Radiology Coding Alert

Few areas of radiology coding require greater attention to detail than positron emission tomography (PET) imaging, a noninvasive procedure using radiopharmaceuticals to assess the perfusion or metabolic activity in various organ systems. PET is considered a state-of-the-art diagnostic tool and is clinically effective in the management of cancer and cardiac and neurological diseases.

To date, however, it has been regarded as investigational, and both Medicare carriers and private payers have strict guidelines for reporting these services.

It is a very challenging area of radiology coding, notes Stacie L. Buck, RHIA, internal auditor for U.S. Diagnostic Inc., a corporation based in West Palm Beach, Fla., that owns and operates diagnostic imaging centers in several states.

Besides those factors that universally affect other areas of coding (e.g., medical necessity, appropriate diagnoses and frequency considerations), PET imaging also demands that nuclear radiologists and coders take into account additional elements. These include the anatomical site being scanned, previous diagnostic assessments performed, and the type of radiopharmaceutical being injected. In addition, two sets of codes for reporting PET imaging exist CPT Codes to be used with private payers and HCPCS Codes to be used with Medicare beneficiaries.

Finally, coders must be aware that Medicare has a set of modifiers unique to PET imaging codes. Claims submitted without these alpha modifiers will be summarily denied.

Its tempting to try to generalize coding conventions, Buck says. But that would be disastrous with PET imaging. Every study is governed by a different set of guidelines. Coders must be familiar with all the variables and know how they apply to each circumstance. Without this understanding, getting paid is virtually impossible.

Most experts also advise coders to work closely with their radiologist, since codes describing PET demand a thorough understanding of clinical considerations as well.

Specific Applications Covered Incrementally

HCFA initially approved coverage for one application of PET scans in March 1995 imaging of the perfusion of the heart and has incrementally approved other, narrowly defined uses during the ensuing six years. These include initial staging of lung cancer, recurrence of colorectal cancer, staging and characterization of lymphoma, and recurrence of melanoma. Coders should check local medical review policies to determine the specific requirements governing each study.

This list promises to grow rapidly in upcoming months and years, with HCFAs Dec. 15, 2000, announcement that it intends to expand Medicare coverage of PET imaging. Although no effective date or coding guidelines have been officially announced, the policy will expand coverage in the four previously approved cancers (lung, colorectal, lymphoma and melanoma) and add two sites (esophageal, and head and neck). HCFA says coverage of dedicated full circular ring scanners and some partial ring systems will include all clinically appropriate uses for these six types of cancer. Among the cancers still excluded from this list are those affecting the brain and thyroid. In addition, HCFA will initiate coverage for patients with refractory epilepsy or who may be candidates for coronary revascularization.

Calling this policy change a science-based coverage decision, HCFA noted that approval of these new uses of PET may allow some Medicare beneficiaries to avoid invasive procedures. In addition, it may also give beneficiaries and their physicians information that will increase confidence in the management of the disease.

Other PET applications under consideration, but not approved to date, include myocardial viability, dementia and breast cancer.

CPT Provides Six Codes for PET Imaging

Now, CPT offers six codes for reporting PET scans. These codes may not be assigned for Medicare beneficiaries and may or may not be accepted by private payers. Buck advises radiology coding professionals to work closely with appropriate medical directors to determine specific policies.

Available codes include:

78459 myocardial imaging, positron emission tomography [PET], metabolic evaluation;

78491 myocardial imaging, positron emission tomography (PET), perfusion; single study at rest or stress; and

78492 myocardial imaging, positron emission tomography (PET), perfusion; multiple studies at rest and/or stress.

The previous three codes describe PET myocardial imaging, which measures myocardial viability and is typically performed on patients with a clinical question of coronary artery disease with and/or without left ventricular dysfunction.

78608 brain imaging, positron emission tomography (PET); metabolic evaluation; and

78609 brain imaging, positron emission tomography (PET); perfusion evaluation.

The previous two codes describe imaging on patients with suspected cerebrovascular conditions, or the presence of primary or metastatic tumors or lesions.

78810 tumor imaging, positron emission tomography (PET), metabolic evaluation.

The previous code is used for tumor localization, to differentiate between benign and malignant disease, to determine the extent and progression of malignant disease, and to evaluate the response of a known tumor to therapy.

These do not correlate directly with the codes that may be reported for Medicare. There are no codes for brain imaging, for instance, because HCFA does not recognize this application as billable. Nor does Medicare allow PET scans for general tumor imaging only for specific sites.

Medicare Coverage for Heart Perfusion Imaging

The most extensive list of HCPCS codes for reporting PET scans describes myocardial perfusion imaging, according to April Brazinsky, CCS, coding specialist for the Community Hospital of the Monterey Peninsula in California. This series of codes begins with G0030 and continues through G0047, she says. A wide range of imaging scenarios is covered, including single and multiple studies conducted in various combinations of rest and stress. The individual codes also reflect PET imaging performed after other diagnostic studies, like coronary angiography or an EKG.

These noninvasive scans are used to diagnose and manage the treatment of patients with known or suspected coronary artery disease, she adds. However, they are not billable when used for routine screening of patients, even if that patient exhibits a number of significant risk factors. These codes may be reported if the scans have been used in place of, but not in addition to, SPECT unless the previous SPECT study was inconclusive. In that instance, coders would report G0032, G0033, G0034 or G0035, which specifically describe PET following SPECT.

HCFA also notes that these codes may be reported only when the radiopharmaceutical rubidium 82 (Rb 82) is used.

