Positron emission tomography (PET) is not medically indicated when performed to monitor a planned course of treatment when no change in treatment is being contemplated. As such, this use of PET is not eligible for reimbursement.

In all situations, clinical documentation must be maintained in the patient's medical files to support the medical necessity for the PET procedure.

When a PET procedure is denied as not medically necessary, a participating, preferred, or network provider cannot bill the member for the denied service.

PET imaging used to evaluate asymptomatic patients is considered screening, that is, testing a patient without specific signs and/or symptoms of disease. Coverage for PET studies performed as a screening study is determined according to individual or group customer benefits.

PET imaging is considered medically necessary for the following nonmalignant applications and uses.

Brain for Refractive Seizures (Code G0229)
PET imaging of the brain is eligible in the presurgical evaluation of refractory seizures (345.00-345.01, 345.2, 345.3, 345.40-345.91). PET imaging of the brain for nonmalignant conditions other than the presurgical evaluation for localizing a focus of refractory seizure activity is considered not medically necessary. A participating, preferred, or network provider cannot bill the member for the denied service.

Brain for Dementia and Neurodegenerative Diseases (Code G0336)
One PET scan of the brain per lifetime is eligible for patients with a recent diagnosis of dementia and documented cognitive decline of at least six months, and who meet the diagnostic criteria for Alzheimer’s disease (AD) (331.0) and frontotemporal dementia (FTD) (331.11, 331.19). 

Scientific evidence has not established that PET studies of the brain are reasonable and necessary for diagnosing patients with mild cognitive impairment, early dementia (in clinical circumstances other than that specified above), or other dementia-causing neurodegenerative diseases or conditions (for example, possible or probable AD, clinically typical FTD, dementia of Lewy bodies, or Creutzfeldt-Jacob disease).  As such, PET imaging of the brain for other non-malignant cognitive conditions or dementias will be denied as not medically necessary. A participating, preferred, or network provider cannot bill the member for the denied service in this situation. 

A PET scan of the brain is eligible for payment for the differential diagnosis of frontotemporal dementia and Alzheimer’s disease when the following criteria are met. 

• The onset, clinical presentation, or course of cognitive impairment is atypical for AD, and FTD is suspected as an alternative neurodegenerative cause of the cognitive decline.
  
  
• The patient has had a comprehensive clinical evaluation as defined by the American Academy of Neurology (AAN). It must include a medical history from the patient and a well-acquainted associate, an assessment of activities of daily living, physical and mental status examinations (including formal documentation of cognitive decline occurring over at least six months) aided by cognitive scales or neuropsychological testing, laboratory tests, and structural imaging such as magnetic resonance imaging (MRI) or computed tomography (CT).
  
  
• A physician experienced in the diagnosis and assessment of dementia conducted the comprehensive clinical evaluation.
  
  
• The evaluation did not clearly identify a specific neurodegenerative disease or cause for the clinical symptoms, and information acquired through the PET study is reasonably expected to clarify the diagnosis and/or guide future treatment.
  
  
• The PET scan is performed in a facility accredited to operate such equipment and is interpreted by an expert in nuclear medicine, radiology, neurology, or psychiatry who has experience interpreting such scans in the presence of dementia.
  
  
• A brain single photon emission computed tomography (SPECT) or PET scan has not been performed for the same indication.

The following information must be documented in the patient’s clinical records and available for review upon request. 

• The date of onset of symptoms;
• Diagnosis of clinical syndrome (normal aging; mild cognitive impairment (MCI); moderate or severe dementia);
• Mini mental status exam (MMSE) or similar test score;
• Presumptive cause (possible, probable, uncertain AD);
• Any neuropsychological testing performed;
• Results of structural imaging (MRI, CT);
• Relevant laboratory tests (B12, thyroid hormone);
• Number and name of prescribed medications.

All other uses of PET studies for patients with a presumed diagnosis of dementia-causing neurodegenerative disease that are not described above are considered not medically necessary. This includes the differential diagnosis of AD from neurodegenerative diseases other than FTD.

