Positron emission tomography (PET) images biochemical and physiologic functions by measuring concentrations of radioactive chemicals that have been partially metabolized in a particular region of the body. Radiopharmaceuticals used for PET are generated in a cyclotron (nuclear generator), and then introduced into the body by intravenous injection or respiration.

For individuals who have epileptic seizures who are candidates for surgery who have fluorine 18 fluorodeoxyglucose PET (FDG-PET), the evidence includes 5 systematic reviews (following the publication of 3 TEC Assessments). Relevant outcomes are symptoms, change in disease status, functional outcomes, health status measures, quality of life, hospitalizations, medication use, and resource utilization. The TEC Assessments and Program in Evidence-based Care PET recommendation report both concluded that FDG-PET accurately localizes the seizure focus compared with appropriate reference standards. A recent systematic review suggested it was difficult to discern the incremental value of FDG-PET in patients who have foci well localized by ictal scalp electroencephalography and magnetic resonance imaging. The evidence on whether FDG-PET has a predictive value for a good surgical outcome is mixed. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.

For individuals who have suspected chronic osteomyelitis who receive FDG-PET, the evidence includes 2 meta-analyses and a prospective study published after the meta-analyses. Relevant outcomes are test accuracy and validity, other test performance measures, change in disease status, functional outcomes, quality of life, and hospitalizations. One systematic review and meta-analysis from 2013 of 9 studies revealed that FDG-PET and FDG-PET plus computed tomography were useful for diagnosing suspected osteomyelitis in the foot of patients with diabetes. The results of the second meta-analysis from 2005 showed that FDG-PET was the most accurate mode (pooled sensitivity, 96%; pooled specificity, 91%for diagnosing chronic osteomyelitis. The results appear to be robust across fairly diverse clinical populations, which strengthen the conclusions. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.

For individuals who have suspected Alzheimer disease who receive FDG-PET, the evidence includes 5 systematic reviews of observational studies and a retrospective study addressing clinical utility. Relevant outcomes are test accuracy and validity, other test performance measures, symptoms, quality of life, and hospitalizations. The studies included in the reviews were generally of poor quality. There is no standard cutoff for PET positivity for diagnosing Alzheimer disease, and many studies have not included postmortem confirmation of Alzheimer disease as the reference standard, leading to uncertainty about estimates of performance characteristics. FDG-PET may have high sensitivity and specificity for diagnosing Alzheimer disease, but there is little evidence comparing the performance characteristics of clinical diagnosis using PET with the clinical diagnosis not using PET; therefore, the incremental value of adding PET to the standard clinical diagnosis is unclear. No studies have reported on clinical outcomes of patients diagnosed with and without FDG-PET. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have suspected large vessel vasculitis who receive FDG-PET, the evidence includes 5 systematic reviews of observational studies. Relevant outcomes are test accuracy and validity, other test performance measures, symptoms, morbid events, quality of life, hospitalizations, and treatment-related morbidity. Most studies included in the reviews were small and lacked controls. The reported performance characteristics were heterogeneous, but reviewers were unable to determine the source of heterogeneity. Studies comparing PET with the true reference standard of biopsy or angiography are rare. There are no consensus criteria to define the presence of vascular inflammation by FDG-PET in large vessel vasculitis, and different parameters with visual and semiquantitative methods have been reported. Studies demonstrating changes in management based on PET results or improvements in clinical outcomes are lacking. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals who have diverse noncardiac or nononcologic conditions (eg, central nervous system, pulmonary, and musculoskeletal diseases) who receive FDG-PET, the evidence includes a few systematic reviews. Relevant outcomes are overall survival, symptoms, change in disease status, functional outcomes, health status measures, quality of life, hospitalizations, medication use, and resource utilization. Many studies cited in the reviews were small, retrospective, and published in the 1990s to early 2000s; further, many studies did not directly compare a modality with another in the same patient group—nor did they connect the PET results in individual patients to improved clinical outcomes. Additional studies are needed to demonstrate FDG-PET results can change management, and therefore improve patient outcomes to determine that FDG-PET is a clinically useful test. The evidence is insufficient to determine the effect of the technology on health outcomes.

Positron emission tomography (PET) using 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) may be considered medically necessary in:

1. the assessment of select patients with epileptic seizures who are candidates for surgery (see Policy Guidelines section)

2. the diagnosis of chronic osteomyelitis.

The use of FDG-PET for all other miscellaneous indications is investigational, including, but not limited to:

Central Nervous System Diseases

     Autoimmune disorders with central nervous system manifestations, including:

        o Behçet syndrome

        o lupus erythematosus

     Cerebrovascular diseases, including:

        o arterial occlusive disease (arteriosclerosis, atherosclerosis)

        o carotid artery disease

        o cerebral aneurysm

        o cerebrovascular malformations (arteriovenous malformation and Moya-Moya disease)

        o hemorrhage

        o infarct

        o ischemia

     Degenerative motor neuron diseases, including:

        o amyotrophic lateral sclerosis

        o Friedreich ataxia

        o olivopontocerebellar atrophy

        o Parkinson disease

        o progressive supranuclear palsy

        o Shy-Drager syndrome

        o spinocerebellar degeneration

        o Steele-Richardson-Olszewski syndrome

        o Tourette syndrome

     Dementias, including:

        o Alzheimer disease

        o multi-infarct dementia

        o Pick disease

        o frontotemporal dementia

        o dementia with Lewy bodies

        o presenile dementia

     Demyelinating diseases, such as multiple sclerosis

     Developmental, congenital, or inherited disorders, including:

        o adrenoleukodystrophy

        o Down syndrome

        o Huntington chorea

        o kinky-hair disease (Menkes disease)

        o Sturge-Weber syndrome (encephalofacial angiomatosis) and the phakomatoses

     Miscellaneous

        o chronic fatigue syndrome

        o sick building syndrome

        o posttraumatic stress disorder

     Nutritional or metabolic diseases and disorders, including:

        o acanthocytosis

        o hepatic encephalopathy

        o hepatolenticular degeneration

        o metachromatic leukodystrophy

        o mitochondrial disease

        o subacute necrotizing encephalomyelopathy

     Psychiatric diseases and disorders, including:

        o affective disorders

        o depression

        o obsessive-compulsive disorder

        o psychomotor disorders

        o schizophrenia

     Pyogenic infections, including:

        o aspergillosis

        o encephalitis

     Substance abuse, including the central nervous system effects of alcohol, cocaine, and heroin

     Trauma, including brain injury and carbon monoxide poisoning

     Viral infections, including:

        o HIV/AIDS

        o AIDS dementia complex

        o Creutzfeldt-Jakob syndrome

        o progressive multifocal leukoencephalopathy

        o progressive rubella encephalopathy

        o subacute sclerosing panencephalitis

     Mycobacterium infection

     Migraine

     Anorexia nervosa

     Assessment of cerebral blood flow in newborns

        o Vegetative vs locked-in syndrome

Pulmonary Diseases

     Adult respiratory distress syndrome

     Diffuse panbronchiolitis

     Emphysema

     Obstructive lung disease

     Pneumonia

Musculoskeletal Diseases

     Spondylodiscitis

     Joint replacement follow-up

Other

     Giant cell arteritis

     Vasculitis

     Vascular prosthetic graft infection

     Inflammatory bowel disease

     Sarcoidosis

     Fever of unknown origin

     Inflammation of unknown origin

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