Coverage of Staging of Lung Cancers

In 1998, Medicare began covering PET imaging for the characterization of suspected solitary pulmonary nodules (SPNs) to determine the likelihood of malignancy. Use of these codes, Buck points out, is contingent on the use of the radiopharmaceutical fluorodeoxyglucose (FDG).

In addition, Medicare requires that PET be performed only after evidence of an initial primary lung tumor has been found. Most often, she says, this occurs following computed tomography (CT). Medicare says that, to report PET for SPNs, we must be able to demonstrate that a CT or similar diagnostic study was performed and that it indicated a possibly malignant lesion. It also notes that the suspected lesion cannot exceed four centimeters in diameter. If these conditions are not met, the service is not billable.

The relevant HCPCS code is G0125 (PET lung imaging of solitary pulmonary nodules, using 2-[fluorine-18]-fluoro-2-deoxy-d-glucose [FDG], following CT [71250/71260 or 71270]).

Brazinsky notes that, in most instances, Medicare will not pay for tissue sampling procedures following a negative PET scan. Since a negative PET indicates that the lesion is most likely not malignant, Medicare would not cover a subsequent biopsy or similar procedure.

However, there are occasions when a followup biopsy may be indicated (e.g., to identify an infection as opposed to granulomatous disease, or to assess certain nonmalignant processes). If a biopsy is performed following a PET scan that does not reveal malignancy, the medical record should demonstrate the clinical reasons for the biopsy. Simply confirming the PET scan results will most likely result in nonpayment, but uncovering further diagnostic information about the etiology of the nonmalignant lesion is appropriate in certain clinical circumstances.

Likewise, Medicare coverage for PET imaging of non-small cell lung carcinoma (NSCLC) is equally restrictive. It may be reported only if it is used during the initial staging of metastatic NSCLC in the thoracic lymph nodes. We can only report these services in patients who have a confirmed primary lung tumor, but where we have not yet identified the extent of the disease, explains Buck.

Medicare policy notes that PET may be used to determine the stage of the disease in order to plan future treatment but that multiple staging using PET is not covered since that would constitute monitoring the disease, rather than simply staging it. In addition, radiologists reporting this service must also provide evidence (i.e., surgical pathology report) that a primary cancerous lung tumor has been found. When these claims are submitted Medicare also requires that a concurrent thoracic CT be performed, along with a lymph node biopsy to determine whether the patient is a candidate for surgery.

These services are described in code G0126 (PET lung imaging of solitary pulmonary nodules, using 2-[fluorine-18]-fluoro-2-deoxy-d-glucose [FDG], following CT [71250/71260 or 71270]; initial staging of pathologically diagnosed non-small cell lung cancer).

Medicare does not allow subsequent lymph node biopsies when both CT and PET were negative. However, this biopsy may be reported in all other circumstances (e.g., positive CT and positive PET, positive CT and negative PET).

Coverage in Patients With Colorectal Tumors

HCFA introduced G0163 (positron emission tomography [PET], whole body, for recurrence of colorectal metastatic cancer) in 1999. This code may be assigned when PET is conducted to determine the location of recurrent colorectal tumors. These tumors are indicated by rising levels of the carcinoembryonic antigen (CEA).

When PET is performed in this situation, explains Brazinsky, it is to determine whether or not surgery needs to be done to remove the tumors. As with lung cancer, this code may be reported only when evidence of previous colorectal cancer is submitted.

She adds that gallium scans, another diagnostic tool often used to locate recurrent colorectal cancer, will not be covered if performed by the same facility within a specified number of days as a PET scan.

Coverage for Staging Lymphomas

PET imaging as an alternative to gallium scans is covered when used for staging both Hodgkins and non-Hodgkins lymphomas. They are reported using G0164 (positron emission tomography [PET], whole body, for staging and characterization of lymphoma). The radiopharmaceutical FDG is used.

As with NSCLC, Buck says, PET may be used only for staging and restaging these diseases to determine the progress and extent of the disease in order to plan future management for the patient. In addition, PET will not be covered if performed within a specified number of days as a gallium scan at the same facility. Nor will PET be allowed for restaging if previous staging studies were conducted fewer than 50 days.

Coverage for Melanoma

Buck says Medicare covers PET imaging only to evaluate a recurrent episode of melanoma to determine whether surgery is indicated. In those instances, it would be reported with G0165 (positron emission tomography [PET], whole body, for recurrence of melanoma or melanoma metastatic cancer).

As with other PET imaging codes, G0165 is covered only when FDG is used, and will be denied if a gallium scan was performed within a specified number of days by the same facility. Whole-body PET scans will not be reimbursed more frequently than once every 12 months.

Unique Modifiers Indicate Scan Results

Medicare has also implemented a distinct set of alpha-character modifiers to be appended to PET codes. These two-digit modifier sets are intended to provide HCFA with information about the outcome of the PET study, as well as the outcome of previous tests.

The modifier sets include:

N negative

E equivocal

P positive, but not suggestive of extensive ischemia or not suggestive of malignant SPN

S positive and suggestive of extensive ischemia (greater than 20 percent of the left ventricle) or malignant SPN.

These modifiers may be used in any combination to describe the results of the diagnostic studies. The first character should describe the outcome of the PET scan, while the second should describe the outcome of the previous study.

For instance, a 58-year-old male patient presents for a PET scan after an EKG was performed to ascertain the presence of coronary artery disease. The EKG produced questionable findings, while the PET was positive but did not suggest ischemia. Correct coding with the alpha modifiers would be G0044-PE. The P indicates the result of the PET, while the E reflects the equivocal nature of the prior EKG.