High-resolution diffusion tensor imaging using interleaved echo-planar imaging

Pathologic tissue damage frequently is associated with partial or complete loss of structural elements and is also reflected by alterations of the diffusivity of water molecules. Since single-shot echo-planar imaging (EPI) suffers from image degradation we seek to assess multi-shot EPI-based diffusion tensor imaging (DTI) for its potential to contribute to the diagnostic work-up of patients with neurologic disorders. Volunteer studies in subjects without any neurologic disorders served to document the reliability of this technique. Initial clinical applications in patients suffering from clinically definite relapsing-remitting MS were performed. Our measurements revealed high quality diffusion images of the entire brain with spatial resolution superior to that of conventional EPI scans. Critical regions, such as the brain stem or the cerebellum, were clearly visualized. The diffusion patterns observed were quite variable. It was found that certain diffusion characteristics are indicators of structural changes, and the underlying pathological phenomena may be related to pathological activity that has not been detected by other MRI techniques.