CT Angiography, Abdomen and Pelvis - CAM 708HB

Body CTA is a method used to characterize vascular anatomy, diagnose vascular diseases, and plan treatment. Following contrast thin section CT acquisition is utilized and timed to coincide with peak arterial and venous enhancement. Both multiplanar and 3D reconstructions can be reformatted.

Bruits — Blowing vascular sounds heard over partially occluded blood vessels. Abdominal bruits may indicate partial obstruction of the aorta or other major arteries such as the renal, iliac, or femoral arteries. Associated risks include but are not limited to renal artery stenosis, aortic aneurysm, atherosclerosis, AVM, or coarctation of aorta.

Peripheral Artery Disease (PAD) — Before the availability of computed tomography angiography (CTA), peripheral arterial disease was evaluated using CT and only a portion of the peripheral arterial tree could be imaged. Multi-detector row CT (MDCT) overcomes this limitation and provides an accurate alternative to CT and is a cost-effective diagnostic strategy in evaluating PAD. Abdominal arteries CTA (including runoff to the lower extremities) is the preferred study when evaluation of arterial sufficiency to the legs is part of the evaluation.

Lower GI Bleeding — Colonoscopy should be the initial diagnostic procedure for nearly all patients presenting with acute LGIB (strong recommendation, low-quality evidence). Hematochezia associated with hemodynamic instability should lead to consideration of a brisk UGIB source, especially in at-risk patients, such as those with a history of peptic ulcer disease or liver disease with portal hypertension and those using antiplatelet or anticoagulant medications, and an upper endoscopy should be performed. CTA is a reasonable first-line screening test if needed before angiography or emergent surgery.5

CTA and Abdominal Aortic Aneurysm — Endovascular repair is an alternative to open surgical repair of an abdominal aortic aneurysm. It has lower morbidity and mortality rates and is minimally invasive. In order to be successful, it depends on precise measurement of the aneurysm and involved vessels. CTA with 3D reconstruction is useful in obtaining exact morphologic information on abdominal aortic aneurysms. CTA is also used for the detection of postoperative complications of endovascular repair.

CTA and Abdominal Aortic Aneurysm — 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.2 Evaluation of AAA can be accurately made by ultrasound. Ultrasound can detect and size AAA, with the advantage of being relatively inexpensive, noninvasive, and not requiring iodinated contrast. The limitations are that overlying bowel gas 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, annually36
  • Aneurysm size 5.0 – 5.4 cm, every 6 months

Iliac Artery Aneurysms — Follow-up asymptomatic incidentally detected iliac artery aneurysms:
The definition of an iliac artery aneurysm is dilatation to more than 1.5 times its normal diameter, in general ≥ 18 mm in men and ≥ 15 mm in women, an internal iliac artery > 8 mm. Surveillance is extrapolated from AAA surveillance and can be done by Doppler ultrasound or CTA if hard to visualize by ultrasound.4

CTA and Thoracic Aorta Endovascular Stent-Grafts — CTA is an effective alternative to conventional angiography for postoperative follow-up of aortic stent grafts. It is used to review complications after thoracic endovascular aortic repair. CTA can detect luminal and extraluminal changes to the thoracic aortic after stent-grafting and can be performed efficiently with fast scanning speed and high spatial and temporal resolution.

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.14 In this case, colonoscopy should be the initial diagnostic procedure.

MRA/MRV is often utilized in non-acute situations to assess vascular structure involved in atherosclerotic disease and its complications, such as 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.37

General Information

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.

IMPORTANT NOTE: When vascular imaging of the aorta and both legs, i.e., CTA aortogram and runoff is desired (sometimes incorrectly requested as abdomen/pelvis CTA & lower extremity CTA runoff), only one authorization request is required, using CPT code 75635, Abdominal Arteries CTA. This study provides for imaging of the abdomen, pelvis, and both legs. The CPT code description is CTA aorto-iliofemoral runoff; abdominal aorta and bilateral ilio-femoral lower extremity runoff.

