IMAGING FEATURES OF VARIOUS CEREBELLO-PONTINE ANGLE LESIONS

Abstract

Introduction:

Cerebellopontine angle (CPA) tumours usually are classified into intra-axial, extra-axial, skull base tumours. Although vestibular schwannomas and meningiomas constitute the vast majority of the cerebellopontine angle (CPA) lesions, a large variety of unusual lesions can also be encountered in the CPA.

In the present study, the CT and MRI imaging features of various cerebellopontine angle tumours are evaluated.

Material and Methods:

All patients with clinical suspicion of cerebellopontine (CP) angle tumours are subjected to scan on the 1.5T MR imaging system. Special sequences such as DWI, MR spectroscopy were performed.

Results:

Acoustic schwannomas, which are also known as Vestibular schwannomas, and meningiomas are the two most frequent lesions and account for approximately 85%-90% of all CPA tumours. The other 10%-15% includes a large variety of lesions that will be recognised more frequently because of the remarkable sensitivity and accuracy of magnetic resonance imaging in the evaluation of a CPA syndrome. Computerised tomography (CT) and magnetic resonance imaging (MRI) are the primary modalities for diagnosis of cerebellopontine lesions. MRI is considered superior in differentiating the different types of Cerebellopontine angle (CPA) masses. Knowledge of typical signal characteristics and more specific features such as a hemispheric or ice-cream cone shape, a dural tail, adjacent hyperostosis, extension into one or more skull base foramina, and enlargement of the internal auditory canal (IAC) helps in limiting the differentials considered. Recent advanced MRI techniques that include diffusion-weighted imaging (DWI), MR spectroscopy, and MR perfusion can help provide a more specific diagnosis.

Conclusion:

MRI is the most sensitive noninvasive modality to characterise CP angle tumours. MRI identifies the exact location and extension of the lesions based on their signal characteristics and contrast enhancement pattern.