Magnetic Resonance Angiography (MRA), Knee/Lower Extremity — With or Without IV Contrast
An MRI-based imaging test that evaluates blood vessels in the knee or lower limb, sometimes using intravenous contrast.
["This test helps assess the blood vessels of the knee or lower limb for narrowing, blockage, or other vascular abnormalities."]
Key facts at a glance
- LOINC
- 38837-1
- Short code
- MRA Knee ves-L WO+W contr IV
- Synonyms
- MRA Knee ves-L 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
- mr-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?
Magnetic resonance angiography, or MRA, is an imaging test that uses a strong magnetic field and radio waves to create detailed pictures of blood vessels. Depending on the order, it may be performed with or without intravenous contrast, a special dye that makes vessels easier to see.
Why might I need this test?
MRA may be used to evaluate suspected narrowing or blockage of arteries, aneurysms, blood clots, or problems affecting venous blood flow. It may also help assess the location and severity of a vascular problem or plan treatment.
How is the test performed?
You will usually lie on a movable table inside an MRI scanner while the machine creates images of the specified blood vessels. If intravenous contrast is used, it is given through a vein in your arm, and the scan generally lasts longer than a noncontrast examination.
How do I prepare for the test?
Tell your care team about metal implants, pacemaker devices, prior contrast reactions, kidney disease, and any possibility of pregnancy. Remove jewelry and other metal objects when instructed, and follow the facility's instructions about eating, drinking, and taking medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal findings may indicate narrowing, obstruction, an aneurysm, or a blood clot involving the arteries or veins of the imaged area. The significance depends on the symptoms, the vessels examined, and the degree of the abnormality. A radiologist will interpret the images in the context of your examination and other tests.
Short name
MRA of the knee/lower extremity
Frequently asked questions
Does MRA use radiation?
Is intravenous contrast always required?
What should I do if I am pregnant or may be pregnant?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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