CPT Code 78431 | Description & Clinical Information
CPT 78431 describes a nuclear imaging test, specifically a PET myocardial imaging scan with CT transmission scan, that is used to reveal blood flow to and from the heart (perfusion), and includes ejection fraction and ventricular wall motion studies if performed, for multiple studies at rest and with pharmacologic or exercise stress testing.
Official Description
The CPT book defines CPT code 78431 as: “Myocardial imaging, positron emission tomography (PET), perfusion study (including ventricular wall motion[s] and/or ejection fraction[s], when performed); multiple studies at rest and stress (exercise or pharmacologic), with concurrently acquired computed tomography transmission scan”.
Clinical Information
The procedure described by CPT code 78431 is a diagnostic nuclear medicine imaging technique called myocardial imaging by positron emission tomography (PET) scan. This procedure produces three-dimensional images that show how the heart muscle is working while using computed tomography (CT) transmission scanning and PET imaging. The concurrent use of CT and PET imaging helps the provider determine whether the activity detected is physiologic or pathologic.
During the procedure, the provider injects a radioactive tracer into the patient’s bloodstream. This radionuclide is created by applying a radioactive atom to a biological compound or drug. The radionuclide travels in the bloodstream and eventually reaches the heart. If a pharmacologic stress test is needed, the provider may also inject another drug such as Lexiscan (regadenoson) to stress the heart.
Once the radionuclide reaches the target area in the heart, it breaks down into tiny positively charged particles called positrons, emitting gamma rays. The PET and CT scanners detect these gamma rays given off by the radioactive substance. The computer then processes the emitted data to produce multidimensional images of the distribution of the drug or biological compound throughout the heart muscle.
Generally, after image acquisition at rest, the provider will perform a stress test. If the patient can exercise, the provider will have them do so. However, if the patient is not able to exercise, the provider will have known this before the study began and injected a drug for a pharmacologic nuclear stress test.
The provider may also evaluate ventricular wall motion and the ejection fraction. The ejection fraction is the percentage of blood pumped out of a filled ventricle with each heartbeat. These evaluations help the provider to better understand the function of the heart muscle.
The CT and PET data are fused, and the images are presented to the interpreter on a monitor. The images can be viewed as CT data, PET data, and superimposed CT/PET data. This data helps the provider evaluate perfusion (blood flow) to and from the heart. Using this information, the provider can draw inferences about whether the heart muscle is functioning normally or not.
Concurrent imaging, which combines CT and PET scanning, also shortens imaging time. Moreover, it allows for precise localization of radionuclide activity, attenuation correction, spatial registration and alignment, and motion, which translates into more accurate scans.
In summary, the myocardial imaging by PET scan using CPT code 78431 is a highly effective way to evaluate the heart muscle’s function. It involves the injection of a radioactive tracer into the bloodstream, followed by imaging scans using CT and PET technologies. The data gathered is presented in multidimensional images to the provider, who can then evaluate perfusion to and from the heart, as well as its function overall. This procedure is a valuable diagnostic tool and is essential in the evaluation and management of cardiac diseases, including coronary artery disease and heart failure.
Return to all the CPT codes for diagnostic nuclear medicine procedures on the cardiovascular system.
