It is an expectation that all patients receive care/services from a licensed clinician. All appropriate supporting documentation, including recent pertinent office visit notes, laboratory data, and results of any special testing must be provided. If applicable: All prior relevant imaging results and the reason that alternative imaging cannot be performed must be included in the documentation submitted. 

Where a specific clinical indication is not directly addressed in this guideline, medical necessity determination will be made based on widely accepted standard of care criteria. These criteria are supported by evidence-based or peer-reviewed sources such as medical literature, societal guidelines and state/national recommendations.

Policy
IMPORTANT NOTE: 
Abdomen/Pelvis Magnetic Resonance Angiography (MRA) With Lower Extremity MRA Runoff Requests: Two authorization requests are required: one aAbdomen MRA, CPT code 74185, and one for lower extremity MRA, CPT code 73725 (a separate pelvic MRA request is not required). This will provide imaging of the abdomen, pelvis, and both legs. 

INDICATIONS FOR ABDOMEN MR ANGIOGRAPHY/MR VENOGRAPHY (MRA/MRV)
Abdominal Aortic Disease
Abdominal Aortic Aneurysm

• Asymptomatic known or suspected abdominal aortic aneurysms when prior ultrasound is inconclusive or insufficient AND when CT/CTA is contraindicated or cannot be performed
• Symptomatic known or suspected Abdominal Aortic Aneurysm^(1,2)
  • Symptoms may include:
    • Abrupt onset of severe sharp or stabbing pain in the chest, back or abdomen
    • Acute abdominal or back pain with a pulsatile or epigastric mass
    • Acute abdominal or back pain and at high risk for aortic aneurysm and/or aortic syndrome (risk factors include hypertension, atherosclerosis, prior cardiac or aortic surgery, underlying aneurysm, connective tissue disorder (e.g., Marfan syndrome, vascular form of Ehlers-Danlos syndrome, Loeys- Dietz syndrome), and bicuspid aortic valve)⁽³⁾

Aortic Syndromes
For initial diagnosis of suspected and follow-up of known aortic syndromes, including aortic dissection, intramural hematoma and penetrating atherosclerotic ulcer:

• Frequency for follow up is as clinically indicated

Postoperative Follow-up of Aortic Repair (1,2)
Follow-up for post-endovascular repair (EVAR) or open repair of AAA or abdominal extent of iliac artery aneurysms at the following intervals

• Routine, baseline post-EVAR study when CT/CTA is contraindicated or cannot be performed:
  • Within one month of procedure
  • Continued follow up imaging at the following intervals:
    • If no endoleak or sac enlargement is seen:
      • Annually monitor with ultrasound
        • When US is abnormal or insufficient CT/MR can be used to monitor annually
      • Every 5 years monitor with CT/MR
    • If type II endoleak or sac enlargement is seen at any point in time (US not needed):
      • Monitor every 6 months x 2 years, then annually (does not require US)
• Routine follow up after open repair of AAA when CT/CTA is contraindicated or cannot be performed:
  • Within 1 year postoperatively then
  • Annually monitor with ultrasound
    • When US is abnormal or insufficient CT/MR can be used to monitor annually
  • Every 5 years monitor with CT/MR
• If symptomatic or imaging shows increasing, or new findings related to stent graft –

more frequent imaging may be needed as clinically indicated

• Suspected complication such as: new onset lower extremity claudication, ischemia, or reduction in ABI after aneurysm repair

Renal Artery Stenosis
In a patient with hypertension unrelated to recent medication use AND prior abnormal or inconclusive ultrasound AND any of the following:(4,5,6)

• Onset of hypertension prior to the age of 30 without a family history of hypertension and when there is suspicion of fibromuscular dysplasia or a vasculitis
• Failure to obtain adequate blood pressure control on 3 antihypertensive medications, including one diuretic
• Recurrent episodes of sudden onset of congestive heart failure (also known as cardiac disturbance syndrome; may have normal left ventricular function)
• Renal failure of uncertain cause with normal urinary sediment and < 1g of urinary protein per day
• Coexisting diffuse atherosclerotic vascular disease, especially in heavy smokers
• Acute elevation of creatinine after initiation of an angiotensin converting enzyme inhibitor (ACE inhibitor) or angiotensin receptor blocker (ARB)
• Malignant or difficult to control hypertension and unilateral small kidney size (noted on prior imaging)
• New onset of difficult to control or labile hypertension after age 55
• Abdominal bruit lateralizing to one side of the abdomen
• Diagnosis of a syndrome with a higher risk of vascular disease, such as neurofibromatosis⁽⁷⁾ and Williams’ syndrome⁽⁸⁾

Ischemia or Hemorrhage

• To determine the vascular source of retroperitoneal hematoma or hemorrhage when CT is insufficient to determine the source and CTA is contraindicated or cannot be performed(CT rather than MRA/CTA is the modality of choice for diagnosis) hemorrhage)⁽⁹⁾
• Evaluation of known or suspected mesenteric ischemia/ischemic colitis when CTA is contraindicated or cannot be performed⁽¹⁰⁾

Other Vascular Abnormalities

• Suspected complications of known aneurysm as evidenced by clinical findings such as new onset of abdominal pain

