CT Angiography, Abdomen - CAM 706

Computed tomography angiography (CTA) generates images of the arteries that can be evaluated for evidence of stenosis, occlusion, or aneurysms. It is used to evaluate the arteries of the abdominal aorta and the renal arteries. CTA uses ionizing radiation and requires the administration of iodinated contrast agent, which is a potential hazard in patients with impaired renal function. Abdominal CTA is not used as a screening tool, e.g., evaluation of asymptomatic patients without a previous diagnosis.

Cross-sectional imaging (liver ultrasound with Doppler, CT or MRI) should be completed no more than a month prior to the transjugular intrahepatic portosystemic shunt (TIPS) to assess for vascular patency and look for hepatic masses or other problems that could complicate the procedure.

Post-procedure, an ultrasound of the liver is conducted a day after to assess shunt patency. Hepatic encephalopathy (HE) is the most common complication and usually occurs 2-3 weeks after insertion of TIPS. Unique complications may include intravascular hemolysis and infection of the shunt. Other complications can include capsule puncture, intraperitoneal bleed, hepatic infarction, fistula, hematobilia, thrombosis of stent, occlusion, or stent migration and may require cross-sectional imaging.

Follow-up and maintenance imaging if complications suspected include Doppler ultrasound to assess shunt velocity. If asymptomatic sonogram performed at 4 weeks post placement, then every 6 months to a year. The gold standard for shunt patency is portal venography, usually reserved if concern for shunt occlusion.

CTA and Renal Artery Stenosis: Renal artery stenosis is the major cause of secondary hypertension. It may also cause renal insufficiency and end-stage renal disease. Atherosclerosis is one of the common causes of this condition, especially in older patients with multiple cardiovascular risk factors and worsening hypertension or deterioration of renal function. CTA is used to evaluate the renal arteries and detect renal artery stenosis.

**NF1 may present with hypertension due to renal artery stenosis in children. All young patients (<30 year) with hypertension should be clinically screened for secondary causes of hypertension, including NF1, so that renal revascularization can be offered before permanent end organ damage has occurred (Duan, 2014).

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 (Khosa, 2013). Initial evaluation of AAA is accurately made by ultrasound. Ultrasound can detect and size AAA, with the advantage of being relatively inexpensive, noninvasive, and not requiring iodinate contrast. The limitations are that overlying bowel gas can obscure findings and the technique is operator-dependent.

Asymptomatic Aneurysms may require treatment when:

  • Diameter is > 2 cm
  • Identified during pregnancy
  • Multiple aneurysms are present
  • Hepatic transplant

Recommended intervals for initial follow-up imaging of ectatic aortas and abdominal aortas (follow-up intervals may vary depending on comorbidities and the growth rate of the aneurysm) from the white paper of the ACR Incidental Findings Committee II on vascular findings (Khosa, 2013):
2.5 – 2.9 cm:………….5 yr
3.0 – 3.4 cm:….………3 yr
3.5 – 3.9 cm:…….……2 yr
4.0 – 4.4 cm:……….…1 yr
4.5 – 4.9 cm:………….6 mo
5.0 – 5.5 cm:……….…3-6 mo

The Society of Vascular Surgery has different follow-up intervals for AAA (Chaikof, 2018):
>2.5 cm – <3 cm……..10 yr
3.0 – 3.9 cm……………3 yr
4.0 – 4.9 cm……………12 mo
5.0 – 5.4 cm……………..6 mo

The Society of Vascular Surgery recommends elective repair of AAA ≥ 5.5 cm in patients at low or acceptable surgical risk (Chaikof, 2018).

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 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. CTA in diagnosis of lower gastrointestinal bleeding is such an example (Clerc, 2017).

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 why 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 (Abe, 2010).


