Volumetry and topography of the human brain by magnetic resonance imaging

Software, termed Morph, is described for the morphometric analysis of magne tic resonance images of the human brain. Algorithms for objective contrast border recognition, surface feature classification, and surface feature con tour unfolding are evaluated. Intraoperator and interoperator variabilities and errors were determined to be less than 2% over a group of operators (n = 6) for the known volume of a cerebral hemisphere obtained at autopsy. Vo lumetric errors were measured to be +/- 3% for simulated objects and less t han 1% for images of phantoms. Contours of brains of normal elderly subject s (n = 6) and patients with probable Alzheimer's disease (n = 6), segmented into sulcal and gyral features to determine gyrification indices, showed c oncordance with literature values. Flat maps or topograms were obtained of the convoluted cortex by unfolding the segmented contours. The areas of sur face features were readily obtained. The activation of the frontal eye fiel ds (FEF) defined by functional magnetic resonance imaging (fMRI) with an oc ulomotor control task was mapped onto a topogram of the precentral sulcus. This software provides accurate volumetric analysis with additional topogra phical tools for characterizing convoluted cortical features and for presen ting three-dimensional fMRI activation patterns as two-dimensional maps. (C ) 2001 John Wiley & Sons, Inc.