 The cranium is large but the brain parenchyma is in general atrophic or underdeveloped. Both cerebral hemispheres are affected symmetrically and diffusely, though the frontal and temporal lobes appear to be slightly more affected. As such, the sylvian fissures are quite wide. The cerebellum and brainstem show relatively normal volume.The periventricular white matter of the cerebral hemispheres is symmetrically T2 hyperintense. This affects the deep white matter with sparing of the subcortical U-fibers. The subinsular white matter is questionably T2 hyperintense, as is the junction of the basal ganglia and thalami. The genu and splenium of the corpus callosum are T2 hyperintense, and furthermore, the posterior corpus callosum body and splenium are thinned. Striated T2 hyperintensity is seen in the pons, and there is patchy T2 hyperintensity at the dentate nuclei of the cerebellum.The degree of white matter myelination is difficult to assess on T2 weighted images due to the extensive signal abnormality as above. However, on T1 weighted images, the white matter signal pattern is commensurate with age at least in some areas, for example distally in the cerebral hemispheres. Symmetric bilateral expansion of the subarachnoid spaces is seen along the cerebral hemispheres. In addition, there are bilateral symmetric subdural collections which do not fully suppress on FLAIR images indicating the possibility of proteinaceous debris or old blood product. The ventricular system is mildly prominent, but not to the degree of the subarachnoid spaces.No restricted diffusion is seen. No evidence of acute intracranial hemorrhage is detected. No definite evidence of any migrational anomaly is seen. There is no evidence of an intracranial tumor or mass effect.
Multiple pathologic findings are seen, including symmetric bilateral signal abnormality affecting predominantly the deep cerebral white matter, the corpus callosum, the junction of the basal ganglia and thalami, the pons, and the cerebellum in the area of the dentate nuclei.Brain volume is significantly lower than normal suggesting either atrophy or underdevelopment. The cerebral hemispheres are affected diffusely, with perhaps mild preference for the frontal and temporal lobes. The sylvian fissures in particular are widened.Symmetric bilateral expansion of the subarachnoid spaces is seen. In addition, there are symmetric bilateral subdural collections suggesting prior subdural hemorrhage.The constellation of findings is most suggestive of an inborn error of metabolism or leukodystrophy. Several of the observed findings, including widened sylvian fissures and bilateral subdural collections, can be seen in glutaric aciduria type 1. However, other metabolic conditions must also be considered.