ABSTRACT
Patients with intracranial diseases frequently undergo multiple imaging studies during the course of their evaluation and treatment. Although these studies individually can provide important information, combining studies acquired using two different modalities into one integrated image set may enhance the clinician’s understanding of a patient’s disease. Because each modality has characteristic imaging capabilities, fusion of complementary images from different modalities can result in a synergistic image that shows the correspondence of features depicted by each imaging method. This can be seen in the registration of 201T1 single photon positron emission tomography (SPECT) and magnetic resonance (MR) images of the brain. Many functional modalities produce images showing radiopharmaceutical distribution, which demonstrate functional parameters of tissues but poorly display anatomy. On the other hand, conventional MR or computed tomography (CT) images demonstrate structural details well but offer little information about the physiology of these structures. By registering functional with structural images, the anatomical context of functional findings is enhanced. For example, areas of highgrade astrocytoma seen on 201T1 SPECT could be localized to a specific position within a complex lesion depicted on a MR image. This could be useful in assisting in both diagnosis and neurosurgical or radiotherapy planning.