Myocardium/Heart (Codes 78459, 78491, 78492, G0030-G0047, G0230)
A myocardial SPECT study is typically performed to distinguish between dysfunctional, but viable, myocardial tissue and scar tissue. This information helps to identify patients with compromised ventricular function, partial loss of heart muscle movement, or hibernating myocardium who may be candidates for a revascularization procedure. When the results of the SPECT study are in doubt or inconclusive, a PET study of the myocardium, whether at rest alone or rest with stress, may be used to obtain the necessary information.

PET imaging of the myocardium following an inconclusive SPECT study is useful in assessing myocardial perfusion in the diagnosis and treatment of coronary artery disease, and myocardial viability as a technique to determine a patient's candidacy for a revascularization procedure (410.00-410.92, 411.0-411.1, 411.81-411.89, 413.0-413.9, 414.00-414.07, 414.10-414.19, 414.8-414.9). As such, when a patient has received a myocardial SPECT test and the results are in doubt or inconclusive, a PET study of the myocardium, whether at rest alone or rest with stress, is considered an eligible procedure.

PET imaging of the myocardium for all other conditions is considered not medically necessary. A participating, preferred, or network provider cannot bill the member for the denied service.

PET Scans Using a Coincidence Detection System (Code S8085)
A Coincidence Detection System uses a modified SPECT gamma camera that has been adapted to produce PET-like images. Every PET scan performed on a Coincidence Detection Imaging System should be reported using code S8085 - FDG imaging using dual-head coincidence detection system (non-dedicated PET scan). Medical necessity guidelines applicable to PET studies as described in this policy apply to code S8085 as appropriate for the anatomic area imaged.

Radiopharmaceutical Diagnostic Imaging Agents
The cost of the radiopharmaceutical diagnostic imaging agent used to perform PET scans is included in the technical component and global allowance for the PET scan; therefore no separate payment can be made. There is one exception: the radiopharmaceutical tracers Rubidium 82 (code Q3000) and Ammonia N-13 (code A9526) will be reimbursed separately when reported with PET for myocardial perfusion (procedure codes 78491, 78492, G0030-G0047) but only when the study itself is eligible.

Description

PET is a nuclear imaging technology that uses positron emitting radiotracers coupled to organic molecules (e.g., glucose) to obtain both metabolic and physiologic information pertaining to a specific anatomic area. These radiotracers are produced by a nuclear generator or cyclotron and administered intravenously as radiopharmaceutical diagnostic imaging agents prior to imaging.

PET provides cross-sectional images of an anatomic area to identify metabolic, biochemical, hemodynamic, pharmacologic, and physiologic processes for the diagnosis and treatment management of diseases.

This policy focuses on the use of PET for applications other than tumor imaging.

For information on the oncologic applications of PET imaging in diagnosing and treating various malignancies, see Medical Policy Bulletin R-9; for information on PET/CT fusion imaging, see Medical Policy Bulletin R-16.

NOTE:

This policy is designed to address medical guidelines that are appropriate for the majority of individuals with a particular disease, illness, or condition. Each person's unique clinical circumstances may warrant individual consideration, based on review of applicable medical records.

PRN References

04/1996, Positron emission tomography
10/1999, Blue Shield allows positron emission tomography (PET) of the myocardium
04/2000, Coverage of positron emission tomography summarized
04/2001, Guidelines for reporting PET scans performed on coincidence detection imaging systems
08/2001, Coverage of PET imaging expanded
12/2004, Coverage added for PET imaging for Alzheimer's disease

Cardiac Positron Emission Tomography, Seminars in Nuclear Medicine, Vol. XXVIII, No. 4, 10/98

Assessment of Diagnostic Performance of Quantitative Flow Measurements in Normal Subjects and Patients with Angiographically Documented Coronary Artery Disease by Means of Nitrogen-13 Ammonia and Positron Emission Tomography, The Journal of the American College of Cardiology, Vol. 31, No. 3, 3/98

The Usefulness of Positron Emission in Tomography, Current Problems in Cardiology, 2/98

CMS Online Manual Pub. 100-3, Chapter 1, Section 220.6

CMS Online Manual Pub. 100-4, Chapter 13, Section 60

CMS Transmittals 136 and AB-01-54, CR1603

CMS Transmittal 24, CR 3426