When vascular imaging of the aorta and both legs, i.e., CTA aortogram and runoff is desired (sometimes incorrectly requested as abdomen/pelvis CTA & lower extremity CTA runoff), only one authorization request is required, using CPT code 75635, Abdominal Arteries CTA. This study provides for imaging of the abdomen, pelvis, and both legs. The CPT code description is CTA aorto-iliofemoral runoff; abdominal aorta and bilateral ilio-femoral lower extremity runoff.

When separate requests for CTA abdomen and CTA Pelvis are encountered for processes involving both the abdomen and pelvis (but do NOT need to include legs/runoff), they need to be resubmitted as a single abdomen/pelvis CTA (to avoid unbundling). Otherwise, the exam should be limited to the appropriate area (i.e., abdomen OR pelvis) that includes the area of concern.


For evaluation of known or suspected abdominal/pelvis vascular disease

Arterial Disease

Abdominal Aortic Aneurysm (AAA):

  • For asymptomatic known or suspected abdominal aortic aneurysms, ultrasound should be done prior to advanced imaging. Only when the ultrasound is inconclusive, is advanced imaging needed (see Background for ultrasound screening intervals).
  • For symptomatic known or suspected AAA (such as recent-onset abdominal pain or back pain, particularly in the presence of a pulsatile or epigastric mass, suspected dissection or significant risk factors for AAA) CTA/MRA is appropriate and generally preferred over CT/MRI. (If contrast is contraindicated or other clinical indications for abdomen and/or pelvic imaging are present, then CT/MR may be approved rather than CTA/MRA).
  • If there is known complex vascular anatomy, CTA/MRA may be needed.

Other vascular abnormalities seen on prior imaging studies:

  • Initial evaluation of inconclusive vascular findings on prior imaging
  • Follow-up of known visceral vascular conditions (such as aneurysm, dissection, compression syndromes, arteriovenous malformations (AVMs), fistulas, intramural hematoma, and vasculitis) (pelvis may also be approved if needed based on location of abnormality)
    • Hepatic vascular abnormalities after ultrasound has been performed to clarify or further evaluate findings
  • For assessment in patients with spontaneous coronary artery dissection (SCAD), can be done at time of coronary angiography5
  • Vascular invasion or displacement by tumor (conventional CT or MRI also appropriate)6
  • For known large vessel diseases (inferior vena cava, superior/inferior mesenteric, celiac, splenic, renal or iliac arteries/veins), e.g., aneurysm/dissection (non-aortic disease), arteriovenous malformations (AVMs), and fistulas, intramural hematoma, and vasculitis7,8,9
    • Surveillance may be done with ultrasound at intervals similar to AAA, however, CTA/MRA rather than CT/MRI may be needed for non-aortic disease when ultrasound is inconclusive10

Vascular ischemia or hemorrhage:

  • To determine the vascular source of retroperitoneal hematoma or hemorrhage when CT is insufficient to determine the source of hemorrhage9,12
  • For evaluation of suspected mesenteric ischemia/ischemic colitis11
  • 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, or is contraindicated or unavailable5,6,14
  • For hemodynamically unstable patients15,16

For patients at increased risk for vascular abnormalities (CTA or MRA):

  • For patients with fibromuscular dysplasia (FMD), a one-time vascular study of the abdomen and pelvis13
  • For patients with vascular Ehlers-Danlos syndrome or Marfan syndrome, a one-time study of the abdomen and pelvis
  • For Loeys-Dietz, imaging at diagnosis and then every two years, more frequently if abnormalities are found (Imaging may include head, neck, chest, abdomen and pelvis)14,20 (MRA preferred due to cumulative radiation risk)

Venous disease

  • Venous thrombosis if previous studies have not resulted in a clear diagnosis
  • For suspected/known May-Thurner syndrome24,25
  • For evaluation of venous thrombosis in the inferior vena cava (IVC)17
  • Vascular invasion or displacement by tumor (if involves both the abdomen and pelvis (otherwise limit to either abdomen or pelvis as appropriate)
  • For evaluation of suspected pelvic vascular disease or pelvic congestive syndrome when findings on ultrasound are indeterminate (MR or CT venography may be used as the initial study for evaluating pelvic thrombosis or thrombophlebitis)
  • For unexplained lower extremity edema (typically unilateral or asymmetric) with negative or inconclusive ultrasound26

