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CT Angiography of Head Vessels With Intravenous Contrast

Published: August 9, 2026Updated: August 16, 2026

A CT scan uses intravenous contrast to create detailed images of blood vessels in the head, helping evaluate problems such as blockage or bleeding.

Quick summary

["This scan uses contrast and CT imaging to assess the blood vessels in your head."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
36830-8
Short code
CTA Head ves W contr IV
Synonyms
CTA Head ves W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct-angio
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

CT angiography of the head is an imaging test that shows the blood vessels in and around the brain. Intravenous contrast is injected to make the vessels easier to see on the pictures.

Why might I need this test?

Your clinician may order this test to investigate symptoms such as severe headache, weakness, speech trouble, vision changes, or seizures. It can also help evaluate known blood-vessel problems or plan treatment for a suspected aneurysm, clot, or blockage.

How is the test performed?

You lie on a CT table while a machine takes many X-ray images. Contrast is given through a vein in your arm, and the scan usually takes only a few minutes, although the visit may take longer.

How do I prepare for the test?

Follow your clinician's instructions and tell the imaging staff about kidney disease, prior contrast reactions, iodine allergy, or pregnancy. You may need to avoid food or drink before the scan, depending on local instructions and whether sedation is planned.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Head CT angiography

Frequently asked questions

Is this the same as a routine head CT?
Not exactly. This test focuses on the head's blood vessels and uses intravenous contrast, while a routine head CT is primarily used to view the brain and skull and may be performed without contrast.
Will the contrast make me feel unwell?
Some people notice a warm flush, a metallic taste, or nausea when contrast is injected. Rarely, contrast can cause an allergic-like reaction or affect kidney function, so tell the staff about any previous reaction or kidney disease.
Does this test require radiation?
Yes. CT imaging uses ionizing radiation, although a head CT angiogram generally involves a relatively brief exposure compared with more prolonged imaging studies.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy