19 years, Male, examination post tumor resection. History of ganglioglioma. Interval postsurgical changes of resection of recurrent tumor in the posterior fossa are seen. There is restricted diffusion involving the left cerebellar hemisphere along the posterior margin of the resection cavity related to blood products and/or cytotoxic edema. There is T1 shortening and susceptibility in the right paramedian region dorsal to the fourth ventricle related to blood products. There is no definite evidence of residual enhancing tumor. Expected postsurgical changes include small amount of pneumocephalus as well as extra-axial blood products in the posterior fossa. Air as well as blood products within the ventricular system are also noted. There is slight decrease in size of the ventricular system when compared to 1/12/2016.No midline shift or herniation. Again seen is a prominent CSF space/arachnoid cyst involving the right aspect of the pineal cistern with blood products indicative of communication with the ventricular system. Pronounced volume loss and areas of gliosis involving the right cerebellar hemisphere and right middle cerebellar peduncle related to prior treatment changes again noted. Major flow-voids are preserved.
Interval postsurgical changes related to resection of recurrent posterior fossa tumor as described above. No definite evidence of residual tumor is appreciated although blood products in the surgical bed limit evaluation for small residual lesions. Slight decrease in size of the ventricular system is noted.