Pre-operative evaluation

  • Evaluation of interventional vascular procedures for luminal patency versus restenosis due to conditions such as atherosclerosis, thromboembolism, and intimal hyperplasia
  • Prior to repair of abdominal aortic aneurysm (AAA)
  • For imaging of the deep inferior epigastric arteries for surgical planning (breast reconstructive surgery)27
  • Prior to solid organ transplantation when vascular anatomy is needed

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
  • Suspected complications of inferior vena cava (IVC) filters
  • Follow-up for post-endovascular repair (EVAR) or open repair of abdominal aortic aneurysm (AAA)1 or abdominal extent of iliac artery aneurysms (CT preferred unless MRA/CTA is needed for procedural planning or to evaluate complex anatomy)
    • Routine, baseline study (post-op/intervention) is warranted within the first month after EVAR:
      • Repeat in 6 months if type II endoleak is seen (continue every 6 months x 24 months, then annually)
      • Repeat in 12 months if no endoleak or sac enlargement is seen
      • If neither endoleak nor AAA enlargement is seen on imaging one year after EVAR, CT is needed only if US is not feasible for annual surveillance (until year 5 as below)
  • Non-contrast CT of entire aorta (Abdomen and Pelvis) is needed every 5 years after open repair of AAA or EVAR
  • If symptomatic or imaging shows increasing or new findings related to stent graft – more frequent imaging may be needed
  • For suspected complication such as: new-onset lower extremity claudication, ischemia, or reduction in ABI after aneurysm repair

Other Indications

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)

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)29,31
  • Acute aortic dissection32
  • Takayasu’s arteritis33
  • Marfan syndrome
  • Loeys-Dietz syndrome
  • Spontaneous coronary artery dissection (SCAD)
  • Vascular Ehlers-Danlos syndrome
  • Post-operative complications34,35
  • Significant post-traumatic or post-procedural vascular complications