Venous Disease

• Suspected venous thrombosis (including renal vein thrombosis and/or portal venous thrombosis) if previous studies (such as ultrasound) have not resulted in a clear diagnosis⁽¹⁶⁾
• Known/suspected May-Thurner syndrome (iliac vein compression syndrome) when CTV is contraindicated or cannot be performed^(17,18)
• Evaluation of suspected pelvic vascular disease or pelvic congestive syndrome when ordered in addition to Pelvis MRA/MRV with prior inconclusive ultrasound⁽¹⁹⁾

Peripheral Vascular Disease (20,21,22,23)
For evaluation of known or suspected lower extremity arterial disease when CTA is contraindicated or cannot be performed AND Abdomen MRA is ordered in addition to lower extremity MRA(s):

• For known or suspected peripheral arterial disease (such as claudication, or clinical concern for vascular causes of ulcers) when non-invasive studies (pulse volume recording, ankle-brachial index, toe brachial index, segmental pressures, or doppler ultrasound) are abnormal or indeterminate OR
• For critical limb ischemia with ANY of the below clinical signs of peripheral artery disease (prior ultrasound is NOT needed; if done and negative, MRA should still be approved)^(24,25)
  • Ischemic rest pain
  • Tissue Loss
  • Gangrene
• After stenting or surgery with signs of recurrent symptoms, abnormal ankle/brachial index, abnormal or indeterminate arterial Doppler, or abnormal or indeterminate pulse volume recording

NOTE: When the criteria above are met, two separate authorizations are required: Abdomen MRA (CPT 74185) and one Lower Extremity MRA (CPT 73725). This will provide imaging of the abdomen, pelvis and both legs. A separate Pelvis MRA authorization is NOT required.
Only one Lower Extremity MRA is required (not two).

Evaluation of Tumor

• Prior to Y90 treatment⁽²⁷⁾
• For imaging of the deep inferior epigastric arteries prior to breast reconstructive surgery

Pre-Operative Evaluation and/or Pre-Procedural Evaluation

• Evaluation of transjugular intrahepatic portosystemic shunt (TIPS) when Doppler ultrasound indicates suspected complication(s)^(28,29,30)
• Evaluation prior to interventional vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
• Evaluation prior to endovascular aneurysm repair (EVAR)
• Evaluation prior to Transcatheter Aortic Valve Replacement (TAVR) when CTA is contraindicated or cannot be performed⁽³¹⁾
• For imaging of the deep inferior epigastric arteries prior to breast reconstructive surgery⁽²²⁾
• Evaluation of vascular anatomy prior to solid organ transplantation
• Evaluation of anatomy (lower pole crossing vessel) prior to UPJ (ureteropelvic junction) obstruction surgery
• Prior to Y90 treatment⁽²⁷⁾

Post-Operative Evaluation and/or Post-Procedural Evaluation
Unless otherwise specified within the guideline:

• Follow-up study may be needed to help evaluate a patient’s progress after treatment, procedure, intervention, or surgery. Documentation requires a medical reason that clearly indicates why additional imaging is needed for the type and area(s) requested.
• Evaluation of endovascular/interventional abdominal vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
• Evaluation of post-operative complications, e.g., pseudoaneurysms, related to surgical bypass grafts, vascular stents, and stent-grafts in abdomen

Genetic Syndromes and Rare Diseases

• One-time vascular study from brain to pelvis
• Vascular Ehlers-Danlos syndrome:^(34,35)
  • At diagnosis and then every 18 months
  • More frequently if abnormalities are found
• Marfan syndrome:⁽³⁶⁾
  • At diagnosis and then every 3 years
  • More frequently (annually) if EITHER: history of dissection, dilation of aorta beyond aortic root OR aortic root/ascending aorta are not adequately visualized on TTE (i.e., advanced imaging is needed to monitor the thoracic aorta)^(2,37)
• Loeys-Dietz:⁽³⁸⁾
  • At diagnosis and then every two years
  • More frequently if abnormalities are found
• Williams Syndrome:⁽⁸⁾
  • When there is concern for vascular disease (including renal artery stenosis) based on abnormal exam or imaging findings (such as diminished pulses, bruits or signs of diffuse thoracic aortic stenosis)
• Neurofibromatosis Type 1 (NF-1):⁽⁷⁾
  • Development of hypertension (including concern for renal artery stenosis)
• Takayasu's Arteritis:⁽³⁹⁾
  • For evaluation at diagnosis then as clinically indicated
• For other syndromes and rare diseases not otherwise addressed in the guideline, coverage is based on a case-by-case basis using societal guidance

Combination Studies
Abdomen MRA and Abdomen MRI or CT

• When needed for clarification of vascular invasion from tumor (including suspected renal vein thrombosis)

Chest MRA/Abdomen MRA and/or Lower Extremity MRA

• To evaluate for an embolic source of lower extremity vascular disease. Echocardiography is also often needed, since the heart is the most commonly reported source of lower extremity emboli, accounting for 55 to 87 percent of events.

