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CT Angiography — With or Without IV Contrast

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

A CT angiogram uses X-rays and IV contrast to image blood vessels and assess narrowing, blockage, or abnormal connections.

Quick summary

["This scan provides detailed images of blood vessels to help evaluate circulation and identify vascular abnormalities."]

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

Key facts at a glance

LOINC
46309-1
Short code
CTA UE ves-R WO+W contr IV
Synonyms
CTA UE ves-R WO+W contr IV
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
20
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct-angio
CPT
85651
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 shows blood vessels in the scanned area. The order allows the scan to be performed with or without intravenous contrast, depending on clinical needs.

Why might I need this test?

A CTA may be ordered to evaluate symptoms such as pain, swelling, reduced blood flow, or a suspected blood vessel abnormality. It can help assess narrowing, blockage, aneurysms, or abnormal connections between vessels.

How is the test performed?

You lie on a CT table while an X-ray machine takes images from different angles. If contrast is used, it is usually given through a small IV in your arm, and the scan is completed quickly.

How do I prepare for the test?

Follow the imaging center’s instructions about eating, drinking, and medications. Tell the care team about contrast allergies, kidney disease, pregnancy, or prior contrast reactions before the scan.

Reference range

Adult males: 0-15 mm/hr; Females: 0-20 mm/hrN/A

Specimen: serum

No special preparation required. CRP may be affected by acute illness.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CTA findings may show blood vessel narrowing, blockage, aneurysms, or abnormal connections between vessels. The results are interpreted alongside symptoms, examination findings, and other tests. Your healthcare professional will explain what any abnormalities mean for your care.

Short name

CT angiogram

Frequently asked questions

Does a CTA always require IV contrast?
Not always. This order allows imaging with or without contrast, and the imaging team will confirm the approach before the scan.
Is a CT angiogram the same as a standard CT scan?
A CTA is a specialized CT scan focused on blood vessels. It may use IV contrast to make the vessels easier to see.
What should I do if I have reacted to contrast before?
Tell the imaging team before the appointment. They can review the prior reaction and determine what precautions or alternative imaging are appropriate.
  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