Susceptibility weighted imaging - a problem-solving tool in differentiation of cerebellopontine angle schwannomas and meningiomas.

Background and purpose Vestibular schwannomas and meningiomas of the cerebellopontine angle can be differentiated by the presence of foci of blooming on susceptibility weighted imaging. Materials and methods In this retrospective study, magnetic resonance imaging with susceptibility weighted imaging sequence in addition to other routine sequences was done in 73 patients. All the cases were studied for the presence of foci of blooming within the tumor on susceptibility weighted imaging. Histopathological examination confirmed the diagnosis in all cases. Results There were 59 patients in the vestibular schwannoma group and 14 in the meningioma group. Susceptibility weighted imaging showed presence of blooming (due to microhemorrhages) in all the cases of cerebellopontine angle schwannomas. In the meningioma group, 13 cases showed no blooming within the lesion; one case showed blooming which was confirmed to be due to calcification on computed tomography study. For the detection of foci of blooming and predicting histopathologic diagnosis of schwannoma pre-operatively, susceptibility weighted imaging showed a sensitivity of 100%, specificity of 92%, positive predictive value of 98.3%, and negative predictive value of 100%. The Fisher exact test showed a statistically significant difference in the differentiation of vestibular schwannoma from meningioma on the basis of detection of blooming on susceptibility weighted imaging ( p < 0.0001). Conclusion Susceptibility weighted imaging is a problem-solving tool in making accurate pre-operative differentiation of vestibular schwannoma from meningioma.