74175

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

Computed tomographic angiography (CTA) of the abdomen (CPT code 74175) is an advanced, non-invasive diagnostic imaging modality explicitly designed to evaluate the complex vascular anatomy and pathology within the abdominal cavity. This procedure requires the intravascular administration of iodinated contrast material to heavily opacify the blood vessels, allowing for high-resolution, multiplanar visualization of critical structures including the abdominal aorta, renal arteries, celiac trunk, superior and inferior mesenteric arteries, and iliac vessels. The descriptor for CPT 74175 inherently includes any preliminary non-contrast imaging performed prior to the contrast injection. A non-contrast phase is frequently utilized by radiologists to identify baseline calcifications, intramural hematomas, or active hemorrhage before they are obscured by contrast media. Following contrast administration, imaging is timed precisely using sophisticated techniques such as bolus tracking or a test bolus. This ensures the scanner captures the target vessels during peak arterial or venous enhancement. What distinctly separates a CTA from a standard contrast-enhanced CT of the abdomen is the use of specialized acquisition parameters optimized purely for vascular opacification, coupled with mandatory complex image postprocessing. This postprocessing involves computationally demanding 3D rendering techniques such as maximum intensity projection (MIP), multiplanar reconstruction (MPR), and volume rendering (VR) which are essential for both accurate diagnostic interpretation and detailed surgical planning. Radiologists rely on these advanced reconstructions to accurately measure vessel diameters, assess the hemodynamic significance of stenoses, identify aneurysmal dilation or dissection flaps, and evaluate the functional patency of endovascular stents or surgical bypass grafts. Because CPT code 74175 comprehensively bundles both the technical acquisition of these complex image sets and the physician cognitive work in post-processing the data, separate reporting of 3D rendering codes is strictly prohibited. Clinical scenarios heavily relying on this procedure include the preoperative planning for abdominal aortic aneurysms (AAA), emergent evaluation of suspected aortic dissection or acute mesenteric ischemia, diagnostic workup for renal artery stenosis in cases of secondary hypertension, and the precise vascular mapping required prior to organ transplantation or complex abdominal surgeries. This exhaustive examination provides critical intelligence that seamlessly guides both minimally invasive endovascular interventions and definitive open surgical management.

Clinical Indications

  • Abdominal aortic aneurysm (AAA) screening, measurement, or preoperative planning
  • Suspected acute or chronic abdominal aortic dissection
  • Acute or chronic mesenteric ischemia
  • Renal artery stenosis in patients with refractory or secondary hypertension
  • Preoperative vascular mapping for abdominal organ transplantation (e.g., kidney, liver)
  • Evaluation of abdominal vascular malformations or fistulas
  • Assessment of endovascular stent graft patency and endoleak detection
  • Traumatic injury to abdominal blood vessels
  • Unexplained gastrointestinal bleeding of suspected vascular origin

Procedure Steps

  1. Review patient medical history, verify contrast allergy status, and evaluate baseline renal function (e.g., eGFR).
  2. Position the patient supine on the CT scanner table with arms extended above the head to minimize beam-hardening artifacts.
  3. Acquire an initial scout image (topogram) to define the anatomical scanning range from the diaphragm down to the aortic bifurcation or common iliac arteries.
  4. Perform an optional unenhanced (non-contrast) CT scan of the abdomen to assess for baseline calcifications or acute hematoma, if clinically indicated.
  5. Establish adequate intravenous access (typically an 18- or 20-gauge catheter in the antecubital vein) and connect to a dual-head power injector.
  6. Administer iodinated contrast material via the power injector at a high flow rate (e.g., 4 to 5 mL per second), immediately followed by a saline chaser.
  7. Utilize bolus tracking software or a timing bolus with a region of interest (ROI) placed in the descending aorta to trigger image acquisition during peak arterial enhancement.
  8. Rapidly acquire thin-slice axial CT images through the entire targeted abdominal volume during the arterial phase.
  9. Transfer the acquired volumetric data to an independent, dedicated 3D workstation for required image post-processing.
  10. Perform complex image post-processing including multiplanar reconstructions (MPR), maximum intensity projections (MIP), and 3D volume rendering (VR).
  11. Radiologist interprets both the axial source images and the 3D reconstructions, culminating in a comprehensive diagnostic report detailing vascular pathology.

Coding Guidelines

  • CPT code 74175 inherently includes all required 3D image post-processing; therefore, do not report 76376 or 76377 (3D rendering) concurrently.
  • The procedure includes any non-contrast images obtained prior to contrast administration; do not separately report CPT 74150 (CT abdomen without contrast).
  • Do not report CPT 74175 in conjunction with CPT 74160 (CT abdomen with contrast) or 74170 (CT abdomen without and with contrast) for the same anatomic region during the same session.
  • If performing a combined CTA of the abdomen AND the pelvis, report the combination code CPT 74174 instead of reporting 74175 and 72191 separately.
  • The contrast material must be administered intravascularly to qualify as a Computed Tomographic Angiography (CTA); oral or rectal contrast alone does not meet the criteria for this code.
  • Documentation must explicitly state that 3D post-processing was performed to support the use of a CTA code versus a standard CT code.

Associated ICD-10 Codes