Evaluation of MRI findings in differentiating cerebellopontine angle tumors

Abstract

Background: Approximately 95-98% of cerebellopontine angle tumors are schwannoma and meningioma. However, it is challenging for radiologist to differentiate these tumors due to their similar clinical symptoms and MRI findings. Susceptibility weighted imaging have potential value to differentiate CPA meningioma from schwannoma. Purpose: The purpose of this study was to evaluate potential diagnostic value of SWI and conventional MRI findings in differentiating CPA schwannoma and meningioma. Materials and methods: In our retrospective study, pathologically confirmed 36 cases of CPA meningioma and schwannoma were included. 6 cases were excluded due to exclusion criteria. For all cases, MRI features were analyzed as following: volume of tumor, margin of tumor, Dural tail sign, involvement of IAC, tumor consistency, tumor enhancement. Results: Out of 30 patients with CPA meningioma and schwannoma, 24 (80%) were women, 6 (20%) were male and the mean age was 51.7+13.9. The Fisher exact test showed statistically signification difference in the differentiation of schwannoma from meningioma on the basis of detection of microhemorrhages on susceptibility weighted imaging (p<0.0001). The ICA involvement tended to be more common in schwannomas (16 of 19, 84%) than meningioma (p=0.012). MRI imaging features such as shape, size, location, Dural tail sign, peritumoral edema, 4th ventricle Compression were statistically not significant. Conclusion: MRI features were found to be helpful in differentiating CPA schwannoma from meningioma and predict pathological diagnoses of these tumors. SWI showed presence of blooming (due to microhemorrhages) in all the cases of cerebellopontine angle schwannomas. CA involvement, intra-tumoral cystic component were more specific for CPA schwannoma while Dural tail sign was more common in CPA meningioma.