Maple syrup urine disease: findings on CT and MR scans of the brain in 10 infants.

Ten infants with classical maple syrup urine disease (MSUD) and two with variant MSUD had a total of 26 CT scans and 13 MR examinations of the brain during different stages of their disease. We found that inter- and intrapatient analyses of CT and MR findings at times ranging from 3 days to 7 months were typical enough to suggest the MSUD diagnosis. Imaging studies showed the natural course of the disease and, in a few cases, illustrated the effects of therapy. CT scans typically are negative during the first few days of life, then a marked, generalized, diffuse edema appears. In addition, a localized, more severe edema (the MSUD edema) is seen, which involves the deep cerebellar white matter, the dorsal part of the brainstem, the cerebral peduncles, and the dorsal limb of the internal capsule. Both the generalized and the MSUD edema subside during the second month of life, then may disappear totally or leave a well-defined, low-density zone around the lateral ventricles and small, low-attenuation lesions within the brainstem, respectively. With the disappearance of the edema, some loss of brain substance becomes obvious.