A number of registration based automated methods have been designed for estimating progressive brain atrophy using MR imaging in previous longitudinal studies, such as voxel-based mor- phometry(VBM) 125] and boundary shift integral(BSI) [26l. In the current longitudinal study the scanner was up-traded into with a new gradient system with an 8channel receiving coil priorto the follow-up time point, which led to our decision touse SIENA, as it is less sensitive to confounds arising from the difference pattern in image intensity histograms of the brain images from two time points, which is common after scanner upgrades.
voxelwise brain edge points