Which statement about brain imaging in patients with acute dizziness is TRUE?
- In patients with BPPV, a brain MRI can help establish the diagnosis.
- In patients with posterior circulation stroke, the CT is diagnostic in >75% of cases.
- In patients with posterior circulation stroke, early MRI with diffusion-weighted images will establish the diagnosis in nearly all patients.
- In patients with vestibular migraine, neither CT nor MRI is indicated.
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Answer: D. In patients with spontaneous episodic vestibular syndrome, there is no specific test that distinguishes vestibular migraine from posterior circulation TIA, and decision-making must be individualized based on history, epidemiology, and context. In patients with triggered episodic vestibular syndrome who likely have BPPV, no diagnostic testing beyond physical examination is needed. Â CT scanning is notoriously unreliable for any acute ischemic stroke and is even worse in the posterior circulation. MRI with diffusion-weighted imaging can miss stroke if it is performed in the first 48 hours.
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