Assess extent of resection and 4 vent outflow obstruction status post resection of medulloblastoma. There are interval postoperative findings related to suboccipital craniotomy for partial resection of a fourth ventricular tumor. The residual tumor measures up to approximately 35 mm in width. There is a channel for cerebrospinal fluid to communicate between the upper fourth ventricle and cerebral aqueduct, but the inferior fourth ventricle and outflow pathways remains largely effaced. There is interval insertion of a right transfrontal ventricular catheter that terminates in the right lateral ventricle. There is interval slight decrease in size of the third and lateral ventricles. There is hemorrhage layering within the occipital horns of the bilateral lateral and third ventricles. There are also globular structures with susceptibility effect and mildly high T2 signal in the lateral and third ventricles around the foramina of Monro. There is persistent diffuse periventricular white matter T2 hyperintensity. There are small areas of high T2 signal and restricted diffusion in the medial cerebellum along the surgical approach. There is fluid within the right maxillary sinus.
1. Interval partial resection of a fourth ventricular tumor and insertion of a right transfrontal ventricular shunt catheter. 2. Interval slight decrease in size of the third and lateral ventricles. 3. Globular structures with susceptibility effect in the lateral and third ventricles around the foramina of Monro may represent blood clots or displaced fragment of hemorrhagic tumor.