Role Of Mri In Assessment Of Cerebelloponting Angle Tumors:

Ahmed Abdellah Mahmoud

During the past 30 years, rapid and extensive progress hasmade in the diagnostic imaging of the brain. Most of the progresshas taken place in the development of new techniques in CT andMRI.MRI now the technique of choice for investigation most suspectedlesion of the brain especially the brain stem and posterior fossalesions.The absence of beam hardening artifacts, multiplanarcapability and greater soft tissue contrast make MR better than CT inevaluation of acoustic neuroma and similar pathologies of internalauditory canal and cerebellopontine angle.MRI shows a higher level of soft tissue contrast even withoutthe use of contrast material and can show either. the normal 7th and8th nerves or. acoustic tumours. Enhanced MRI, in fact, shows upsmall volumetric modifications of the facial acoustic bundle, so that.small tumors, less than 1em, that would be undetected by a CT scan,can be clearly identified.Yet, MRI is a relatively expensive imaging modality.Therefore new MRI techniques with a high sensitivity and a lowercost are being studied .•• _ •• ”” 106,•••-•-------- ••Summary and Conclusion•• iiiiiiiiiiiil!iliii!!iiiiiiiiiii!iliii!!!iliii!!!iliii!!i!!!!!!!!!!!!!I!iiiiiiiiiiiiiiiii!iliii!!E!!!!i!!!!!!!i!!!!!!!!!!!!!!!!!i!!!!! •••• Lesions of the cerebellopontine angle are divided into thesenative to the angle (vestibular schawannoma, meningioma,•epidermoid, arachnoid cyst, metastases, lipoma etc) and thoseextending to the angle from adjacent structure (glioma,ependymomas, choroid plexus papilomas, vascular malformation)The site of origin is the main factor in making a preoperativediagnosis for a lesion of CPA. In addition, it is essential to analyzesignal intensity at magnetic resonance (MR) imaging, enhancement,.shape and margins, extent, mass effect, and adjacent bone reaction.