Abdomen MRI (or CT) and Abdomen MRA (or CTA) and PET

• Prior to Y90 treatment⁽²⁷⁾

Abdomen/Pelvis MRA

• As a dedicated CPT code does not exist for Abdomen and Pelvis MRA, when a disease process is reasonably expected to involve both the abdomen and pelvis AND the guideline criteria have been met, two separate authorizations are required: Abdomen MRA (CPT code 74185) and Pelvis MRA (CPT 72198)

Brain/Neck/Chest/Abdomen/Pelvis MRA

• For patients with fibromuscular dysplasia (FMD), a one-time vascular study from brain to pelvis^(32,33)
• Vascular Ehlers-Danlos syndrome: At diagnosis and then every 18 months; more frequently if abnormalities are found^(34,35)
• Loeys-Dietz: at diagnosis and then every two years, more frequently if abnormalities are found⁽³⁸⁾
• For assessment in patients with spontaneous coronary artery dissection (SCAD), can be done at time of coronary angiography⁽¹⁵⁾

Chest/Abdomen/Pelvis MRA

• Significant post-traumatic or post-procedural vascular complications reasonably expected to involve the chest, abdomen and pelvis

Neck/Chest/Abdomen/Pelvis MRA

• Takayasu's Arteritis: For evaluation at diagnosis then as clinically indicated⁽³⁹⁾

Further Evaluation of Indeterminate Findings on Prior Imaging
Unless follow-up is otherwise specified within the guideline

• For initial evaluation of an inconclusive finding on a prior imaging report that requires further clarification
• One follow-up exam of a prior indeterminate MR/CT finding to ensure no suspicious interval change has occurred. (No further surveillance unless specified as highly suspicious or change was found on last follow-up exam.)

Rationale
BACKGROUND
Abdominal MRA is not used as a screening tool, e.g., evaluation of asymptomatic patients without a previous diagnosis.

Abdominal Aneurysms and General Guidelines for Follow- up
The normal diameter of the suprarenal abdominal aorta is 3.0 cm and that of the infrarenal is
2.0 cm. Aneurysmal dilatation of the infrarenal aorta is defined as diameter ≥ 3.0 cm or dilatation of the aorta ≥ 1.5x the normal diameter.(41) Evaluation of AAA can be accurately made by ultrasound which can detect and size AAA with the advantage of being relatively inexpensive, noninvasive, and not requiring iodinated contrast. The limitations are overlying bowel gas which can obscure findings and the technique is operator dependent. Ultrasound is used to screen for and to monitor aneurysms*. CT is used when US is inconclusive or insufficient. When there are suspected complications, complex anatomy and/or surgery is planned, CTA/MRA is preferred.

Risk factors for AAA include smoking history, age, male gender, family history of AAA (first degree relative) and personal history of vascular disease. Risk factors for rupture include female gender, large initial aneurysm diameter, low FEV, current smoking history, elevated mean blood pressure and patients on immunosuppression after major organ transplantation. The Society of Vascular Surgery recommends elective repair of AAA ≥ 5.5 cm in patients at low or acceptable surgical risk.(1)

Ultrasound Screening Intervals*

• Aneurysm size 2.5–3 cm, every 10 years
• Aneurysm size 3.0–3.9 cm, every 3 years
• Aneurysm size 4.0-4.9 cm, annually⁽²⁾
• Aneurysm size 5.0-5.4 cm, every 6 months

MRA and Renal Vein Thrombosis
Renal vein thrombosis is a common complication of nephrotic syndrome and often occurs with membranous glomerulonephritis. Gadolinium-enhanced MRA can demonstrate both the venous and arterial anatomy and find filling defects within renal veins. The test can be used for follow-up purposes as it does not use ionizing radiation.

MRI/CT and Acute Hemorrhage
MRI is not indicated and MRA/MRV (MR Angiography/Venography) is rarely indicated for evaluation of intraperitoneal or retroperitoneal hemorrhage, particularly in the acute setting. CT is usually the study of choice due to its availability, speed of the study, and less susceptibility to artifact from patient motion. Advances in technology have allowed conventional CT to not just detect hematomas but also the source of acute vascular extravasation. In special cases, finer vascular detail to assess the specific source vessel responsible for hemorrhage may require the use of CTA (e.g., CTA in diagnosis of lower gastrointestinal bleeding). (42)

MRA/MRV is often utilized in non-acute situations to assess vascular structure involved in atherosclerotic disease and its complications, vasculitis, venous thrombosis, vascular congestion, or tumor invasion. Although some of these conditions may be associated with hemorrhage, it is usually not the primary reason MRI/MRA/MRV is selected for the evaluation. A special condition where MRI may be superior to CT for evaluating hemorrhage is to detect an underlying neoplasm as the cause of bleeding.(9)

Contraindications and Preferred Studies

• Contraindications and reasons why a CT/CTA cannot be performed may include: impaired renal function, significant allergy to IV contrast, pregnancy (depending on trimester)
• Contraindications and reasons why an MRI/MRA cannot be performed may include: impaired renal function, claustrophobia, non-MRI compatible devices (such as non- compatible defibrillator or pacemaker), metallic fragments in a high-risk location, patient exceeds wight limit/dimensions of MRI machine

References