Cardiology Coding Alert

Coding for positron emission tomography (PET) scans depends mainly on whether the scan is a single or multiple test and whether it is conducted while the patient is at rest or under stress, through either exercise or pharmaceutical inducement.

Although PET scans may be new to many coders, these nuclear diagnostic tests pose some of the same coding issues as the more commonly used single-photon emission computerized tomography (SPECT) scans.

In general, a PET scan is a noninvasive diagnostic imaging procedure that assesses the level of metabolic activity and perfusion in an organ system, including the circulatory system. During a PET scan, the patient receives a radiopharmaceutical injection - typically rubidium-82 for cardiology imaging - through a previously placed catheter and is scanned in a cyclotron equipped with a gamma camera.

Larger cardiology practices use PET scans to measure myocardial blood flow or perfusion and to assess the extent of coronary artery disease (CAD) after inconclusive SPECT scans.

At this point, cardiologists routinely use PET scans to assess the viability of heart muscle, says Marko Yakovlevitch, MD, FACP, FACC, a cardiologist in private practice in Seattle. PET scanning is considered the gold standard for assessing whether that heart muscle is still alive and would recover if you supplied it with more blood, he observes.

You should use 78459 (Myocardial imaging, positron emission tomography [PET], metabolic evaluation) "to report PET imaging for myocardial viability (metabolic evaluation) only," according to the American College of Cardiology's Guide to CPT 2002.

When the cardiologist performs a single study scan, you should report 78491 (Myocardial imaging, positron emission tomography [PET], perfusion; single study at rest or stress).

If the physician does multiple studies either at rest or with stress, the procedure should be coded 78492 (... multiple studies at rest and/or stress).

Typically, cardiac physicians perform PET scans on patients who have CAD with left ventricular dysfunction, says Melody Mulaik, MSHS, CPC, RCC, a coding specialist with Atlanta-based Coding Strategies Inc.

For example, a patient may have ischemic heart disease. Consequently, you would use codes in the 410-414 range to indicate location and intensity of the lack of blood flow to a particular region of the heart.

Usually, the physician records a transmission scan immediately prior to the study to improve the quality of the reconstructed data. You should not bill separately for that, however, because it's considered an inherent part of the PET scan, Mulaik says.

If the cardiologist performs a perfusion evaluation in addition to the metabolic evaluation, you would use 78492, Mulaik says.

As of Oct. 1, Medicare will cover myocardial perfusion studies using PET scanning with rubidium-82 on FDA-approved equipment. CMS specifies that scans can be done only on patients with known or suspected CAD following a SPECT study that is inconclusive.

For instance, a patient with acute coronary occlusion without myocardial infarction (411.81) or coronary atherosclerosis (414.0x) may need a PET scan if a prior transmission scan fails to show enough information about the health of myocardial cells in a region where there is potential damage to heart muscle.

You should use G0230 when the cardiologist uses a PET scan to assess myocardial viability in patients when there is suspected compromise of ventricular function to determine appropriateness of revascularization, Mulaik emphasizes.

Cardiology coders should use PET scan codes G0030-G0047 to report the service depending on the type of diagnostic test that preceded a perfusion scan. Diagnostic tests in this series of G codes include SPECT scans, coronary angiography, echocardiograms and nuclear ventriculograms.

For example, you should use G0046 "if the PET perfusion study is performed on a patient with suspected coronary artery disease revealed by a positive exercise treadmill test," according to the Guide to CPT 2002.

CMS in particular wants to make sure that it is paying for a diagnostic study that could help prevent an invasive procedure, so physicians must document the reasons for the test, Mulaik says.

Indeed, CMS considers the use of PET reasonable and necessary if it replaces one or more types of imaging studies. "Payers don't want PET to be duplicative of something else that's being done; the purpose of the scan for CMS is that we're minimizing what we have to do to the patient," Mulaik observes.

For example, if the study is indicated for hibernation, the cardiologist should document that the patient has an area of severe hypokinesis or akinesis and is being considered for revascularization, Yakovlevitch says. In this instance, payers will want to see that the physician is performing the study to evaluate for hibernating myocardium.

In essence, there must be a very specific reason for doing the PET scan if carriers are going to reimburse. The documentation should reflect that the diagnostic test distinguished between dysfunctional but viable myocardial tissue and scar tissue to affect management decisions, Mulaik says.

Mulaik suggests that coders consult local carriers' medical review policies to determine the extent of coverage for PET scans and the diagnostic codes required

Editor's note: To read the CMS program memo, go to http://cms.hhs.gov/manuals/pm_trans/AB01168.pdf.