Morphometry

Altered size and shape of brain structures can be observed in association with disease. These abnormalities can be detected using various structural MRI methods including voxel based morphometry and cortical thickness analysis of T1-weighted MRI scans.

There is increasing realisation that large multi-centre datasets can be a powerful means to reveal subtle abnormalities in brain structure associated with particular diseases. We therefore developed and validated methods for multi-site voxel based morphometry to allow scans from different labs and scanners to be analysed together.

In our investigations of cortical thickness, we have discovered that it is not just the cortical thickness value in a region that can reveal abnormality. We searched for differences in cortical thickness covariance – specifically, correlations of the cortical thicknesses of pairs of brain regions across individuals – in patients with Childhood Absence Epilepsy. We found significant differences compared to healthy controls, even though the absolute cortical thickness of any particular region was not significantly different between patients and controls. We hypothesise that we are detecting changes in the way brain regions grow together, influenced perhaps by genetic or other developmental factors, or possibly by epileptiform activity.