听神经瘤英文PPT.ppt

Acoustic neuroma 听神经瘤 Introduction Acoustic neuroma originate from vestibular branch of aucoustic nerve Histologic feature: schwanoma, neuroma, Predilection: 30-50y Unilateral: majority Bilateral: Type II acoustic neuroma Vestibular-前庭 Pathology Predominate: internal auditory canal Extension to CPA Compression on brainstem and brain hydrops Anterior: trigeminal nerve, Medial: abducent nerve Inferior: IX, X, XI, XII CPA-小脑桥脑角 Work-up Audiometry Vestibular function: Neurologic exam Image study CT MRI Clinical presentations Hearing loss and tinnitus Progressive HL 90% 10% of patients complain of sudden HL. Unbalance Otalgia and compression due to depression of sensor fiber of facial nerve Involvement of trigeminal nerve Compression of cerebellum and brainstem: ataxia, nystagmus and intracranial hypo-pressure Otalgia-耳痛， ataxia-共济失调 ，nystagmus-眼球震颤 CT scan tumor in CPA, density is variform enlargement of internal auditory canal Enhanced CT scan, they are markedly enhanced. MR scan （2）The tumors were of hypo or iso-hypo intensity on T1 weighted images and hyper or iso-hyper intensity on T2 weighted images. （3）After enhanced the tumors were homogeneously or inhomogeneously or circularly enhanced MR scan (4）The margins of the tumors were smooth and well delineated. （5）The affected internal auditory canal usually became shorter in depth and larger in posterior anterior diameter. （6）MRI appearances of micro acoustic neuromas were that the affected Ⅶ,Ⅷ nerves were normal in size and the tumor revealed nodular or point enhancement at contrast enhanced (acoustic tumor) Same case Differential Diagnoses Meningiomas 1、The typical MR signal intensity characteristics of meningiomas are isointensity to slight hypointensity on T1WI,and isointensity to hypertensity on T2WI. 2、with enhanced MR or CT, they are markly enhanced ,and you may see the “Dural tail”. 3、tumor has wide basement, bony changes can be seen, but internal auditory canal w