Magnetic Resonance Angiography (MRA) is a form of magnetic resonance (MR) imaging which provides visualization of blood flow, as well as images of normal and diseased blood vessels. MRA is generally considered noninvasive because it does not require the use of contrast media. Though contrast media may be used to enhance the images obtained in MRA, the use of these agents is not necessary. MRA of the spinal canal is being considered as a tool for the detection and evaluation of spinal cord vascular pathology.

Note: Please see the following related documents for additional information:

• CG-RAD-08 CTA/MRA-Brain and Neck
• CG-RAD-09 CTA/MRA of the Thorax, Abdomen and Extremities
• RAD.00035 Contrast-Enhanced Cardiac Computed tomography Angiography (CTA) and Cardiac Magnetic Resonance Angiography (MRA)

Medically Necessary:

MRA of the spinal canal is considered medically necessary in patients with known cases of spinal cord arteriovenous fistula (AVF) and arteriovenous malformation (AVM). 

Investigational and Not Medically Necessary:

MRA of the spinal canal is considered investigational and not medically necessary for all other indications.

Applications for MRA of the spinal canal include evaluation of spinal arteriovenous fistula (AVF) and arteriovenous malformation (AVM). These vascular lesions are usually diagnosed by MRI. Intra-arterial digital subtraction angiography (DSA) of the spinal vasculature may be necessary to define the exact location and type of vascular abnormality. When an AVF or AVM has been detected an MRA of the spinal canal may be used to further define the vascular malformation and decide on appropriate treatment.

Current evidence suggests MRA of the spinal canal is a promising technique; however, the outcome data in other settings which would determine the efficacy of this technology is limited to studies involving a small number of patients (Binkert, 1999, Mull, 2007, Saraf-Lavi, 2002). Additional studies are needed to demonstrate the efficacy of MRA of the spinal canal in applications other than testing of a known AVF or AVM. The technique of MRA of the spinal canal and its impact on health outcomes will continue to undergo review, as new evidence-based studies are published.

The spinal canal is the space in the vertebrae that contains the spinal cord and spinal nerves throughout the length of the vertebral column. Segmental arteries supply the spine, including the vertebral bodies, paraspinal muscles, dura, nerve roots, and the spinal cord with blood. The venous drainage of the cord is via radially symmetric intrinsic spinal cord veins and small superficial veins. These veins usually follow the arteries but have many anastomoses that create a network with commonly more than one anterior and posterior vein.

Arterial and venous spinal cord vascular malformations are blood vessel disorders that affect the spinal cord. Spinal vascular malformations can be differentiated, similar to vascular malformations of the brain, into inborn lesions and acquired nerve root lesions. The most common spinal vascular malformations are AVFs and AVMs. Most AVFs are located in the thoracolumbar region. They are thought to be acquired lesions, however the exact etiology is not known. Spinal cord AVMs are fed by spinal cord arteries and drained by spinal cord veins. These are thought to be inborn lesions. Treatment options for both AVMs and AVFs include surgery. MRI should constitute the first diagnostic modality when spinal vascular diseases are suspected. Once an AVM or AVF has been detected, an MRA of the spinal canal may be used to assist in the evaluation and treatment planning of these vascular lesions.

The role of the MRA to evaluate other vascular lesions of the spinal canal is evolving. Other vascular lesions of the spinal cord include arterial infarcts, hemangiomas and spinal cavernomas.

Magnetic resonance: the absorption of specific frequencies of radio and microwave radiation by atoms placed in a magnetic field, revealing molecular structure

Magnetic resonance angiography: a non-invasive radiological imaging technique that utilizes traditional MRI technology to provide detailed images of blood vessels

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Investigational and Not Medically Necessary:
For the procedure code listed above, when criteria are not met, for all other diagnoses, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

Peer Reviewed Publications: 

1. Backes WH, Nijenhuis RJ. Advances in spinal cord MR angiography.AJNR Am J Neuroradiol. 2008; 29(4):619-631. Epub 2008 Jan 17.
2. Binkert CA, Kollias SS, Valavanis A. Spinal cord vascular disease: characterization with fast three-dimensional contrast-enhanced MR angiography. AJNR Am J Neuroradiol. 1999; 20(10):1785-1793.
3. Bowen BC, Saraf-Lavi E, Pattany PM. MR angiography of the spine: update. Magn Reson Imaging Clin N Am. 2003; 11(4):559-584.
4. Mull M, Nijenhuis RJ, Backes WH, et al. Value and limitations of contrast-enhanced MR angiography in spinal arteriovenous malformations and dural arteriovenous fistulas. AJNR Am J Neuroradiol. 2007; 28(7):1249-1258.
5. Krings T, Lasjaunias PL, Hans FJ, et al. Imaging in spinal vascular disease. Neuroimaging Clin N Am. 2007; 17(1):57-72.
6. Rodesch G, Lasjaunias P. Spinal cord arteriovenous shunts: from imaging to management. Eur J Radiol. 2003; 46(3):221-232.
7. Saraf-Lavi E, Bowen BC, Quencer RM, et al. Detection of spinal dural arteriovenous fistulae with MR imaging and contrast-enhanced MR angiography: sensitivity, specificity, and prediction of vertebral level. AJNR Am J Neuroradiol. 2002; 23(5):858-867.

Arteriovenous Malformation (AVM)
Arteriovenous Fistula (AVF)

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