Our research group develops methods to quantify brain changes based on MR images, providing tools to better understand normal brain development and the course of brain disorders such as Alzheimer’s Disease (AD). In particular, we have developed methods to extract the cerebral cortex from MR images of individual brains, using algorithms that include the delineation of the inner and outer boundaries of the cerebral cortex – See the figure below.

With this technique, we and other researchers can characterize the cerebral cortex in great detail, quantifying its local thickness, surface area, and the extent to which it folds (gyrification), both in the developing and ageing brain, and in patients with neurodevelopmental, psychiatric, or neurodegenerative disorders.

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Panel A shows how the cerebral cortex can be reconstructed from MR images using 3D surface meshes that delineate its inner and outer boundaries, although image voxels are large relative to the thickness of the cortex. Panel B shows a color-coding of the cerebral cortex, indicating its local thickness. The surface meshes also permit cortical surface area to be calculated and the cortex folding to be quantified. Panel D shows how these measurements provide invaluable tools when investigating the developing and ageing brain as well as a range of diseases and neurodevelopmental disorders. Panel E shows how accurate identification of the cortical surface allows specific brain regions to be identified (parcellation) on the otherwise convoluted brain surface. This ‘map’ of the brain territories provides important reference points when reporting the results of other types of MR acquisitions (e.g. diffusion-, perfusion-, or susceptibility-weighted) or molecular images recorded by positron emission tomography (PET). Panel F shows how high resolution MR images can be used in the attempt to identify specific cell layers of the cortex (adapted from Polimeni et al.)