Segmentation methods (Fischl et al. 2002; Fischl et al. 2004) produced volumetric measures for 33 bilateral cerebral gray matter regions of interest (ROIs) that are not included in the neocortical surface, including hippocampus, amygdala, caudate, putamen, nucleus accumbens, thalamus, globus pallidus, cerebellar gray and white matter, ventricles (body and temporal horn of the lateral ventricle, third ventricle), cerebral cortex, white matter, and abnormally hypointense white matter regions. Measured white matter abnormalities reflect areas within the white matter that have abnormally low signal values (hypointensities) relative to normal white matter on T1-weighted images. These areas are analogous to the measure of hyperintensity derived from T2-weighted images and may reflect areas of inflammation, demyelination, or axonal loss.
