 There are post-therapy findings in the posterior fossa with cerebellar volume loss and distortion, confluent T2 hyperintensity in the cerebellar treatment zone and smaller areas of T2 hyperintensity in the brainstem that may include olivary degeneration, and persistent susceptibility effects and intrinsic T1 hyperintensity in the surgical cavity, but no evidence of residual nodular enhancement. There are also unchanged punctate foci of susceptibility effect in the right basal ganglia and left precentral gyrus, which may represent chronic microhemorrhages or cavernous malformations. There is no evidence of acute cerebral infarct. There is a posterior left ventricular catheter that terminates in the right lateral ventricle with persistent confluent high T2 signal in the brain parenchyma along the catheter track. There is unchanged T2 hyperintensity along the previous right ventriculostomy tract in the right frontal lobe. The lateral ventricles are perhaps slightly less collapsed.
Interval evolution of post-therapy findings in the posterior fossa without evidence of recurrent tumor.