 Redemonstrated is decreased volume of the left cerebral hemisphere and asymmetry of the basal ganglia, thalamus and cerebral peduncles. Again noted is abnormal signal around the ventricles. The corpus callosum is fully formed, although appears somewhat blunted on the anterior most genu, with the midline falx present. Asymmetric prominence of the right lateral ventricle, but is slightly decreased in size along with the third ventricle. There is interval decrease in the size of the subarachnoid spaces. Evaluation of the posterior fossa again demonstrates fourth ventricular enlargement with communication of the the fourth ventricle with a posterior fossa space, hypoplasia of the vermis, mild superior displacement of the fourth ventricle and vermis, and mild enlargement of the posterior fossa. There is no mass effect. There are no areas of abnormal signal. There is no diffusion abnormality. No extra-axial fluid collection is identified. Normal flow-voids are demonstrated in the major intracranial vascular structures. Incidentally noted is a prominent node of Rouviere on the right measuring 12 mm, which is likely reactive.The inadvertently performed CSF flow sequence demonstrates biphasic flow ventral and dorsal to the cervicomedullary junction as well as flow in the aqueduct and 4th ventricle.
1. Unchanged constellation of posterior fossa findings suggestive of a Dandy-Walker variant/spectrum.2. Generalized decreased volume of the left cerebral hemisphere in comparison to the contralateral side including similar asymmetry of the basal ganglia, thalami, and left cerebral peduncle. 3. Abnormal signal findings around the ventricles, favoring delayed myelination and/or gliosis, and less likely heterotopia.4. Prominence of the right lateral ventricle and third ventricle is slightly decreased in extent as well as the previously noted prominence of the subarachnoid spaces, likely relating to resolving benign external enlargement of subarachnoid spaces which usually resolves by two years of age. 