Release Name: 1.3
Notes:
This release adds three new files to MCALT: 1) a 0.5mm T1-weighted
template image; 2) a mask of voxels inside the cranial vault, i.e.
the TIV; 3) a segmentation mask designed to remove misclassified
adjacent regions of gray-matter-isointense dura from medial
temporal lobe (MTL) segmentations.
* ./MCALT_T1_05mm.nii
A higher-resolution (0.5mm) version of MCALT space. This is not the
version on which all MCALT atlases were drawn and defined
(MCALT_T1.nii). We created this version later, intended primarily
for visualizations. It is possible to use this 0.5mm version for
atlas propagation, but this has not been rigorously tested. To
create this image, the same 202 (~1mm T1-weighted) MRI as in the
standard MCALT template were coregistered using
buildTemplateParallel.sh from the ANTs package, using a copy of
MCALT_T1.nii up-sampled to 0.5mm as a rigid reference target. A
single warp (masked to prioritize matching brain voxels) was then
calculated between the generated 0.5mm template image and the
standard (1.5mm) MCALT_T1.nii. This final warp improved the
voxel-wise correspondence between the template versions, thus
making it possible to consider this new image to be in the same
voxel "space" as MCALT, rather than a new and incompatible template
space. All 202 scans were warped via the transforms generated by
buildTemplateParallel concatenated with the final warp across
templates, then averaged, to create the final MCALT_T1_05mm.nii
* ./MCALT_TIVmask.nii
A mask of MCALT voxels that exist inside the cranial vault, i.e.
the total intracranial volume.
* ./atlas/MCALT_MTL_nogo.nii
MCALT_MTL_nogo is a mask designed primarily to remove misclassified
adjacent regions of gray-matter-isointense dura from medial
temporal lobe (MTL) segmentations. It contains non-brain voxels,
proximal to the medial temporal regions, that SPM12 segmentations
can sometimes misclassify as brain despite their being labelled as
non-brain in our MCALT_tpm. For better segmentation accuracy, we
recommend that this mask be applied after segmentation to set any
contained voxels as non-GM and non-WM. We typically apply this mask
to improve segmentation results in native space. It may also be
reasonable to apply this mask to segmentations in template space,
but we have not tested it for that use.
Changes:
* Add MCALT_T1_05mm.nii
* Add MCALT_TIVmask.nii
* Add atlas/MCALT_MTL_nogo.nii
|