SPATIAL REGISTRATION AND NORMALIZATION OF IMAGES

This paper concerns the spatial and intensity transformations that may one image onto another. We present a general technique that facilitat es nonlinear spatial (stereotactic) normalization and image realignmen t. This technique minimizes the sum of squares between two images foll owing nonlinear spatial deformations and transformations of the voxel (intensity) values. The spatial and intensity transformations are obta ined simultaneously, and explicitly, using a least squares solution an d a series of linearising devices. The approach is completely noninter active (automatic), nonlinear, and noniterative. It can be applied in any number of dimensions. Various applications are considered, includi ng the realignment of functional magnetic resonance imaging (MRI) time -series, the linear (affine) and nonlinear spatial normalization of po sitron emission tomography (PET) and structural MRI images, the coregi stration of PET to structural MRI, and, implicitly, the conjoining of PET and MRI to obtain high resolution functional images. (C) 1996 Wile y Liss, Inc.