For evaluation of known or suspected abdominal vascular disease

Arterial Disease

  • Evaluation of known or suspected aortic aneurysm (also approve MRA pelvis) (Chaikof, 2018; Khosa, 2013; Kumar, 2017)
    • For screening, US is initial study
    • Known or suspected aneurysm > 2.5 cm AND equivocal or indeterminate ultrasound results
    • Prior imaging (e.g., ultrasound) demonstrating aneurysm >2.5 cm in diameter
    • Suspected complications of known aneurysm as evidenced by signs/symptoms such as new onset of abdominal or pelvic pain
    • Surveillance imaging every three years for diameter 2.0-2.9 cm and annually for 3.0-3.4 cm if doppler ultrasound is inconclusive. If > 3.5 cm, < 6 month follow-up (and consider intervention) (Wainhainen, 2019)

NOTE: For known or suspected abdominal aneurysm, CT/MRI should not be approvable without a contraindication to CTA/MRA (such as severe renal dysfunction, contrast allergy, or another specific reason CT/MRI is preferred).

  • Evidence of vascular abnormality seen on prior imaging studies and limited to the abdomen
  • For known large vessel diseases (abdominal aorta, inferior vena cava, superior/inferior mesenteric, celiac, splenic, renal or iliac arteries/veins), e.g., aneurysm, dissection, compression syndromes, arteriovenous malformations (AVMs), fistulas, intramural hematoma, and vasculitis limited to the abdomen
  • For suspected aortic dissection (approve CTA/MRA abdomen and pelvis)
  • For diagnosis or follow-up of visceral artery aneurysm (Ibrahim, 2018; Junternamms, 2018)
  • Suspected retroperitoneal hematoma or hemorrhage to determine vascular source of hemorrhage, in setting of trauma, tumor invasion, fistula or vasculitis, otherwise CT/MR abdomen and pelvis (rather than CTA/MRA) may be sufficient and the modality of choice for diagnosing hemorrhage (Ioannou, 2018)
  • For evaluation of suspected mesenteric ischemia/ischemic colitis (can approve CTA/MRA abdomen and pelvis) (ACR, 2018)
  • For patients with fibromuscular dysplasia (FMD), a one-time vascular study of the abdomen and pelvis (CTA or MRA) (Kadian-Dodov, 2016)
  • For patients with vascular Ehlers-Danlos syndrome or Marfan syndrome recommend a one-time study of the abdomen and pelvis (CTA/MRA)
  • For Loeys-Dietz imaging at least every two years (Chu, 2014)
  • For assessment in patients with spontaneous coronary artery dissection (SCAD) can be done at time of coronary angiography (also approve CTA pelvis) (Crousillat, 2020)
  • Vascular invasion or displacement by tumor
  • For evaluation of hepatic blood vessel abnormalities (aneurysm, hepatic vein thrombosis, stenosis post-transplant) after doppler ultrasound has been performed; to clarify or further evaluate ultrasound findings
  • For evaluation of known or suspected renal artery stenosis or resistant hypertension in the setting of normal renal function (with impaired renal function, eGFR <30, use US with Doppler) unrelated to recent medication demonstrated by any of the following (Akbeyaz, 2017; Bailey, 2018; Gulas, 2018; Hartman, 2009; Harvin, 2017; Mohammed, 2012; Tullus, 2010; Whelton, 2018):
    • Unsuccessful control after treatment with 3 or more (>2) anti-hypertensive medication at optimal dosing and one should be a diuretic
    • Acute elevation of creatinine after initiation of an angiotensin converting enzyme inhibitor (ACE inhibitor) or angiotensin receptor blocker (ARB)
    • Asymmetric kidney size noted on ultrasound
    • Onset of hypertension in a person younger than age 30 without any other risk factors or family history of hypertension**
    • Significant hypertension (diastolic blood pressure > 110 mm Hg) in a young adult (i.e., younger than 35 years) suggestive of fibromuscular dysplasia (Kong, 2018)
    • Diagnosis of a syndrome with a higher risk of vascular disease, such as neurofibromatosis, tuberous sclerosis, and Williams’ syndrome
    • New onset of hypertension after age 50
    • Acute rise in blood pressure in a person with previously stable blood pressures
    • Flash pulmonary edema without identifiable causes
    • Malignant or accelerated hypertension
    • Bruit heard over renal artery and hypertension
    • Abnormal/inconclusive renal doppler ultrasound

