The MRI was abnormal in seven of ten children with clinically proved neurofibromatosis reported from the Department of Radiology, the Oregon Health Sciences University, Portland, and the Departments of Neurology, Pediatrics and Radiology, University of Miami School of Medicine. Clinical diagnosis was based on six or more cafe-au-lait spots at least 1.5 cm in size. MRI was indicated because of mental retardation (5 patients), bilateral optic nerve tumors (1), shunt malfunction (1), learning disability (1), and possible brain tumor (2). The MRIs showed increased signal intensity on the T2-weighted images in the globus pallidus, brain stem, and cerebellum. The abnormalities most likely represented hamartomas. 
COMMENT. The MRI in this study was more revealing than the CT scan which was normal in all except one of the patients studied. The neurologic and developmental examinations showed no correlation with the MRI findings.