What is the clinical role of CT angiography in acute stroke evaluation?

• A. Measures brain perfusion only.
• B. Used only after MRI.
• C. Diagnoses hemorrhagic stroke by microbleeds.
• D. Identifies intracranial and extracranial vessel occlusions, assists in selecting candidates for thrombectomy and surgical planning.

Answer: (D)

CT angiography visualizes the brain’s arteries after contrast, so you can see exactly where a vessel is blocked in both the head and neck. This is why it’s so valuable in acute stroke: identifying a large-vessel occlusion directly determines whether a patient is a candidate for mechanical thrombectomy and guides the endovascular approach. CTA also maps the vascular anatomy, helping with planning and revealing issues like carotid stenosis or dissection that could affect treatment strategy. It’s not a perfusion study, so it doesn’t tell you how much brain tissue is at risk or already infarcted—that requires perfusion imaging. And while CTA provides critical vascular information quickly, MRI isn’t required for this assessment; in many centers CTA is part of the initial CT workup because it’s fast and widely available.