  1. Chaikof EL, Dalman RL, Eskandari MK, et al. The Society for Vascular Surgery practice guidelines on the care of patients with an abdominal aortic aneurysm. J Vasc Surg. Jan 2018;67(1):2-77.e2. doi:10.1016/j.jvs.2017.10.044
  2. Khosa F, Krinsky G, Macari M, Yucel EK, Berland LL. Managing incidental findings on abdominal and pelvic CT and MRI, Part 2: white paper of the ACR Incidental Findings Committee II on vascular findings. J Am Coll Radiol. Oct 2013;10(10):789-94. doi:10.1016/j.jacr.2013.05.021
  3. Kumar Y, Hooda K, Li S, Goyal P, Gupta N, Adeb M. Abdominal aortic aneurysm: pictorial review of common appearances and complications. Ann Transl Med. Jun 2017;5(12):256. doi:10.21037/atm.2017.04.32
  4. Wanhainen A, Verzini F, Van Herzeele I, et al. Editor's Choice - European Society for Vascular Surgery (ESVS) 2019 Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms. Eur J Vasc Endovasc Surg. Jan 2019;57(1):8-93. doi:10.1016/j.ejvs.2018.09.020
  5. Strate LL, Gralnek IM. ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding. Am J Gastroenterol. Apr 2016;111(4):459-74. doi:10.1038/ajg.2016.41
  6. American College of Radiology. ACR Appropriateness Criteria® Radiologic Management of Lower Gastrointestinal Tract Bleeding. American College of Radiology (ACR). Updated 2020. Accessed November 19, 2022. https://acsearch.acr.org/docs/69457/Narrative/
  7. Thakur V, Inampudi P, Pena CS. Imaging of mesenteric ischemia. Applied Radiol 2018;47(2):13-18.
  8. Harvin HJ, Verma N, Nikolaidis P, et al. ACR Appropriateness Criteria(®) Renovascular Hypertension. J Am Coll Radiol. Nov 2017;14(11s):S540-s549. doi:10.1016/j.jacr.2017.08.040
  9. American College of Radiology. ACR Appropriateness Criteria® Noncerebral Vasculitis. American College of Radiology (ACR). Updated 2021. Accessed November 20, 2022. https://acsearch.acr.org/docs/3158180/Narrative/
  10. Wanhainen A, Verzini F, Van Herzeele I, et al. Editor's Choice - European Society for Vascular Surgery (ESVS) 2019 Clinical Practice Guidelines on the Management of Abdominal Aorto-iliac Artery Aneurysms. European Journal of Vascular and Endovascular Surgery. 2019;57(1):8-93. doi:10.1016/j.ejvs.2018.09.020
  11. Baliga RR, Nienaber CA, Bossone E, et al. The role of imaging in aortic dissection and related syndromes. JACC Cardiovasc Imaging. Apr 2014;7(4):406-24. doi:10.1016/j.jcmg.2013.10.015
  12. Pode D, Caine M. Spontaneous Retroperitoneal Hemorrhage. Journal of Urology. 1992;147(2):311-318. doi:doi:10.1016/S0022-5347(17)37224-5
  13. Ioannou P, Alexakis G. Spontaneous Retroperitoneal Bleeding in a Patient with Primary Antiphospholipid Syndrome on Aspirin. Case Rep Emerg Med. 2018;2018:4397893. doi:10.1155/2018/4397893
  14. Clerc D, Grass F, Schäfer M, Denys A, Demartines N, Hübner M. Lower gastrointestinal bleeding-Computed Tomographic Angiography, Colonoscopy or both? World J Emerg Surg. 2017;12:1. doi:10.1186/s13017-016-0112-3
  15. Oakland K, Chadwick G, East JE, et al. Diagnosis and management of acute lower gastrointestinal bleeding: guidelines from the British Society of Gastroenterology. Gut. May 2019;68(5):776-789. doi:10.1136/gutjnl-2018-317807
  16. Saltzman JR. New British Guideline on Lower Gastrointestinal Bleeding. Massachusetts Medical Society. Updated March 4, 2019. Accessed November 19, 2022. https://www.jwatch.org/na48586/2019/03/04/new-british-guideline-lower-gastrointestinal-bleeding
  17. Aw-Zoretic J, Collins JD. Considerations for Imaging the Inferior Vena Cava (IVC) with/without IVC Filters. Semin Intervent Radiol. Jun 2016;33(2):109-21. doi:10.1055/s-0036-1583207
  18. Bala M, Kashuk J, Moore EE, et al. Acute mesenteric ischemia: guidelines of the World Society of Emergency Surgery. World J Emerg Surg. 2017;12:38. doi:10.1186/s13017-017-0150-5
  19. American College of Radiology. ACR Appropriateness Criteria® Imaging of Mesenteric Ischemia. American College of Radiology. Updated 2018. Accessed November 19, 2022. https://acsearch.acr.org/docs/70909/Narrative/
  20. MacCarrick G, Black JH, 3rd, Bowdin S, et al. Loeys-Dietz syndrome: a primer for diagnosis and management. Genet Med. Aug 2014;16(8):576-87. doi:10.1038/gim.2014.11
