What it is (overview)

An MRI Leg Angiogram with/without contrast (also called an MR angiography or MRA of the lower extremities) is an advanced imaging test that creates detailed pictures of the blood vessels in your legs. It uses a strong magnetic field and radio waves (not ionizing radiation like X-rays) to map blood flow through the arteries and, in some cases, the veins.

“With/without contrast” means your care team may take images without contrast first, and then may give an IV contrast agent (commonly a gadolinium-based dye) to make the blood vessels stand out more clearly. Some exams are completed without contrast if it’s not needed or if there are reasons to avoid it.

This test helps radiologists and vascular specialists look for problems such as blockages (narrowing), blood clots, poor circulation, and other vascular abnormalities. Results are typically described by whether vessels are open and flowing normally, or whether there is:

• Normal findings: Blood vessels are smooth, open, and blood flow appears adequate.

• Narrowing (stenosis): A vessel is partially blocked, which can reduce blood flow and contribute to leg pain with walking (claudication) or slow wound healing.

• Occlusion (complete blockage): Blood flow is severely limited or stopped in part of an artery, which may require urgent evaluation depending on symptoms.

• Clot or embolus: A blood clot may be seen in a vessel (the clinical urgency depends on location and symptoms).

• Abnormal vessel shape: Bulging (aneurysm), abnormal connections (arteriovenous malformation), inflammation, or injury to a vessel may be identified.

When & why it's usually done

Doctors often order an MRI leg angiogram when symptoms or exam findings suggest reduced blood flow or other vascular disease in the lower extremities. It may be used to diagnose a problem, determine how severe it is, or plan treatment (such as medication changes, angioplasty/stenting, or surgery).

Common reasons include:

Leg symptoms that may indicate poor circulation

• Cramping, aching, or heaviness in the calf, thigh, or buttock during walking that improves with rest (claudication)

• Persistent leg pain at rest, especially at night

• Coldness, numbness, tingling, or color changes in the foot/toes

• Non-healing sores, ulcers, or slow healing after minor injuries

• Weaker pulses in the feet or significant differences in blood pressure between legs

Concerns for a clot, blockage, or vessel injury

• Suspected blockages due to atherosclerosis (plaque buildup)

• Evaluation of suspected blood clots or abrupt changes in circulation

• Follow-up after trauma or suspected arterial injury

Risk factors that increase concern for vascular disease

• Smoking history

• Diabetes

• High blood pressure or high cholesterol

• Kidney disease (also affects contrast decisions)

• Known cardiovascular disease (coronary artery disease, carotid disease) or family history of early vascular disease

Why MRI/MRA may be chosen

An MRA can provide a detailed “road map” of leg blood vessels without X-ray radiation. It’s particularly helpful when your clinician needs high-resolution vessel images to locate narrowing, measure severity, or plan an intervention. “With or without” contrast allows flexibility—contrast can improve clarity, while non-contrast techniques may be used when contrast is not appropriate.

Common diseases related to it

• Peripheral artery disease (PAD) due to atherosclerosis
• Critical limb-threatening ischemia (severely reduced blood flow with rest pain, ulcers, or gangrene)
• Acute limb ischemia (sudden loss of blood flow from a clot or embolus)
• Deep vein thrombosis (DVT) or venous thrombosis (in select protocols when veins are evaluated)
• Aneurysm or pseudoaneurysm of leg arteries
• Arteriovenous malformation (AVM) or arteriovenous fistula
• Vasculitis (inflammation of blood vessels)
• Popliteal artery entrapment syndrome (compression of the artery near the knee)
• Thromboangiitis obliterans (Buerger disease)
• Post-surgical or post-procedure complications (stent or bypass graft narrowing/occlusion)

Health goals where it may help

• Identifying the cause of leg pain and walking limitation related to circulation
• Early detection and management of vascular disease to reduce the risk of ulcers, infection, or limb-threatening complications
• Evaluating suspected blockages or reduced blood flow before starting or adjusting treatment
• Assessing for blood clots or other vascular abnormalities when symptoms are concerning
• Planning procedures such as angioplasty, stenting, or bypass surgery by mapping leg blood vessels
• Monitoring known PAD or follow-up after vascular procedures to ensure vessels remain open
• Supporting broader cardiovascular risk reduction by clarifying the extent of atherosclerotic disease