الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The term cerebello-pontine angle was first introduced in 1902 by Henneberg and Koch when they reported two individuals with bilateral acoustic neuromas occurring in the location they described (in German) as the kleinhirnbruchen winkel (kleinhirn= cerebellum; bruchen = pons or bridge; and winkel = angle). The aim of the work is to evaluate the lesions that arise from this angle by using MRI sequences as T1 (without and with contrast), T2, FLAIR, diffusion weighted and spectroscopy. This study included 25 patients age ranged from 25 to 55 years with the mean SD 39+_9. The most age frequently involved was 25-35 years. Females are frequently involved by these lesions (19 patients) while males are less (6 patients). Among our patients, the most common presenting symptoms were hearing loss in 17 patients (68.0%),headache in10 patients (40.0%),tinnitus in 9 patients (36.0%),neuralgia in 5 patients (20.0%),vertigo in 2 patients (8.0%),hemifacial spasm in one patient (4.0%) and wasting muscle of mastication in one patient (4.0%). Lesions appear in MRI with different signals in T1 weighted image as :isointense in 20 patients (80.0%),hypointense in 4 patients (16.0%) and hyperintense in one patient (4.0%) ,while in T2 weighted image as:isointense in14 patients (56.0%),hyperintense in 10 patients (40.0%)and hypointense in one patient (4.0%).Using advanced techniques as DWI we can differentiate between lesions as epidermoid and arachinoid cystic lesions while MR spectroscopy differentiate between shcwannoma and metastesis in doubteful cases. Lesions appear with different signals after contrast administration as: homogenous enhancement in 16 patients (64.0%), heterogenous enhancement in Summary and conclusion 6 patients (24.0%), wall enhancement in one patient (4.0%) and no enhancement in 2 patients (8.0%). There are some associations finding in MRI helping in diagnosis as: extension into internal auditory canal in 8 patients (32.0%),dural tail in 5 patients (20.0%),dural base in 2 patients (8.0%) ,extension from skull base in one patient (4.0%) and no associations in 2 patients (8.0%). Out of the studied patients, final diagnosis by MRI revealed acoustic shawannoma in 12 patients (48.0%) which was the most common pathology, followed meningioma that were noted in 7 patients (28,0%), epidermoid cyst in one patient (4.0%) ,prominent AICA in one patient (4.0%) ,paragangilioma in one patient (4.0%),cystic neurofibroma in one patient (4.0%), neurofibromatosis type 2 in one patient (4.0%) and arachinoid cyst in one patient (4.0%). Many imaging modalities are used to differentiate the lesions arise from cerebellopontine angle including CT, MRI, PET CT and angiography. CT is the most available method for diagnosis of cerebellopontine angle lesions , but MRI is the golden method to differentiate the lesions by anatomical site of origin, shape, signal intensity and behavior after contrast media injection. Some cases needs complementary advanced MRI technique as diffusion weighted image and spectroscopy.