91200

Liver elastography, percutaneous

CPT code 91200 describes a non-invasive diagnostic procedure used to assess liver tissue stiffness, which is a primary surrogate marker for hepatic fibrosis and cirrhosis. The procedure is performed percutaneously, typically using ultrasound-based technologies such as Vibration-Controlled Transient Elastography (VCTE) or Shear Wave Elastography (SWE). During the examination, a clinician or technician places a specialized probe against the patient's skin, usually in the intercostal spaces over the right lobe of the liver. The device generates a mechanical vibration or an acoustic radiation force impulse (ARFI) that creates a shear wave within the liver parenchyma. The velocity of this shear wave is measured as it travels through the tissue; because waves travel faster through denser, more rigid structures, higher velocities correlate with increased liver stiffness. The resulting data is quantified, often in kilopascals (kPa) or meters per second (m/s), providing an objective score that correlates with various METAVIR fibrosis stages (F0 to F4). This procedure is highly valued because it provides a representative sample of liver tissue that is significantly larger than a traditional needle biopsy core, without the associated risks of hemorrhage, pain, or organ injury. The 91200 service includes the technical component of data acquisition, the use of real-time image guidance to locate an appropriate acoustic window, and the professional interpretation of the stiffness measurements in the clinical context of the patient's underlying liver condition. It is frequently used for both the initial staging of liver disease and the longitudinal monitoring of treatment response in chronic liver conditions.

Clinical Indications

  • Chronic Hepatitis C infection for staging of fibrosis
  • Chronic Hepatitis B infection monitoring
  • Non-alcoholic Fatty Liver Disease (NAFLD)
  • Non-alcoholic Steatohepatitis (NASH)
  • Alcoholic Liver Disease
  • Primary Biliary Cholangitis (PBC)
  • Primary Sclerosing Cholangitis (PSC)
  • Autoimmune Hepatitis
  • Hemochromatosis and iron overload disorders
  • Wilson's Disease
  • Drug-induced liver injury (DILI) monitoring
  • Evaluation of suspected cirrhosis in patients with portal hypertension

Procedure Steps

  1. Verify patient identity and ensure the patient has fasted for at least 3 to 4 hours to minimize postprandial blood flow interference.
  2. Position the patient in a supine or slight left lateral decubitus position with the right arm fully abducted to open the intercostal spaces.
  3. Apply ultrasound gel to the skin over the right lobe of the liver, typically at the mid-axillary line.
  4. Use real-time image guidance or localized ultrasound pulses to identify an appropriate area of liver parenchyma, avoiding large blood vessels, the gallbladder, and rib shadows.
  5. Apply the elastography transducer probe perpendicular to the skin surface with appropriate pressure.
  6. Trigger the device to emit the shear wave pulse and record the resulting tissue displacement or wave velocity.
  7. Perform a minimum of 10 valid acquisitions to ensure statistical reliability of the median stiffness measurement.
  8. Calculate the median stiffness value and the Interquartile Range (IQR); an IQR/median ratio of less than 30% is generally required for a reliable study.
  9. Review the calculated scores and generate a formal report correlating the findings with known fibrosis staging scales.

Coding Guidelines

  • CPT 91200 includes image guidance (e.g., ultrasound) when performed to identify the measurement site; do not report 76700 or 76705 separately for this purpose.
  • This code represents a global service; if only the interpretation is performed, use modifier 26. If only the technical component is performed, use modifier TC.
  • Do not report 91200 in conjunction with MR elastography (76391), as that is a different modality (MRI-based).
  • If liver elastography is performed as part of a more comprehensive ultrasound of the abdomen, check NCCI edits; generally, the more specific procedure (91200) is used if the primary intent is fibrosis staging.
  • Only one unit of 91200 should be reported per encounter, regardless of the number of pulses or measurements taken to reach the median score.

Associated ICD-10 Codes