This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (E.N.T.), Subject name: ENT
[{'content': 'A patient is suspected to have Vestibular Shwanomma. The investigation of choice for its diagnosis is \nSelect and explain. \nA. Contrast enhanced CT scan, B. Gadolinium enhanced MR1, C. SPECT, D. PET scan', 'role': 'user'}, {'content': "Answer: B \nExplanation: (B) Gadolinium enhanced MRI # Neurological tests. Complete examination of cranial nerves, cerebellar functions, brainstem signs of pyramidal and sensory tracts should be done. Fundus is examined for blurring of disc margins or papilloedema.> Radiological tests, (a) Plain x-rays (transorbital, Stenver's, Towne's and submentovertical views) give positive findings in 80% of patients. However, small intracanalicular tumours are not detected.> CT scan. A tumour that projects even 0.5 cm into the posterior fossa can be detected by a CT scan. If combined with intrathecal air, even the intrameatal tumour can be detected.> CT scan has replaced earlier methods of pneumoencephalography and myodil meatography.> MRI with gadolinium contrast. It is superior to CT scan and is the gold standard for diagnosis of acoustic neuroma. Intracanalicular tumour, of even a few millimeters, can be easily diagnosed by this method.> Vertebral angiography. This is helpful to differentiate acoustic neuroma from other tumours of cerebellopontine angle when doubt exists.> Electric response audiometry. It is very useful in the diagnosis of retrocochlear lesions.> In the presence of VINth nerve tumour, a delay of >0.2 msec in wave V between two ears is significant.> CSF examination. Protein level is raised. Lumbar puncture is usually avoided.", 'role': 'assistant'}]