1. INTRODUCTION
Magnetic resonance imaging (MRI) is a highly successful diagnostic imaging modality, largely due to its ability to derive contrast from a number of physical parameters. The different types of MR images obtained from the different of excitation sequences, also called multispectral images, can provide different image intensity information for a given anatomical region and subject. As a tumor consists of different biologic tissues, one type of MRI cannot give complete information about abnormal tissues. Therefore, radiology experts always combine the multispectral MRI volumes of one patient to take a decision on the location, extension, prognosis and diagnosis of the tumors. That is why it is necessary to fuse multispectral MRI information to segment tumor regions.