This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Acoustic Neuroma, Subject name: ENT
Acoustic neuroma of 1 cm diameter, the investigation of choice: 
Select and explain. 
A. CT scan, B. MRI scan, C. Plain X-ray skull, D. Air encephalography
B: MRI scan
Answer: B: MRI scan 
Explanation: (b) MRI scan(Ref. Cummings, 6th ed., 2751)The gold standard investigation for the diagnosis of acoustic neuroma is gadolinium enhanced MRI. Even very small asymptomatic lesions can be observed by MRI.