Differentiation of cerebellopontine angle neuromas and meningiomas with MR imaging.

Postcontrast CT of the temporal bone is the neuroradiological study of choice for investigation of cerebellopontine angle (CPA) and internal auditory canal (IAC) lesions. Nonenhancing or small lesions may need CT combined with air or metrizamide cisternography for their detection. Magnetic resonance (MR) imaging has shown interesting capabilities as a noninvasive study for the visualization of the IAC, the neural bundle entering the canal, the brain stem, and cerebellum. In the present series of 24 cases, MR imaging detected the lesion in all 11 verified tumors. We feel that MR can replace invasive air and metrizamide cisternography in the diagnosis of CPA lesions and can help in the differentiation between acoustic neuromas and meningiomas.