LCD L34424: Magnetic Resonance Angiography

Magnetic resonance angiography (MRA) is a modern diagnostic technique based on the effect of nuclear magnetic resonance and is like magnetic resonance imaging (MRI). During the procedure, the device reads electromagnetic waves received during the oscillation of the nuclei of hydrogen atoms, after which the computer converts the information received into a three-dimensional image of the zone under study. MRA is utilized to carry out studies of arteries, veins and lymphatic vessels of any location, to carry out a detailed assessment of the state of vascular networks, to identify pathological changes in the early stages, and to determine the cause of the pathology. 1

The coverage criteria and definition of MRA are found in the CMS Internet-only Manual, Pub. 100-03, Medicare National Coverage Determinations (NCD) Manual, Chapter 1, Part 4, §220.2. MRA with or without contrast is considered appropriate when it can replace a more invasive test (e.g., contrast angiography) and reduce risk for beneficiaries. MRA is a covered indication for various diseases and abnormalities involving the arterial, venous and lymphatic systems. In addition, the services must be reasonable and necessary for the diagnosis or treatment of the specific patient involved.

The use of MRA would have the same contraindications as MRI and should not be used in patients with implanted ferromagnetic structures and electronic devices.

MRA encompasses several imaging techniques based on MRI developed for studying the arterial and venous systems. The benefits of an MRA in comparison to traditional angiography is that it is noninvasive, it lacks ionizing radiation exposure, it has the potential for a non-contrast examination, and it can produce high-resolution volumetric images. The MRA gadolinium contrast material is less likely to cause an allergic reaction than the iodine-based contrast materials used for computed tomography scanning.

An MRA is often indicated to evaluate the following abnormalities and conditions and is used for screening 1 and monitoring purposes 1 : arterial aneurysm(s) 1 , arteriovenous malformations 2-4 , aortic coarctation 1 , aortic dissection 5,6 , cerebral stroke 1 , carotid artery disease 7,8 , peripheral atherosclerosis of the extremities 1 , congenital heart disease 1 , coronary artery disease and, if indicated, graft patency 9-12 , mesentery artery ischemia 13,14 , renal artery stenosis 15 , pulmonary embolism 16,17 , trigeminal neuralgia 18-20 , moyamoya disease 21,22 and intracranial aneurysms. 23,24

MRA has the same contraindications as MRI, including patients with implanted ferromagnetic structures and electronic devices. Such devices might include, but are not limited to the following: a cardiac implantable electronic device, mechanical metallic heart valves, metallic foreign bodies, implantable neurostimulation system, cochlear implants/ear implant, non-removable drug infusion pumps, catheters with metallic components, cerebral artery aneurysm clips which are non-MRI compatible, and tissue expanders with magnetic infusion ports. 25 Other contraindications for use of the contrast medium include a previous allergic or anaphylactic reaction to gadolinium. 26