Labeled cortical mantle distance maps of the cingulate quantify differences between dementia of the Alzheimer type and healthy aging

Abstract

The cingulate gyri in 37 subjects with and without early dementia of the Alzheimer type (DAT) were studied by using MRI at 1.0 mm 3 isotropic resolution. Groups were segregated into young controls (n ‫؍‬ 10), age-matched normal controls (n ‫؍‬ 10), very mild DAT (n ‫؍‬ 8), and mild DAT (n ‫؍‬ 9). By using automated Bayesian segmentation of the cortex and gray matter͞white matter (GM͞WM) isosurface generation, tissue compartments were labeled into gray, white, and cerebrospinal fluid as a function of distance from the GM͞WM isosurface. Cortical mantle distance maps are generated profiling the GM volume and cortical mantle distribution as a function of distance from the cortical surface. Probabilistic tests based on generalizations of Wilcoxon-Mann-Whitney tests were applied to quantify cortical mantle distribution changes with normal and abnormal aging. We find no significant change between young controls and healthy aging as measured by the GM volume and cortical mantle distribution as a function of distance in both anterior and posterior regions of the cingulate. Significant progression of GM loss is seen in the very mild DAT and mild DAT groups in all areas of the cingulate. Posterior regions show both GM volume loss as well as significant cortical mantle distribution decrease with the onset of mild DAT. The ''shape of the cortical mantle'' as measured by the cortical mantle distance profiles manifests a pronounced increase in variability with mild DAT.

Dementia Update 2005

“…109 High resolution MRI can track regional AD involvement of the cerebral cortex, where gray matter loss in the cingulate gyrus and in posterior cortical areas appears to distinguish mild AD from nondemented aging. 110 Proton MR spectroscopy evaluates brain changes at the cellular level by measuring protoncontaining metabolites, including N-acetyl-aspartate (NAA), which is postulated to be a marker of neuronal integrity. A decrease in NAA in the posterior cingulate gyrus has been reported for mild-moderate AD.…”

A stochastic model for studying the laminar structure of cortex from MRI

“…The boundaries of the occipital lobe, for example, is defined by sulci, not by a boundary between gray and white matter. For these reasons, Van Essen and others have argued for the introduction of a second, local, 2-D coordinate system which is intrinsic to the cortical surface in the region of some particular gyrus [2]- [4].…”

Segmentation of arteries in MPRAGE images of the ventral medial prefrontal cortex

“…The means and standard deviations were obtained from sampling of voxels from the respective regions. The MR scan was then interpolated into 0.5 mm × 0.5 mm × 0.5 mm isotropic resolution using trilinear interpolation which allows for more accurate hand segmentation and smoother intensity histograms [3,10,37,[39][40][41].…”

“…Based on the computed gray/white thresholds, gray/ white surfaces were reconstructed using isosurface generation algorithms [10,40]. Labeled Cortical Depth Maps (LCDMs) were then generated from the surfaces [39,40]. These represent the density of gray matter tissue as a function of gray matter distance from the cortical surface and has been validated for the MPFC [10].…”