Neuroradiology
What the exam tests
Neuroradiology covers acute stroke, intracranial hemorrhage, tumors, infection, spine disease, and head/neck imaging. Expect CT/CTA/CT perfusion, MRI stroke protocols, and hemorrhage patterns.
Core rules
- Noncontrast head CT is first-line in acute stroke to exclude hemorrhage; early CT may be normal in ischemia.
- Hyperdense MCA sign suggests thrombus; CTA identifies large-vessel occlusion.
- ASPECTS quantifies early ischemic change; lower scores predict worse outcome.
- MRI diffusion-weighted imaging is highly sensitive for acute infarction; ADC maps confirm restricted diffusion.
Worked example
A 65-year-old with sudden aphasia has a noncontrast CT without hemorrhage, a hyperdense left MCA, and CTA showing left M1 occlusion. Reasoning: this is an acute large-vessel occlusion. The patient should be evaluated urgently for mechanical thrombectomy within the appropriate time window, after excluding hemorrhage and assessing eligibility. ASPECTS and perfusion imaging help select patients.
Traps
Missing subtle subarachnoid hemorrhage; calling a hyperdense vessel calcification; ignoring that early CT can be normal; and failing to assess the time window.
Key points
- Noncontrast CT excludes hemorrhage before thrombolysis.
- Hyperdense MCA suggests thrombus.
- CTA identifies large-vessel occlusion for thrombectomy.
- DWI/ADC confirms acute infarct.
- ASPECTS estimates early ischemic burden.