilated
# Run bbr with fieldmap
wsp.log.write("Running BBR with fieldmap\n")
if not wsp.epi_reg_use_weighting:
refweight = None
wsp.reg.epi2struc = fsl.flirt(epi_img,
ref=wsp.structural.struc,
dof=6,
cost="bbr",
wmseg=wmseg,
init=wsp.reg.asl2struc,
omat=fsl.LOAD,
schedule=bbr_sch,
echospacing=wsp.echospacing,
pedir=pedir,
fieldmap=wsp.fmap_struc,
refweight=refweight)["omat"]
# Make equivalent warp fields
wsp.log.write(
"Making warp fields and applying registration to EPI series\n")
wsp.reg.struc2epi = np.linalg.inv(wsp.reg.epi2struc)
fsl.concatxfm(wsp.reg.struc2epi, wsp.fmap2struc, outmat=fsl.LOAD)
fsl.applywarp(wsp.fmap, ref=epi_img, premat=wsp.fmap2epi, out=fsl.LOAD)
wsp.fmap2epi_mask = fsl.fslmaths(wsp.fmap2epi).abs().bin().run()
# ${vout}_fieldmaprads2epi -abs -bin ${vout}_fieldmaprads2epi_mask
ret = fsl.fugue(loadfmap=wsp.fmap2epi,
mask=wsp.fmap2epi_mask,
saveshift=fsl.LOAD,
unmaskshift=True,
dwell=wsp.dwell,
unwarpdir=fdir)
print(ret)
wsp.fmap2epi_shift = ret["fieldmaprads2epi_shift"]
ret = fsl.convertwarp(wsp.structural.struc,
s=wsp.fmap2epi_shift,
postmat=wsp.epi2struc,
out=fsl.LOAD,
shiftdir=fdir,
relout=True)
print(ret)
warp = ret["out"]
ret = fsl.applywarp(epi_img,
ref=wsp.structural.struc,
out=fsl.LOAD,
warp1=warp,
interp="spline",
rel=True)
print(ret)
return ret["out"], warp
