73700

Computed tomography, lower extremity; without contrast material

Computed tomography (CT) of a lower extremity is a non-invasive diagnostic imaging procedure that uses X-rays and computer processing to create detailed cross-sectional images of bones, soft tissues, and blood vessels in the lower limb (e.g., hip, femur, knee, tibia, fibula, ankle, foot). This specific code, 73700, indicates that the study was performed without the administration of intravenous (IV) contrast material. The procedure helps in evaluating fractures, tumors, infections, degenerative changes, and other pathologies where detailed bone visualization is critical or where contrast is contraindicated or not necessary.

Clinical Indications

  • Evaluation of acute or chronic fractures, including complex or intra-articular fractures, and assessment of fracture healing or non-union.
  • Detection and characterization of bone tumors (benign or malignant) or other bone lesions, including assessment of their extent and involvement.
  • Diagnosis and assessment of osteomyelitis or other bone infections, especially in cases where radiography is inconclusive or MRI is contraindicated.
  • Evaluation of degenerative joint disease, arthropathy, or other joint abnormalities, particularly for pre-operative planning or post-operative assessment.
  • Localization and identification of foreign bodies within the soft tissues or bone of the lower extremity.
  • Assessment of congenital malformations or developmental abnormalities of the lower limb skeleton.
  • Identification of dislocations or subluxations, especially when plain radiographs are insufficient.
  • Guidance for biopsy or other interventional procedures within the lower extremity.

Procedure Steps

  1. Patient is positioned supine on the CT scanner table, with the lower extremity of interest carefully immobilized and centered within the scan field.
  2. A scout image (topogram) is acquired to define the precise anatomical area to be scanned.
  3. CT images are acquired without the administration of intravenous contrast material, covering the specified region (e.g., hip, femur, knee, tibia/fibula, ankle, or foot).
  4. Raw data is processed and reconstructed into axial, coronal, and sagittal planes, and often 3D reconstructions are performed for better visualization of complex anatomy.
  5. Images are reviewed by a radiologist who generates a diagnostic report detailing findings and impressions.

Coding Guidelines

  • Code 73700 specifically describes a CT scan of the lower extremity performed without any intravenous contrast material. If oral, rectal, or vaginal contrast is used without IV contrast, it is still reported with 73700.
  • If contrast material is administered intravenously during the same session, code 73701 (with contrast) or 73702 (without followed by with contrast) should be used, not 73700.
  • Documentation must clearly state the reason for the scan and confirm that no intravenous contrast was administered.
  • This code is typically performed in a hospital outpatient, inpatient, or freestanding imaging center setting.
  • Medical necessity must be clearly documented in the patient's medical record to support the procedure.
  • Do not report separately for services that are components of a more comprehensive CT study of the lower extremity.
  • This code has a global period of 'XXX' (global concept does not apply), meaning no follow-up care is included in the payment for the procedure itself.

Associated ICD-10 Codes