Cerebral cortex: a topographic segmentation method using magnetic resonance imaging

Remarkable developments in magnetic resonance imaging (MRI) technology prov ide a broad range of potential applications to explore in vivo morphologica l characteristics of the human cerebral cortex. MR-based parcellation metho ds of the cerebral cortex may clarify the structural anomalies in specific brain subregions that reflect underlying neuropathological processes in bra in illnesses. The present study describes detailed,guidelines for the parce llation of the cerebral cortex into 41 subregions. Our method conserves the topographic uniqueness of individual brains and is based on our ability to visualize the three orthogonal planes, the triangulated gray matter isosur face and the three-dimensional (3D) rendered brain simultaneously. Based up on topographic landmarks of individual sulci, every subregion was manually segmented on a set of serial coronal or transaxial slices consecutively. Th e reliability study indicated that the cerebral cortex could be parcelled r eliably; intraclass correlation coefficients for each subregion ranged from 0.60 to 0.99. The validity of the method is supported by the fact that gyr al subdivisions are similar to regions delineated in functional imaging stu dies conducted in our center. Ultimately, this method will permit us to det ect subtle morphometric impairments or to find abnormal patterns of functio nal activation in circumscribed cortical subregions. The description of a t horough map of regional structural and functional cortical abnormalities wi ll provide further insight into the role that different subregions play in the pathophysiology of brain illnesses. (C) 2000 Elsevier Science Ireland L td. All rights reserved.