Petrous Apex and Anteriorly Located or Extended Cerebello-Pontine Angle Lesions: Radiological Assessment and the Management Modalities

Objective: The lesions occupying the petrous apex (PA) and/or the cerebello-pontine angle (CPA) anterior to the internal auditory canal contents are of great concern regarding the surgical choice of access. The decision of the best surgical approach also depends on the nature of the lesion. The thorough radiological assessment is imperative on the precise differential diagnosis leading to the best choice of treatment for this challenging region. Materials and Methods: A retrospective analysis was planned on thin section high resolution magnetic resonance images of the temporal bone region in the archieves of Radiology Department between April 2007 and October 2010. Results: Among the 1,860 patients, there were 10 primary PA entities (4 asymmetric bone marrow (ABM), 3 entrapped fluid, 1 cholesterol granuloma, 1 mucocele, 1 internal carotid artery (ICA) dissection) and 8 anteriorly extended or located CPA pathologies neighbouring PA (6 epidermoid tumors, 1 meningioma, 1 neurofibromatosis type-2 (NF 2) ). No primary PA cholesteatoma was noted. Of these 18 patients, 11 were female and 7 were male with the mean age of 35 years old, ranging between 18-55. Conclusion: The radiological evaluation is of utmost importance in the differential diagnosis in PA region due to the great difficulty of direct clinical evaluation. The precise diagnosis is imperative to choose whether to perform surgery or medical therapy. Besides the routine magnetic resonance imaging (MRI) assessment, complementary views including high resolution heavily 12 weighted sequences and diffusion weighted imaging (DWI) might be necessary. Bone algorythm computed tomography (CT) would be essential for the selection of treatment and the best approach to choose.