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Cardiac positron emission tomography (PET) scanning is used in two key clinical situations: (1) myocardial perfusion scanning as a technique to identify perfusion defects, which in turn reflect coronary artery disease (CAD); and (2) assessment of myocardial viability in patients with left ventricular (LV) dysfunction as a technique to determine candidacy for a revascularization procedure. Cardiac PET also is being studied in the measurement of myocardial blood flow and blood flow reserve and for evaluation of coronary artery inflammation.
Positron emission tomography (PET) scans use positron-emitting radionuclide tracers, which simultaneously emit 2 high energy photons in opposite directions. These photons can be simultaneously detected (referred to as coincidence detection) by a PET scanner, consisting of multiple stationary detectors that encircle the thorax. Compared to single-photon emission computed tomography scans, coincidence detection offers greater spatial resolution.
A variety of radionuclide tracers are used for PET scanning, including fluorine-18, rubidium-82, oxygen-15, nitrogen-13, and carbon-11. Most tracers have a short half-life and must be manufactured with an on-site cyclotron. Rubidium-82 is produced by a strontium-82/rubidium-82 generator. The half-life of fluorine-18 is long enough that it can be manufactured commercially at offsite locations and shipped to imaging centers. Radionuclides may be coupled with a variety of physiologically active molecules, such as oxygen, water, or ammonia. Fluorine-18 is often coupled with fluorodeoxyglucose (FDG) to detect glucose metabolism, which in turn reflects metabolic activity, and thus viability, of the target tissue. Tracers that target the mitochondrial complex also are being developed.
Cardiac PET scanning focuses on 2 distinct clinical situations:
This policy focuses on the cardiac applications of PET scanning.
POLICYI. For Myocardial Perfusion Studies:
Cardiac PET scanning may be considered medically necessary to assess myocardial perfusion and thus diagnose CAD in patients with indeterminate SPECT scan, or in patients for whom SPECT could be reasonably expected to be suboptimal in quality on the basis of body habitus.
For myocardial perfusion studies, patient selection criteria for PET scans involve an individual assessment of the pretest probability of CAD, based both on patient symptoms and risk factors:
The risk can be estimated using the patient's age, sex, and chest pain quality. The range for intermediate risk can vary.
The following table summarizes a characterization for patient populations at intermediate risk for CAD:
II. For Myocardial Viability:
Cardiac PET scanning may be considered medically necessary to assess the myocardial viability in patients with severe left ventricular dysfunction as a technique to determine candidacy for a revascularization procedure (e.g., PET scans are commonly performed in potential heart transplant candidates to rule out the presence of viable myocardium).
III. Diagnosis of Cardiac Sarcoidosis
Cardiac PET scanning may be considered medically necessary for the diagnosis of cardiac sarcoidosis in patients who are unable to undergo magnetic resonance imaging (MRI) scanning. Examples of patients who are unable to undergo MRI include, but are not limited to, patients with pacemakers, automatic implanted cardioverter-defibrillators (AICDs), or other metal implants.
IV. Quantification of Myocardial Blood Flow
Cardiac PET scanning is investigational for quantification of myocardial blood flow in patients diagnosed with CAD.
Myocardial Perfusion Imaging
SPECT scanning can be limited by body habitus, particularly by moderate to severe obesity, which can cause attenuation of tissue tracer leading to inaccurate images. In patients for whom body habitus is expected to lead to suboptimal SPECT scans, PET scanning is preferred.
Patients selected to undergo PET scans for myocardial viability are typically those with severe left ventricular dysfunction being considered for revascularization. A PET scan may determine whether the left ventricular dysfunction is related to viable or non-viable myocardium. Patients with viable myocardium may benefit from revascularization, while those with non-viable myocardium will not. As an example, PET scans are commonly performed in potential heart transplant candidates to rule out the presence of viable myocardium.
For both of these indications, a variety of studies have suggested that PET scans are only marginally more sensitive or specific than SPECT scans. Therefore, the choice between a PET scan (which may not be available locally) and a SPECT scan represents another clinical issue. PET scans may provide the greatest advantage over SPECT scans in moderately to severely obese patients for whom tissue attenuation of tracer is of greater concern.
Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Nervous/Mental Conditions, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:
A. consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and
B. appropriate with regard to standards of good medical practice; and
C. not solely for the convenience of the Member, his or her Provider; and
D. the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.
For the definition of Medically Necessary, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.
Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member’s specific benefit plan language.
POLICY HISTORY11/18/2009: Policy added as a result of the decision to separate the Positron Emission Tomography (PET) medical policy into application specific policies, this one addressing cardiac applications only. Upon creation of this separate policy, cardiac applications have been revised as outlined: The Policy Description Section revised for a clearer understanding of PET specific to cardiac applications, Policy Statement Section revised to add diagnosing CAD to medically necessary implications for myocardial perfusion studies, and added a guideline for CAD risk factors, Policy Coding Section updated to include Covered Codes specific to cardiac applications for PET, and added non-Covered Codes Table.
04/20/2010: Policy reviewed. No changes to policy description; statement unchanged. Added additional patient selection criteria to the Policy Guidelines section. Minor typographical errors corrected.
08/23/2011: The first policy statement was revised to change "in patients who may be prone to artifact that could lead to an indeterminate test, such as severely obese (BMI>35 kg/m2) patients" to "in patients for whom SPECT could be reasonably expected to be suboptimal in quality on the basis of body habitus." Added medically necessary policy statement regarding diagnosis of cardiac sarcoidosis.
09/25/2012: Policy reviewed; no changes.
05/07/2013: Removed ICD-9 procedure code 87.42 from the Code Reference section.
11/06/2013: Policy reviewed; no changes.
10/30/2014: Policy reviewed; description updated. Policy statement unchanged.
08/25/2015: Code Reference section updated for ICD-10.
03/29/2016: Policy description updated. Added the following policy statement: Cardiac PET scanning is investigational for quantification of myocardial blood flow in patients diagnosed with CAD. Policy guidelines updated to add section headings and information regarding SPECT scanning. Added medically necessary and investigative definitions.
SOURCESBlue Cross Blue Shield Association policy # 6.01.20
CODE REFERENCEThis may not be a comprehensive list of procedure codes applicable to this policy.
The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.
A PET scan essentially involves 3 separate activities:
When the radiopharmaceutical is provided by an outside distribution center, there may be an additional separate charge, or this charge may be passed through and included in the hospital bill. In addition, there will likely be an additional transportation charge for radiopharmaceuticals that are not manufactured on site.
PET imaging, any site, not otherwise specified
Fluorine-18 fluorodeoxyglucose (F-18 FDG) imaging using dual-head coincidence detection system (nondedicated PET scan)