Magnetic Resonance Angiography

Magnetic resonance angiography (MRA) is an application of magnetic resonance imaging (MRI) that provides visualization of blood flow, as well as images of normal and diseased blood vessels.

While MRA appears to be a rapidly developing technology, the clinical safety and effectiveness of this procedure for all anatomical regions has not been proven. As a result, Medicare will provide coverage for MRA on a limited basis. Below are the only indications for which Medicare coverage is allowed for MRA. All other uses of MRA will not be covered.

1. Head and Neck. Studies have proven that MRA is effective for evaluating flow in internal carotid vessels of the head and neck. However, not all potential applications of MRA have been proven effective. As a result, all of the following criteria must apply in order for Medicare to provide coverage for MRA of the head and neck:
   1. MRA is used to evaluate the carotid arteries, the circle of Willis, the anterior, middle or posterior cerebral arteries, the vertebral or basilar arteries or the venous sinuses;
   2. MRA is performed on patients with conditions of the head and neck for which surgery is anticipated and may be found to be appropriate based on the MRA. These conditions include, but are not limited to, tumor, aneurysms, vascular malformations, vascular occlusion or thrombosis. Within this broad category of disorders, medical necessity is the underlying determinant of the need for an MRA in specific diseases. The medical records should clearly justify and demonstrate the existence of medical necessity.
   3. MRA and contrast angiography (CA) are not expected to be performed on the same patient for diagnostic purposes prior to the application of anticipated therapy. Only one of these tests will be covered routinely unless the physician can demonstrate the medical need to perform both tests.
2. Peripheral Arteries of Lower Extremities. Studies have proven that MRA of peripheral arteries is useful in determining the presence and extent of peripheral vascular disease in lower extremities. This procedure is non-invasive and has been shown to find occult vessels in some patients for which those vessels were not apparent when CA was performed. Medicare will cover either MRA or CA to evaluate peripheral arteries of the lower extremities. However, both MRA and CA may be useful is some cases, such as:
   1. A patient has had CA and this test was unable to identify a viable run-off vessel for bypass. When exploratory surgery is not believed to be a reasonable medical course of action for this patient, MRA may be performed to identify the viable runoff vessel.
   2. A patient has had MRA, but the results are inconclusive.
3. Abdomen. Studies have proven that MRA is considered a reliable diagnostic tool for the pre-operative evaluation of patients who will undergo elective abdominal aortic aneurysm (AAA) repair. In addition, scientific data has revealed that MRA is considered comparable to CA in determining the extent of AAA, as well as evaluation of aortoilliac occlusion disease and renal artery pathology that may be necessary in the surgical planning for AAA repair. These studies also reveal that MRA could provide a net benefit to the patient. If preoperative angiography is not necessary, then patients are not exposed to the risks associated with invasive procedures, contrast media, end-organ damage or arterial injury. As with coverage of MRA for other anatomical sites, Medicare will provide coverage for either MRA or CA and not both tests on a routine basis. The physician may choose between CA or MRA for pre-operative imaging, after other tests such as computed tomography (CT) or ultrasound have been used to diagnose AAA and evaluate aneurysm size over time. However, both MRA and CA may be used when the physician can demonstrate the medical need for both tests to be performed, such as when a follow-up CA is necessary to clarify renal artery pathology, which might not be diagnosed definitively by an initial MRA.
4. Chest.
   1. Diagnosis of Pulmonary Embolism. Current scientific data has shown that diagnostic pulmonary MRAs are improving due to recent developments such as faster imaging capabilities and gadolinium-enhancement. However, these advances in MRA are not significant enough to warrant replacement of pulmonary angiography in the diagnosis of pulmonary embolism for patients who have no contraindication to receiving intravenous iodinated contrast material. Patients who are allergic to iodinated contrast material face a high risk of developing complications if they undergo pulmonary angiography or computed tomography angiography. Therefore, Medicare will cover MRA of the chest for diagnosing a suspected pulmonary embolism when it is contraindicated for the patient to receive intravascular iodinated contrast material.
   2. Evaluation of Thoracic Aortic Dissection and Aneurysm. Studies have shown that MRA of the chest has a high level of diagnostic accuracy for pre-operative and post-operative evaluation of aortic dissection of aneurysm. Depending on the clinical presentation, MRA may be used as an alternative to other non-invasive imaging technologies, such as transesophageal echocardiography and CT. Generally, Medicare will provide coverage only for MRA or for CA when used as a diagnostic test. However, if both MRA and CA of the chest are used, the physician must demonstrate the medical need for performing these tests.

While the intent of this policy is to provide reimbursement for either MRA or CA, HCFA is also allowing flexibility for physicians to make appropriate decisions concerning the use of these tests based on the needs of individual patients. HCFA anticipates, however, low utilization of the combined use of MRA and CA. As a result, HCFA encourages contractors to monitor the use of these tests and, where indicated, requires evidence of the need to perform both MRA and CA.

06/1999 - Expanded coverage for diagnostic evaluation of abdomen and chest, specifically for preoperative evaluation and to determine the extent of abdominal aortic aneurysm. Effective date 07/01/1999. (TN 117) 

05/1997 - Clarified when MRA of carotic vessels of the head and neck may be covered, and expanded coverage of MRA for use in evaluating the presence and extent of vascular disease in the peripheral vessels of the lower extremities. Effective date NA. (TN 99) 

10/1995 - Provided limited coverage of MRA procedures. Effective date 10/01/1995. (TN 80)