CT and MRI Findings of 4th Ventricular Tumors

ABSTRACT

PURPOSE: The purpose of our study is to evaluate characteristic features of 4th ventricular tumors in CT and MRI. MATERIALS AND METHODS: Pathologically proved 9 patients with 4th ventricular tumor were examined by CT and/or MRI. 4th ventricular tumors were epedymoma(4 cases), medulloblastoma(2 cases), choroid plexus papilIoma(2 cases), and oligodendroglioma(1 case). Included in our study were only those mass lesions that were located at surgery predominently within 4th ventricle with or without ventricular expansion. RESULTS: The origin of 4th ventricular tumor was the roof (epedymoma 3 cases, medulloblastoma 2 cases), the floor (epedymoma 1 case), and the undetermined(remaining 3 cases). On MRI, all tumors were hypointense exept ependymoma(3 cases) showing isointensity on T1WI. All tumors were hyperintense on PDWI and T2WI. On Gd-DTPA enhanced T1WI, strong enhancement was seen in all but epedymoma(1 case) which showed mild enhancement. On CT, as compared with MR images, various density on precontrast and postcontrast images were seen. Calcification was seen in choroid plexus papilloma(1 case) and oligodendroglioma(1 case). Hydrocephalus is seen in all cases exept ependymoma(2 cases) and oligodendroglioma(1 case). Hemorrhage within tumor was present only in epedymoma(2 cases). Cystic change or necrosis of tumor was seen in ependymomma(3 cases), choroid plexus papilloma(1 case), and oligodendroglioma(1 case). Peritumoral edema was seen in medulloblastoma(1 case). Extension through the foramen Luschka and the Magendie was seen in ependymoma(2 cases), choroid plexus papilloma(2 cases), and medulloblastoma(1 case). Seeding along the CSF pathway was seen only in ependymoma(2 cases). CONCLUSION: The results of our study may suggest that specific diagnosis of 4th ventricular tumor can be suggested preoperatively by analysing the origin in 4th ventricle, difference of CT density or MRI signal inten. sity, presence of extension or seeding through cerebrospinal fluid of the lesion.