Prototype of Sulci segmentation from  GM-CSF interface.
In the literature two possible approaches are described:
a) Having the Whole Brain (WM+GM) mask, segment Sulci using the GM-CSF interface.
b) Having the separate WM and GM mask, segment Sulci using the WM-GM interface.

MethodA is simpler to implement but there are much more difficult cases many sulci are too narrow to be reflected on the whole Brain Mask.

MethodB is considered more reliable, due to thicker layer of GM, but requires the WM-GM segmentation (not present in FireVoxel at the moment).

Here are the results of MethodA implemented in FireVoxel.  Sulci is represented as a color map where color corresponds to the length of the curved path from the "brain hull\envelop" to the particular point in sulcal space (measured in mm).

"Curved depth" map in 0.01 mm units.