Medical Policy



Subject: Magnetic Resonance Angiography of the Spinal Canal
Document #: RAD.00055 Current Effective Date:    03/29/2017
Status: Revised Last Review Date:    02/02/2017

Description/Scope

This document addresses the use of magnetic resonance angiography for imaging spinal canal vasculature. Magnetic resonance angiography is a form of magnetic resonance imaging technology which provides visualization of vascular anatomy and pathology.

Position Statement

Medically Necessary: 

Magnetic resonance angiography of the spinal canal is considered medically necessary in individuals with known cases of spinal cord arteriovenous fistula or arteriovenous malformation.

Investigational and Not Medically Necessary:

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

Rationale

Vascular malformations of the spine are commonly categorized into types of arteriovenous fistulas (AVFs) or arteriovenous malformations (AVMs). Applications for magnetic resonance angiography (MRA) of the spinal canal include evaluation of known cases of spinal AVFs or spinal AVMs. These vascular lesions are usually first diagnosed by magnetic resonance imaging (MRI). Computed tomography angiography (CTA) of the spinal vasculature may also be necessary to define the exact location and type of vascular abnormality. If 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. Contrast media may be used to enhance the images obtained in MRA; however, the use of these agents is not always necessary.

Outcome data for MRA of the spinal canal are limited to studies primarily focusing on the evaluation of AVFs or AVMs (Binkert, 1999; Mull, 2007; Saraf-Lavi, 2002). Mull and colleagues (2007) investigated the validity of MRA for identification of spinal arteriovenous abnormalities. Thirty-four individuals with suspected AV shunts underwent a contrast enhanced spinal cord MRA followed by digital subtraction angiography (DSA). Referral for the MRA was based on previous MRI findings and clinical data. The level and side of the suspected spinal dural AVF and the feeding arteries in spinal AVMs were determined from the MRA and compared with DSA. Based on study results, the authors concluded they demonstrated that contrast enhanced MRA was able to visualize both pathologic and normal arteries and veins of the spinal cord.

In a case report and literature review, Sharma and Westesson (2008) noted that contrast-enhanced MRA visualized and localized the great anterior radiculomedullary artery (artery of Adamkievicz [AKA]) correctly. However, the authors also indicated that while the image quality of contrast-enhanced MRA was sufficient to detect the AKA, it proved to be inferior to the DSA.

Vargas and colleagues (2010) reported that the small size of structures in the spine (spinal cord 10-12 mm, spinal anterior artery 0.2-0.8 mm, AKA 1.0 mm) makes it difficult to perform MRA sequences of the spinal cord. In this case series, 17 individuals with suspected spinal cord vascular pathology (including AVFs and AVMs) were examined with dynamic MRA using a higher magnetic field (3 Tesla) than standard MRA to produce higher resolution images. All cases, with the exception of 3 performed to localize the AKA and 3 individuals with medullary cone ischemia, also had conventional angiography. All AVMs and dural fistulae identified with conventional angiography were also detected with MRA. The enhanced MRA technique used in this study enabled imaging of feeding arteries as well as anatomy and flow velocity of early venous drainage and classification of AVMs.

Additional studies are needed to demonstrate the efficacy of MRA of the spinal canal in applications other than for further evaluation of a known AVF or AVM. The technique of MRA of the spinal canal is evolving and its impact on health outcomes will continue to undergo review as new evidence-based studies are published.

Background/Overview

MRA is a technique for imaging vascular anatomy and pathology and is based on MRI technology. It employs special imaging pulse sequences that emphasize the motion of blood relative to surrounding stationary tissue, with the goal of minimizing the signal from tissue and enhancing the signal from moving blood. The technique used in MRA allows for short repetition times, resulting in rapid image acquisition and reduced signal from background tissue.

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 commonly with 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 congenital or acquired. Vascular malformations of the spine are commonly categorized into types of 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 congenital 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.

Definitions

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

Coding

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:

CPT  
72159 Magnetic resonance angiography, spinal canal and contents, with or without contrast material(s)
   
HCPCS  
C8931 Magnetic resonance angiography with contrast, spinal canal and contents
C8932 Magnetic resonance angiography without contrast, spinal canal and contents
C8933 Magnetic resonance angiography without contrast followed by with contrast, spinal canal and contents
   
ICD-10 Diagnosis  
I77.0 Arteriovenous fistula, acquired
Q27.39 Arteriovenous malformation, other site
Q27.9 Congenital malformation of peripheral vascular system, unspecified
Q28.8 Other specified congenital malformations of circulatory system

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

References

Peer Reviewed Publications:

  1. Backes WH, Nijenhuis RJ. Advances in spinal cord MR angiography.AJNR Am J Neuroradiol. 2008; 29(4):619-631.
  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. Krings T, Lasjaunias PL, Hans FJ, et al. Imaging in spinal vascular disease. Neuroimaging Clin N Am. 2007; 17(1):57-72.
  5. 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.
  6. Pattany PM, Saraf-Lavi E, Bowen BC. MR angiography of the spine and spinal cord. Top Magn Reson Imaging. 2003; 14(6):444-460.
  7. Rodesch G, Lasjaunias P. Spinal cord arteriovenous shunts: from imaging to management. Eur J Radiol. 2003; 46(3):221-232.
  8. 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.
  9. Sharma AK, Westesson PL. Preoperative evaluation of spinal vascular malformation by MR angiography: how reliable is the technique: case report and review of literature. Clin Neurol Neurosurg. 2008; 110(5):521-524.
  10. Unsrisong K, Taphey S, Oranratanachai K. Spinal arteriovenous shunts: accuracy of shunt detection, localization, and subtype discrimination using spinal magnetic resonance angiography and manual contrast injection using a syringe. J Neurosurg Spine. 2016; 24(4):664-670.
  11. Vargas MI, Nguyen D, Viallon M, et al. Dynamic MR angiography (MRA) of spinal vascular diseases at 3T. Eur Radiol. 2010; 20(10):2491-2495.

Government Agency, Medical Society, and Other Authoritative Publications:

  1. American College of Radiology. ACR Appropriateness Criteria® . Available at: http://www.acr.org/Quality-Safety/Appropriateness-Criteria. Accessed on December 21, 2016.
    • Myelopathy (2015).
Index

Arteriovenous Fistula (AVF)
Arteriovenous Malformation (AVM)
Magnetic Resonance Angiography (MRA)
MR Angiography (MRA)

Document History

Status

Date

Action

Revised 02/02/2017 Medical Policy & Technology Assessment Committee (MPTAC) review. Removed abbreviations from title of document and from Position Statement. Updated References section.
Reviewed 02/04/2016 MPTAC review. Updated References section. Removed ICD-9 codes from Coding section.
Reviewed 02/05/2015 MPTAC review. Updated References.
Reviewed 02/13/2014 MPTAC review.
Reviewed 02/14/2013 MPTAC review.
Reviewed 02/16/2012 MPTAC review. Updated Rationale.
Reviewed 02/17/2011 MPTAC review. Title, Description, Rationale, Background, References, and Index updated.
  01/01/2011 Updated Coding section; added HCPCS codes C8931, C8932, C8933.
Reviewed 02/25/2010 MPTAC review. Note below Description, Rationale and References updated.
Reviewed 02/26/2009 MPTAC review. Rationale, Background and References updated.
New 02/21/2008 MPTAC review. Initial document development.