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CT Angiography, Region Not Clearly Specified — Without and With IV Contrast

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

A CT angiogram uses X-rays and intravenous contrast to examine blood vessels. Images may be taken before and after the contrast is given.

Quick summary

["This scan can help identify problems affecting the blood vessels, such as narrowing, blockage, aneurysm, or bleeding."]

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

Key facts at a glance

LOINC
36421-6
Short code
CTA UE ves WO+W contr IV
Synonyms
CTA UE ves WO+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, or CTA, is an X-ray-based imaging test that uses intravenous contrast to show blood vessels. The exact body region is not clear from the abbreviated test code, so the imaging center can confirm which vessels will be examined.

Why might I need this test?

A CTA may be ordered to evaluate symptoms such as sudden pain, weakness, numbness, a pulsating lump, or unexplained bleeding. It can also help assess blood-flow problems, arterial narrowing, blood clots, aneurysms, or complications after a procedure or injury.

How is the test performed?

You lie on a CT table while an X-ray scanner rotates around you. An IV line is used to administer contrast, and the scanner takes images before and after the contrast, depending on the study.

How do I prepare for the test?

Follow the imaging center's instructions about fasting, medications, and kidney function testing. Tell the care team about any contrast allergy, kidney disease, pregnancy possibility, or recent use of metformin, and do not have the IV placed until instructed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CT angiogram with and without IV contrast

Frequently asked questions

Does a CT angiogram use radiation?
Yes. It uses a dose of ionizing radiation, with or without intravenous contrast. The benefit of the scan generally outweighs the radiation exposure when it is medically appropriate.
Can I be allergic to the contrast used for a CTA?
Reactions are possible, particularly in people with a previous severe reaction to iodinated contrast. Tell the imaging team about any prior contrast reaction, kidney problems, or major allergies before the scan.
Will I need to stay at the imaging center afterward?
Most CT angiograms do not require an overnight stay. You may need brief observation after contrast, especially if you have kidney disease or a history of contrast reaction, and the center will explain the plan before the test.
  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