Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions

Abstract

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions in the cerebellopontine angle (CPA). However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Part 1 describes the different enhancing extra-axial CPA masses primarily arising from the cerebellopontine cistern and its contents, including vestibular and non-vestibular schwannomas, meningioma, metastasis, aneurysm, tuberculosis and other miscellaneous meningeal lesions.

Role of Magnetic Resonance Imaging in Evaluation of Cerebellopontine Angle Schwannomas

“…This is especially true for any lesions in the cerebellopontine angle, where the sensitivity and specificity of MR imaging with its multidimensional imaging capabilities are far superior to that of CT. The high contrast resolution and multi planar capabilities of MR helps to delineate shape and margins, extent, mass effect, intensity at MR imaging, enhancement and adjacent bone reaction [6].…”

Cerebellopontine angle meningioma extending into internal auditory canal presenting with unilateral facial weakness and sensorineural hearing loss: Case presentation with review of literature

“…High-spatialresolution Magnetic Resonance Imaging (MRI) is the imaging of choice. Bonneville et al [13][14] reported categorisation of tumours of the cerebellopontine angle (CPA) on the basis of key neuroimaging features on contrast-enhanced MRI, which aid in more specifi c diagnosis and limit the differential diagnosis. Enhancing extra-axial lesions, such as in the case presented here, account for 80% to 95% of CPA tumours.…”

“…This case report describes in detail the clinical fi ndings, typical signal characteristics, more specifi c imaging features such as presence or absence Journal of Kathmandu Medical College Vol. of calcifi cation, a hemispheric or ice-cream-cone shape sign, adjacent hyperostosis, a 'dural tail', extension into one or more skull base neural foramina and enlargement of the IAC, which aids in a more specifi c diagnosis and skilled surgical management [13][14][15][16] .…”

Ekstraaksiyel Beyin Tumorleri

“…Vestibüler schwannomlar benign, yavaş büyü-yen schwann hücreleridir. Sıklıkla vestibüler sinirin inferior dalının gangliona yakın kesimi veya İAK'da glial ve schwann hücreleri geçiş zonunda görülür [85,86]. Her ne kadar daha ileri yaşta (4-8. dekad) görülse de nörofibroma-tozis tip 2'de daha genç hastalarda ve bilateral olarak izlenir [87].…”