index name abbr mapping 0 "Background" BG 0 1 "Cerebrospinal Fluid" CSF 3 2 "Cortical Grey Matter" CGM 9 3 "Subcortical Grey Matter" SCGM 10 4 "White Matter" WM 2 5 "Brainstem" BS 11 6 "Cerebellum" CBM 12
