4D image warping for measurement of longitudinal brain changes

This paper presents a method for robustly measuring temporal morphological brain changes, by means of a 4D image warping mechanism. Longitudinal stability is achieved by considering all temporal MR images of an individual simultaneously in image warping, rather than by individually warping a 3D template to an individual, or by warping the images of one time-point to those of another time-point. Moreover, image features that are consistently recognized in all time-points guide the warping procedure, whereas spurious features that appear inconsistently at different time-points are eliminated. This deformation strategy significantly improves robustness in detecting anatomical correspondences, thereby producing smooth and accurate estimations of longitudinal changes. The experimental results show the significant improvement of 4D warping method over our previous 3D warping method in measuring subtle longitudinal changes of brain structures.