A GENERAL TECHNIQUE FOR INTERSTUDY REGISTRATION OF MULTIFUNCTION AND MULTIMODALITY IMAGES

A technique that can register anatomic / structural brain images (e.g,, MRI) with various functional images (e.g., PET-FDG and PET-FDOPA) of the same subject has been developed. The procedure of this technique includes the following steps: 1) segmentation of MRI brain images into gray matter (GM), white matter (WM), cerebral spinal fluid (CSF), and, muscle (MS) components, 2) assignment of appropriate radiotracer concentrations to various components depending on the kind of functional image that is being registered, 3) generation of simulated functional images to have a spatial resolution that is comparable to that of the measured ones, 4) alignment of the measured functional images to the simulated ones that are based on MRI images. A self-organization clustering method is used to segment the MRI images. The image alignment is based on the criterion of least squares of the pixel-by-pixel differences between the two sets of images that are being matched and on the Powell's algorithm for minimization. The technique was applied successfully for registering the MRI, PET-FDG, and PET-FDOPA images. This technique offers a general solution to the registration of structural images to functional images and to the registration of different functional images of markedly different distributions.