MR angiography (MRA) is a non-invasive imaging method that uses magnetic resonance technology to visualize blood vessels. It provides detailed vascular mapping without the use of ionizing radiation.
Contrast-enhanced or time-of-flight techniques are commonly applied, depending on the vascular region of interest. MRA is widely used for cerebral, carotid, renal, and peripheral artery evaluation.
Compared to conventional angiography, MRA reduces procedural risks and avoids catheter insertion. It is especially valuable in patients with contraindications to iodinated contrast media.
Clinical indications include suspected vascular stenosis, aneurysms, malformations, or thrombotic disease. MR angiography ensures accurate diagnosis and supports precise treatment planning.
| Imaging Method | MR Angiography (MRA) |
| Definition | An imaging method that provides detailed visualization of blood vessels using magnetic resonance imaging (MR) technology. Vessels are visualized with radio waves and a strong magnetic field without the use of X-rays. |
| Indications | Examination of various vessels in the body such as cerebral vessels (Circle of Willis, aneurysm and vascular occlusions), carotid arteries, coronary arteries, peripheral vessels, and renal arteries. |
| Advantages | Shows vessels in detail without an invasive procedure; contains no radiation; is a reliable method, especially for detecting aneurysms, arterial narrowing, and arteriovenous malformations. |
| Procedure | The patient lies in the MRI scanner; in some cases, a contrast agent (usually gadolinium) can be injected intravenously to visualize vessels more clearly. Imaging takes about 15 minutes. |
| Use of Contrast Agent | Generally safe, but should be used with caution in patients with renal insufficiency; gadolinium contrast is preferred in patients with good kidney function. |
| Side Effects | Very rarely, allergic reactions to the contrast agent may occur; there may be restrictions in the MRI scanner for people with metal implants. |
| Diagnosed Conditions | Used to evaluate conditions such as aneurysm, vascular occlusion, arterial narrowing, vascular malformation, blood flow disorders, and vascular dissections. |
| Alternative Methods | CT angiography, digital subtraction angiography (DSA); especially preferred in emergencies or when more detailed imaging is needed. |
| Associated Diseases | Aneurysm, stroke, vascular occlusion, peripheral artery disease, renal artery stenosis, vascular malformations. |
| Follow-up and Monitoring | Repeat MRA can be performed to monitor treated vascular diseases and assess recovery after treatment. |
| Preparation and Precautions | If the patient has metal or electronic implants, suitability for MRI must be assessed; in some cases, fasting may be necessary. |
Prof. Dr. Özgür KILIÇKESMEZ Prof. Dr. Kılıçkesmez holds the Turkish Radiology Competency Certificate, the Turkish Interventional Radiology Competency Certificate, Stroke Treatment Certification, and the European Board of Interventional Radiology (EBIR). In his academic career, he won the Siemens Radiology First Prize in 2008.
Interventional Radiology / Interventional Neuroradiology
What Is MR Angiography (MRA) and How Does It Work?
MR Angiography (MRA) is a special magnetic resonance imaging method that visualizes blood vessels in detail. Unlike conventional angiography, MRA is a non-invasive method and does not require a catheter. MRA uses magnetic fields and radio waves to produce detailed vascular images without the need for ionizing radiation. By using strong magnetic fields, it aligns hydrogen atoms to examine the structure of blood vessels. Then, radio waves are sent, and the energy emitted by these atoms is captured and converted into detailed images.
MRA uses two main techniques: contrast-enhanced MRA and non-contrast MRA. In contrast-enhanced MRA, a gadolinium-based contrast agent is used to highlight the vessels brightly. However, gadolinium may pose a risk for patients with kidney problems. Therefore, non-contrast MRA techniques have been developed. Non-contrast MRA uses TOF and phase contrast (PC) techniques. These techniques use the movement of blood to separate vessels from surrounding tissues, making them safer for patients with kidney problems.
What Diseases Can MRA Diagnose?
MR Angiography (MRA) is a powerful tool in diagnosing a variety of vascular disorders. MRA is effective in evaluating many different vascular issues and is critical for early diagnosis. Common vascular diseases diagnosed with MRA include:
- Arterial Occlusions (Atherosclerosis): Leads to narrowing of arteries due to plaque buildup; occurs in coronary, carotid, and peripheral arteries. This condition can cause heart disease, stroke, or peripheral artery disease (PAD).
- Aneurysms: Abnormal ballooning in the vessel wall. They can especially be found in the brain, heart (aorta), and renal arteries. Early diagnosis can prevent life-threatening complications such as aneurysm rupture.
- Stenosis (Narrowing of Arteries): A condition that leads to arterial narrowing. It is commonly associated with diseases such as renal artery stenosis or carotid artery stenosis. This increases the risk of hypertension, kidney failure, and stroke.
- Pulmonary Embolism and Pulmonary Vascular Occlusions: Used to detect blockages in the pulmonary vessels. Pulmonary embolism blocks blood flow to the lungs and poses a life-threatening risk.
- Congenital Heart Diseases: Effective in diagnosing congenital abnormalities in heart structure. Used in the diagnosis of congenital heart problems such as aortic coarctation.
- Peripheral Artery Disease (PAD): Detects arterial blockages, especially in the legs. This is important for evaluating blood flow and planning treatment options.
- Aortic Dissection: A life-threatening condition in which blood flow occurs between the layers of the aorta and can be diagnosed by MRA.
How Is MRA Different from Conventional Angiography and Other Imaging Methods?
MRA differs from other imaging techniques in several important ways. First, MRA offers a safe option for patients since it is non-invasive and radiation-free. Unlike conventional angiography, which requires catheter insertion, MRA provides detailed images of blood vessels without ionizing radiation. This is a significant advantage for children, pregnant women, or patients who require frequent imaging. In contrast, CT Angiography (CTA) involves X-rays and radiation, which may pose a risk.
