74176

Computed Tomography, Abdomen and Pelvis; Without Contrast Material

Computed Tomography (CT) of the abdomen and pelvis performed without the administration of intravenous (IV) contrast material is a sophisticated diagnostic imaging study. This procedure utilizes a rotating X-ray tube and multiple detectors to capture high-resolution, cross-sectional images of the internal organs, skeletal structures, and soft tissues ranging from the diaphragm to the pubic symphysis. During the procedure, the patient lies supine on a motorized gantry that moves through a circular scanner. The raw data captured is processed via advanced computer algorithms to reconstruct images in axial, coronal, and sagittal planes, allowing for a comprehensive three-dimensional evaluation. Because this specific study is performed without IV contrast, it is the gold standard for identifying high-density materials such as renal or ureteral calculi (kidney stones), which might otherwise be obscured by the brightness of contrast media. It is also frequently utilized for patients with contraindications to iodinated contrast agents, such as those with significant renal insufficiency, a history of severe contrast allergies, or thyroid storm. The non-contrast technique is effective for evaluating gross abnormalities, bowel obstructions, large masses, and abdominal aortic aneurysms, and for providing a baseline in trauma settings where immediate bone and soft tissue assessment is required. Although it provides less vascular detail than enhanced studies, its speed and safety profile make it a critical tool in emergency and routine diagnostic protocols.

Clinical Indications

  • Suspected nephrolithiasis or urolithiasis (kidney stones)
  • Acute abdominal or pelvic pain of unknown etiology
  • Contraindication to intravenous contrast (e.g., renal failure, allergy)
  • Evaluation of abdominal aortic aneurysm (AAA)
  • Assessment of bowel obstruction or perforation
  • Monitoring of known abdominal or pelvic masses
  • Follow-up of previously identified retroperitoneal lymphadenopathy
  • Initial evaluation of blunt or penetrating abdominal trauma
  • Screening for hernias (incisional, inguinal, or umbilical)
  • Post-operative evaluation of surgical clips or hardware

Procedure Steps

  1. Patient identification and verification of the clinical indication.
  2. Removal of all radiopaque objects such as jewelry, belts, or clothing with metal zippers.
  3. Positioning the patient in a supine position on the CT table, typically with arms raised above the head.
  4. Instruction of the patient regarding breath-holding techniques to minimize motion artifact.
  5. Performance of an initial scout image (topogram) to determine the anatomical boundaries for the scan.
  6. Setting the technical parameters including kilovoltage (kVp), milliamperage (mA), and slice thickness.
  7. Execution of the spiral/helical scan sequence from the level of the diaphragm through the pubic symphysis.
  8. Review of raw data to ensure adequate coverage and image quality.
  9. Multiplanar reconstruction (MPR) of images into axial, sagittal, and coronal views by the technologist.
  10. Transmission of reconstructed images to the Picture Archiving and Communication System (PACS) for radiologist interpretation.

Coding Guidelines

  • Use 74176 for a combined CT of the abdomen and pelvis performed without IV contrast during a single session.
  • Do not report 74176 in conjunction with 74150 (CT Abdomen) or 72192 (CT Pelvis) for the same encounter.
  • The phrase 'without contrast' refers to intravenous contrast; the administration of oral or rectal contrast does not change the code to a 'with contrast' study.
  • If the study is performed without contrast followed by contrast, use code 74178 instead.
  • Append modifier -26 if only the professional component (radiologist's interpretation) is being billed.
  • Append modifier -TC if only the technical component (equipment and staff) is being billed.
  • If the procedure is performed in a hospital setting, the facility bills the technical component and the physician bills the professional component.

Associated ICD-10 Codes