Venous Disease 

  • Suspected renal vein thrombosis in patient with known renal mass or from other causes (Mazhar, 2018)
  • Venous thrombosis if previous studies have not resulted in a clear diagnosis (add pelvis CTA/CTV when appropriate)
  • For May-Thurner syndrome (include pelvic CTV) (Ibrahim 2012; Wan-Ling, 2012)
  • Vascular invasion or displacement by tumor in the abdomen
  • For evaluation of portal venous system (hepatic portal system) after doppler ultrasound has been performed
  • For diffuse unexplained lower extremity edema with negative or inconclusive ultrasound (Hoshino, 2016)

Pre-operative evaluation 

  • For evaluation of transjugular intrahepatic portosystemic shunt (TIPS) when Doppler ultrasound indicates suspected complications (Darcy, 2012; Dariushnia, 2016; Farsad, 2014; Raissi, 2019)
  • Evaluation prior to interventional vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
  • For pre-transplant evaluation of either liver or kidney
  • Imaging of the deep inferior epigastric arteries for surgical planning (breast reconstruction surgery), include pelvic CTA/MRA (ACR, 2018)

Post-operative or post-procedural evaluation

  • 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 the peritoneal cavity
  • Follow-up for post-endovascular repair (EVAR) or open repair of abdominal aortic aneurysm (AAA) or abdominal extent of iliac artery aneurysms. Routine, baseline study (post-op/intervention) is warranted within 1-3 months (CTA abdomen and pelvis should be approved) (ACR 2018; Chaikof, 2018; Uberoi, 2011)
    • If asymptomatic at six (6)-month intervals for one (1) year, then annually
    • If symptomatic/complications related to stent graft – more frequent imaging may be needed
    • 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. 

Other Vascular indications

  • Suspected retroperitoneal hematoma or hemorrhage to determine vascular source of hemorrhage, in setting of trauma, tumor invasion, fistula or vasculitis; otherwise, CT/MR abdomen and pelvis (rather than CTA/MRA) may be sufficient and the modality of choice for diagnosing hemorrhage (Ioannou, 2018)
  • For evaluation of hepatic blood vessel abnormalities (aneurysm, hepatic vein thrombosis, stenosis post-transplant) after doppler ultrasound has been performed; to clarify or further evaluate ultrasound findings
  • Lower gastrointestinal hemorrhage: Active bleeding in a hemodynamically stable patient or non-localized intermittent bleeding as an alternative to Tc-99m RBC scan when colonoscopy did not localize the bleeding, is contraindicated, or unavailable (Clerc, 2017; Karuppasamy, 2021) 

Chest CTA/Abdomen/Pelvis CTA combo

  • For evaluation of extensive vascular disease involving the chest and abdominal cavities
  • For pre-op or preprocedural evaluation for Transcatheter Aortic Valve Replacement (TAVR) (Achenbach, 2012; ACR, 2018)
  • Acute aortic dissection (Barman, 2014)
  • Takayasu’s arteritis (Keser, 2014)
  • Marfans syndrome
  • Loeys-Dietz
  • Spontaneous coronary artery dissection (SCAD)
  • Vascular Ehlers-Danlos syndrome
  • Post-op complications (Bennet, 2017; Choudhury, 2017)
  • Significant post-traumatic or post-procedural vascular complications   


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Coding Section

Codes Number Description
CPT 74175

Computed tomographic angiography, abdomen, with contrast material(s), including noncontrast images, if performed, and image postprocessing

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive. 

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

"Current Procedural Terminology © American Medical Association.  All Rights Reserved" 

History From 2019 Forward 

11/01/2021  Annual review, no change to policy intent. Reorganizing policy for clarity. Updating description and overview. 
11/01/2020  Annual review, updating policy to include verbiage regarding compression syndrome, Ehlers Danlos syndrome, Loetz Dietz, May Thurner and combination studies for chest CTA/ abdomen and pelvis CTA. Also updating references. 
11/22/2019                   NEW POLICY
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