Assess extent of resection and 4 vent outflow obstruction status post resection of medulloblastoma. There are interval postoperative findings related to suboccipital craniotomy for resection of a fourth ventricular tumor. There is globular mass with low T1 signal in the fourth ventricle that measures up to approximately 35 mm in width with susceptibility effect, but no discernible enhancement. There is also a component with relatively intermediate T1 signal along in the inferior aspect of the fourth ventricle. 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 patchy areas of high T2 signal and restricted diffusion in the medial cerebellar hemispheres along the surgical approach, which may represent There is fluid within the right maxillary sinus.
1. Interval gross total resection of a fourth ventricular tumor with blood clots in the ventricular system and what may represent a small amount of residual neoplasm along the inferior aspect of the fourth ventricle. Follow up MRI may be useful for distinguishing among these possibilities.2. Interval insertion of a right transfrontal ventricular shunt catheter with slight decrease in size of the third and lateral ventricles. 