PROJECTING THE SULCAL PATTERN OF HUMAN BRAINS ONTO A 2D PLANE - A NEWAPPROACH USING POTENTIAL-THEORY AND MRI

A new method is introduced to project the sulcal pattern of the brain surface onto a 2D plane. Twin brains are compared against each other u sing the planar representation. We obtained T-1-weighted Flash-3D MRI volumes from 14 male twins (seven monozygotic, seven dizygotic) with 3 mm-thick coronal slices. The projection is based on potential theory: A virtual electrostatic field is calculated between the area of the se gmented brain and a surrounding spherical electrode. Field lines start ing from each border point of the segmented brain follow the gradient towards the sphere, leading to field line concentrations due to the un derlying sulci. The unwrapped sphere surface with the number of field lines per area unit is used as the 2D representation of the sulcal pat tern. The resulting brain projections show a distinctive pattern, and a visual assignment of the twin pairs from the unsorted set is possibl e because of a high similarity of the patterns between twin pairs. Glo bal correlation coefficients for each pair of maps yield significantly higher values for matching monozygotic twin pairs (mean = 20.2, range 12.3-25.6) than for unmatched pairs (mean = 13.0, range 1.1-28.5). As a conclusion, our method allows us to map the location and depth of t he sulci on a 2D plane. The resulting maps allow quantitative inter-in dividual comparisons on the entire brain or parts of the brain surface . (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.