  21. Kadian-Dodov D, Gornik HL, Gu X, et al. Dissection and Aneurysm in Patients With Fibromuscular Dysplasia: Findings From the U.S. Registry for FMD. J Am Coll Cardiol. Jul 12 2016;68(2):176-85. doi:10.1016/j.jacc.2016.04.044
  22. Chu LC, Johnson PT, Dietz HC, Fishman EK. CT angiographic evaluation of genetic vascular disease: role in detection, staging, and management of complex vascular pathologic conditions. AJR Am J Roentgenol. May 2014;202(5):1120-9. doi:10.2214/ajr.13.11485
  23. Crousillat DR, Wood MJ. Spontaneous Coronary Artery Dissection: An Update for the Interventionalist. HMP Global Learning Network. Updated March 2020. Accessed November 19, 2022. https://www.hmpgloballearningnetwork.com/site/cathlab/content/spontaneous-coronary-artery-dissection-update-interventionalist
  24. Ibrahim W, Al Safran Z, Hasan H, Zeid WA. Endovascular management of may-thurner syndrome. Ann Vasc Dis. 2012;5(2):217-21. doi:10.3400/avd.cr.12.00007
  25. Wu WL, Tzeng WS, Wu RH, et al. Comprehensive MDCT evaluation of patients with suspected May-Thurner syndrome. AJR Am J Roentgenol. Nov 2012;199(5):W638-45. doi:10.2214/ajr.11.8040
  26. Hoshino Y, Machida M, Shimano Si, et al. Unilateral Leg Swelling: Differential Diagnostic Issue Other than Deep Vein Thrombosis. Journal of General and Family Medicine. 2016;17(4):311-314.
  27. American College of Radiology. ACR Appropriateness Criteria® Imaging of Deep Inferior Epigastric Arteries for Surgical Planning (Breast Reconstruction Surgery). American College of Radiology. Updated 2022. Accessed November 19, 2022. https://acsearch.acr.org/docs/3101591/Narrative/
  28. Uberoi R, Tsetis D, Shrivastava V, Morgan R, Belli AM. Standard of practice for the interventional management of isolated iliac artery aneurysms. Cardiovasc Intervent Radiol. Feb 2011;34(1):3-13. doi:10.1007/s00270-010-0055-0
  29. American College of Radiology. ACR Appropriateness Criteria® Abdominal Aortic Aneurysm: Interventional Planning and Follow-up. American College of Radiology. Updated 2017. Accessed November 19, 2022. https://acsearch.acr.org/docs/70548/Narrative/
  30. Čertík B, Třeška V, Moláček J, Šulc R. How to proceed in the case of a tumour thrombus in the inferior vena cava with renal cell carcinoma. Cor et Vasa. 2015/04/01/ 2015;57(2):e95-e100. doi:https://doi.org/10.1016/j.crvasa.2015.02.015
  31. Achenbach S, Delgado V, Hausleiter J, Schoenhagen P, Min JK, Leipsic JA. SCCT expert consensus document on computed tomography imaging before transcatheter aortic valve implantation (TAVI)/transcatheter aortic valve replacement (TAVR). J Cardiovasc Comput Tomogr. Nov-Dec 2012;6(6):366-80. doi:10.1016/j.jcct.2012.11.002
  32. Barman M. Acute aortic dissection. ESC e-J Cardio Pract. 2014;12(25):02Jul2014. doi:https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-12/Acute-aortic-dissection
  33. Keser G, Direskeneli H, Aksu K. Management of Takayasu arteritis: a systematic review. Rheumatology (Oxford). May 2014;53(5):793-801. doi:10.1093/rheumatology/ket320
  34. Bennett KM, Kent KC, Schumacher J, Greenberg CC, Scarborough JE. Targeting the most important complications in vascular surgery. J Vasc Surg. Mar 2017;65(3):793-803. doi:10.1016/j.jvs.2016.08.107
  35. Choudhury M. Postoperative management of vascular surgery patients: a brief review. Clin Surg. 2017;2:1584.
  36. Isselbacher EM, Preventza O, III JHB, et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease. Journal of the American College of Cardiology. 2022;80(24):e223-e393. doi:doi:10.1016/j.jacc.2022.08.004
  37. Abe T, Kai M, Miyoshi O, Nagaie T. Idiopathic Retroperitoneal Hematoma. Case Rep Gastroenterol. Sep 11 2010;4(3):318-322. doi:10.1159/000320590

Coding Section

Codes Number Description
CPT 74174

Computed tomographic angiography, abdomen and pelvis, 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 nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies, and accredited national guidelines.

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