I am trying to track the corticospinal tract, with a seed in the cerebral
peduncle. I was interested in seeing how adding different combinations of
exclusion and waypoint masks would effect the outcome, and am confused by
the waytotal results:
with no exclusion or waypoint mask: waytotal = 95000
exclusion mask at corpus collosum: waytotal = 94924
waypoint mask in internal capsule: waytotal = 64526
waypoint in internal capsule AND exclusion mask at corpus collosum: waytotal
same as above AND using FA to constrain tracking: waytotal = 61374
I am confused why the waytotal drops by so much when using both an exclusion
mask and waypoint mask. Shouldn't the difference between the waypoint mask
with and without the exclusion mask be the same as the difference when just
the exclusion mask was used compared to no additional masks (i.e.
95000-94924)? It also seemed strange that adding an additional constraint
(the FA constraint) resulted in a larger waytotal than without this
Any insight would be greatly appreciated.