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CT Angiography, Lower Extremity, Venous — With Intravenous Contrast

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

Uses CT imaging and intravenous contrast to examine the veins of the lower leg, usually to evaluate for blood clots or venous blockage.

Quick summary

["This imaging test helps identify blood clots and other problems affecting the veins of the lower leg."]

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

Key facts at a glance

LOINC
36831-6
Short code
CTA LE ves W contr IV
Synonyms
CTA LE 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?

Lower-extremity venous CT angiography is an imaging test that uses computed tomography and intravenous contrast to show the veins in the leg. It can help locate blood clots, identify blocked or narrowed veins, and assess blood flow around a clot.

Why might I need this test?

This test may be ordered when a blood clot is suspected, particularly after symptoms such as leg swelling, pain, warmth, or redness. It may also be used to evaluate venous obstruction, guide treatment, or assess the location and extent of a known clot.

How is the test performed?

An intravenous line is placed, usually in the arm, and contrast medicine is injected. The scanner then takes rapid X-ray images of the lower legs, and a radiologist reviews them for clots or other abnormalities.

How do I prepare for the test?

Follow the imaging center's instructions about eating, drinking, and medications. Tell the care team about prior contrast reactions, severe allergies, kidney disease, pregnancy, or possible pregnancy, because these factors may affect the test or its safety.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

The test may reveal a blood clot, blockage, or narrowing of a lower-extremity vein. Findings can also show collateral veins or other changes related to impaired venous circulation. Results should be interpreted by your clinician in combination with your symptoms, examination, and other tests.

Short name

Lower-extremity venous CT angiography

Frequently asked questions

Does this test use radiation?
Yes. CT angiography uses a small dose of ionizing radiation along with intravenous contrast to create detailed images of the veins.
Is the test painful?
The scan itself is generally painless, but the intravenous injection may cause a brief warm or flushing sensation. Some people may be sore or bruised at the injection site afterward.
How soon will the results be available?
A radiologist typically reviews the images and sends a report to your ordering clinician. The timing of your results and any next steps depends on how urgently the test was ordered.
  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