MRA can be performed with or without gadolinium-based contrast agents. While gadolinium improves image quality, it carries a risk of nephrogenic systemic fibrosis in patients with kidney problems and should be used with caution. In such cases, non-contrast MRA is a safer alternative. CTA usually requires iodine-based contrast agents, which can also be risky for patients with poor kidney function.
Another important advantage of MRA is its ability to provide high soft tissue contrast. It visualizes complex vascular structures in detail, especially in cerebral vessels or peripheral arteries. While CTA offers high-resolution images, it is not as effective as MRA in distinguishing soft tissues.
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What Should Patients Expect During the MRA Procedure?
During the MRA procedure, patients follow several important preparation and screening steps. First, all metal objects must be removed before scanning because the magnetic field is affected by metal objects. The patient is required to remove jewelry, watches, and other metal items and wear a hospital gown. In some cases, an intravenous contrast dye may be administered to better visualize vessels; this is usually painless and only causes mild discomfort. Patients with claustrophobia may receive sedation for relaxation and, in this case, may need someone to accompany them home afterward.
During scanning, the patient is placed on a sliding table inside the MRI machine. The scanner makes loud knocking or banging noises throughout the imaging process, so earplugs or headphones are provided. To prevent blurry images, it is important for the patient to remain still, and sometimes short breath-holding may be required. The scan duration is usually between 15 and 30 minutes, but in some cases, it may take up to two hours.
There is usually no recovery time after the scan, and outpatients can leave as soon as the procedure is complete. If a contrast agent is used, rare side effects such as a metallic taste, nausea, or mild warmth at the scanned area may occur. The radiologist may briefly observe the patient to see if further scans are needed and then allow the patient to leave.
Are There Any Risks or Side Effects Associated with MRA?
Although Magnetic Resonance Angiography (MRA) is considered safe because it does not involve ionizing radiation, there are some risks and side effects. When contrast agents are used, especially gadolinium-based contrast agents (GBCA), some side effects may occur. Mild reactions are common, but rarely serious anaphylactic reactions can occur. Additionally, gadolinium deposition disease (GDD), resulting from the accumulation of GBCAs in the body, is a potential long-term risk. This may manifest as skin thickening or hardening. The risk of nephrogenic systemic fibrosis (NSF) is increased especially in patients with renal insufficiency.
GBCA use should be cautious in patients with kidney failure. Alternative contrast agents or non-contrast MRA techniques are preferred for these patients. Also, caution should be exercised in patients with certain metal implants. Strong magnetic fields may affect or dislodge devices such as pacemakers or cochlear implants. However, newer implants have significantly reduced these risks.
Frequently Asked Questions
Why is MR angiography requested?
MRA (Magnetic Resonance Angiography) is requested to evaluate vessels non-invasively. It is especially used to detect abnormalities such as aneurysms, narrowings, occlusions, arteriovenous malformations, and atherosclerotic diseases. It is widely preferred for examining the vessels of the brain, neck, heart, chest, abdomen, pelvis, and limbs, assisting in the diagnosis and treatment planning of various vascular diseases.
How long does MR angiography take?
The duration of Magnetic Resonance Angiography (MRA) varies depending on the area being examined and the complexity of the procedure. In general, the procedure takes about 10-30 minutes. If multiple vessels are examined, the full scan may take up to one hour. Once imaging begins, the entire study is usually completed in about 60 minutes.
Is MR angiography performed with contrast?
Magnetic Resonance Angiography (MRA) can be performed with or without a contrast agent. Contrast-enhanced MRA (CE-MRA) involves intravenous administration of gadolinium-based contrast agents to improve vessel visualization. Non-contrast MRA techniques include Time-of-Flight (TOF) and Phase Contrast (PC) methods, which do not require contrast agents. The chosen method depends on the clinical scenario and the patient’s condition.
What is cranial MR angiography?
Cranial magnetic resonance angiography (MRA) is a non-invasive imaging technique that visualizes the blood vessels inside the brain. Using the principles of magnetic resonance imaging (MRI), it provides detailed images of intracranial arteries and veins and helps diagnose conditions such as aneurysm, narrowing, and vascular malformations. There are various techniques in MRA, such as time-of-flight (TOF) and phase contrast (PC); each has its own indications and limitations. Advances in MRA have increased the accuracy and clinical benefit of evaluating intracranial vascular abnormalities.
Is MR angiography with contrast?
Yes, MRI angiography is often performed with contrast. In this method, gadolinium-based contrast agents are intravenously administered to make the vessels appear brighter in images. These agents shorten the T1 relaxation time of blood, allowing for detailed visualization of vascular structures.
Does angiography involve radiation?
Magnetic Resonance Angiography (MRA) does not involve radiation. Instead, it uses a strong magnetic field and radio waves to generate detailed images of blood vessels. Therefore, MRA differs from other imaging methods such as computed tomography angiography (CTA) that use ionizing radiation. MRA is frequently preferred for vascular imaging, especially in patients who are concerned about radiation exposure.
Is MR angiography invasive?
Magnetic Resonance Angiography (MRA) is a non-invasive imaging technique that uses magnetic fields and radio waves to visualize blood vessels. Unlike conventional angiography, this method does not require the insertion of a catheter into the body, making it much less invasive and painless. MRA can be performed with or without contrast agents and is a suitable option for patients allergic to gadolinium-based contrast agents. It is frequently used to assess vascular anatomy in different body regions and detect possible problems.
Interventional Radiology and Neuroradiology Speaclist Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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