CT angiography of the brain shows blood vessels and finds aneurysms and bleeding. Learn when it is advised, how it works and what the result means.
CT angiography of the brain is a fast contrast scan that shows the arteries of the brain. It is used to find aneurysms (weak bulging points in a vessel), the cause of bleeding around the brain, narrowing or blockage causing stroke, and abnormal vessel tangles. A sudden severe headache is an emergency and needs immediate care.
When Is It Done?
The classic emergency is a sudden, very severe headache, often described as the worst of life, sometimes with vomiting, stiff neck or loss of consciousness. A plain CT brain is done first to look for blood. If blood is seen, or the suspicion is high, CT angiography looks for the aneurysm. See CT brain scan.
ConditionWhat CT angiography may showSubarachnoid haemorrhage (bleeding around the brain)Ruptured aneurysm or other sourceUnruptured aneurysmSize, shape and neck of the bulgeStroke from a blocked vesselSite of blockageArteriovenous malformation (AVM)Abnormal tangle of vesselsNarrowing of brain arteriesAtherosclerosis or other diseaseOther Reasons for the Scan
- Stroke with sudden weakness or speech trouble, to find a clot and plan clot removal
- Follow-up of a known aneurysm or after treatment
- Family history of brain aneurysm in several relatives
- Unexplained bleeding in the brain
- Pulsating noise in the head in selected patients
How the Scan Works
Contrast is injected into a vein and the scanner is timed when brain arteries are brightest. The scan takes seconds. In an emergency, no preparation is needed. Planned scans need fasting for 4 to 6 hours and a creatinine report. See CT scan with contrast.
CT Angiography vs MR Angiography
CT is faster and better in emergencies and for finding bleeding. MR angiography avoids radiation and contrast in some cases and is used for screening and follow-up. Catheter angiography is the most detailed but invasive and used when treatment is planned. See MR angiography of brain and neck vessels and CT vs MR angiography.
A Practical Example
Kavita, 45, develops a thunderclap headache while lifting a bucket. CT brain shows blood around the brain. A CT angiography within minutes finds a small aneurysm in a brain artery. A neurosurgeon treats it with a coil that day, and she recovers well. Quick imaging allowed treatment before a second bleed.
Key Facts at a Glance
- Sudden severe headache is an emergency
- CT angiography finds aneurysms and vessel blockages
- The scan takes seconds
- Treatment may be by coiling, clipping or clot removal
After the Scan and Next Steps
Take the report and images to a neurosurgeon or neurologist at once if an aneurysm or bleeding is seen. Small unruptured aneurysms may be watched with regular scans, blood pressure control and quitting tobacco, while others are treated with coils or clips. Avoid heavy straining and uncontrolled blood pressure, and seek urgent care for a sudden severe headache.
Questions to Ask Your Doctor
- How large is the aneurysm and what is its rupture risk?
- Do I need treatment now or can it be watched?
- Should my relatives be screened?
- What symptoms mean I must come back immediately?
Common Mistakes to Avoid
- Waiting at home with the worst headache of your life.
- Smoking or uncontrolled blood pressure after the diagnosis.
- Skipping follow-up scans.
Booking, Timing and Report
Most CT scans can be booked on the same day, and the visit takes 20 to 40 minutes. Carry your prescription, old scans and a recent creatinine report if contrast is planned. Reports are usually ready within 24 hours, and images can be provided on a CD or digital link for your doctor.
Warning Signs and Prevention
Warning signs of a brain bleed include a sudden severe headache, neck stiffness, vomiting, double vision, drooping eyelid or loss of consciousness. To lower risk, control blood pressure, avoid tobacco, limit alcohol and take medicines regularly. Do not ignore a sudden unusual headache.
Frequently Asked Questions
What is an aneurysm?
A weak bulging point in an artery wall.
Can CT angiography find all aneurysms?
It finds most, especially larger ones.
Is it urgent?
In sudden severe headache, yes.
Do I need fasting?
Not in an emergency.
Is contrast safe?
Yes with kidney checks, and in emergencies benefits outweigh risks.
Can aneurysms run in families?
Yes, in some.
Do all aneurysms need surgery?
No. Small ones may be watched.
Can MR angiography be used instead?
Sometimes, for screening.
When is the report ready?
In emergencies, within minutes.
Book Your Test at Ganesh Diagnostic
Ganesh Diagnostic & Imaging Centre in Rohini, Delhi offers this test with trained radiology staff and clear reports. You can book an appointment online, check our branches across Delhi NCR, contact us for current rates, or explore all our services. Reports can be downloaded online through our patient portal, so you do not need to make a second trip just to collect them.
This article is for general information only. It does not replace advice from your doctor. Always follow your doctor's instructions for your test.
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