78580

Pulmonary Perfusion Imaging, Particulate

CPT code 78580 describes a nuclear medicine procedure known as pulmonary perfusion imaging, which utilizes particulate radiopharmaceuticals to evaluate blood flow throughout the lungs. This diagnostic study is most frequently employed in the diagnostic workup for pulmonary embolism (PE), a potentially life-threatening condition where a blood clot obstructs a pulmonary artery. The technical execution involves the intravenous administration of Technetium-99m labeled Macroaggregated Albumin (Tc-99m MAA). These particles, typically ranging from 10 to 90 micrometers in size, are slightly larger than the pulmonary capillaries. Upon injection, they travel through the right side of the heart and into the pulmonary arterial system, where they become physically trapped in a small fraction (less than 0.1 percent) of the pulmonary capillary bed. The concentration of these particles in any given region of the lung is directly proportional to the regional pulmonary blood flow at the moment of injection. Once the radiopharmaceutical is distributed, the patient is imaged using a gamma camera. The camera detects the gamma rays emitted by the Technetium-99m, producing images that show the distribution of perfusion. A normal scan shows uniform distribution of the tracer throughout both lung fields. In contrast, a scan showing 'cold spots' or areas of absent uptake indicates a perfusion defect. While perfusion imaging is highly sensitive, it is non-specific; therefore, it is often interpreted alongside a chest X-ray or a ventilation scan to differentiate between vascular issues like PE and parenchymal lung diseases such as pneumonia or chronic obstructive pulmonary disease (COPD). The procedure is safe, with the MAA particles eventually breaking down and being cleared by the liver and spleen over several hours.

Clinical Indications

  • Suspected acute pulmonary embolism
  • Evaluation of regional pulmonary perfusion
  • Pre-operative assessment prior to lung resection or reduction surgery
  • Monitoring of pulmonary hypertension
  • Assessment of congenital heart disease with right-to-left shunting
  • Evaluation of pulmonary vasculitis

Procedure Steps

  1. Verification of patient identity and screening for pregnancy or breastfeeding status.
  2. Establishment of intravenous (IV) access.
  3. Positioning the patient in a supine position to ensure uniform particle distribution and minimize gravitational influence.
  4. Intravenous injection of Technetium-99m Macroaggregated Albumin (Tc-99m MAA) while the patient performs normal tidal breathing.
  5. Positioning the patient under a gamma camera (scintillation camera).
  6. Acquisition of multiple planar images of the chest in several projections including Anterior, Posterior, Right Lateral, Left Lateral, Right Posterior Oblique, and Left Posterior Oblique.
  7. Processing and quantitative analysis of images by a nuclear medicine technologist.
  8. Final interpretation of the perfusion patterns by a radiologist or nuclear medicine physician.

Coding Guidelines

  • Code 78580 is used specifically for the perfusion portion of a lung scan; it should not be used if a ventilation study is also performed during the same session.
  • For a combined ventilation and perfusion study, refer to code 78582.
  • The radiopharmaceutical (e.g., A9540 for Tc-99m MAA) is typically reported separately using the appropriate HCPCS Level II code.
  • If the procedure is performed as a SPECT study instead of planar imaging, refer to code 78597 or 78598.
  • Use modifier 26 to report the professional component only when the physician does not own the equipment.
  • Use modifier TC to report the technical component only.
  • Do not report 78580 in conjunction with codes for quantitative differential pulmonary perfusion (78591) unless distinct and medically necessary.

Associated ICD-10 Codes