We present four pediatric cases examined by diffusion tensor MRI (DTI) to investigate microstructural abnormalities of brain related to their neurologic disability and motor weakness, following absence of any remarkable lesion on the motor pathway in conventional MRI. DTI is a relatively novel MR technique that enables investigation of the orientation and integrity of white matter fiber tracts of the brain in vivo. Case 1, 2 and 3 had suffered from cerebral palsy and case 4 had developed left hemiparesis
after a traumatic brain injury. Conventional brain MRI presented no specific abnormality in case 1 and 2, a focal encephalomalacia in the left anterior thalamus in case 3, and contusional hemorrhages in the left temporal and parietal lobes in case 4. But DTI disclosed microstructural abnormalities on descending motor pathway including the posterior limb of the internal capsule or the cerebral peduncle of the midbrain in all cases. (J Korean Acad Rehab Med 2003; 27: 446-450)
