Groups release appropriate use criteria for amyloid PET

The Society of Nuclear Medicine and Molecular Imaging and the Alzheimer's Association recently released appropriate use criteria for amyloid positron emission tomography (PET) in clinical practice.

The two groups convened a task force to look at specific clinical scenarios in which amyloid PET could be considered appropriate. Elevated levels of amyloid plaques on PET can be an indicator of Alzheimer's disease but can also be present in normal elderly people and in patients with other clinical syndromes, the authors wrote. Their goal was to carefully examine the role of amyloid PET and its potential place in clinical practice, providing clinicians with information to help them give optimal care while also considering cost-effectiveness. The task force evaluated peer-reviewed published studies and developed recommendations based on consensus expert opinion.

The task force concluded that amyloid imaging is appropriate in patients with persistent or progressive mild cognitive impairment, patients who satisfy core criteria for Alzheimer's disease but have unclear clinical presentation, and patients with progressive dementia and atypically early age of onset (usually ≤65 years), if all of the following criteria are also met:

• The patient has a cognitive complaint with objectively confirmed impairment.
• Alzheimer's disease is a possible diagnosis, but diagnosis remains uncertain after comprehensive evaluation by a dementia expert.
• Knowledge of the presence or absence of amyloid plaque pathology is expected to increase diagnostic certainty and change management.

The task force concluded that amyloid imaging is inappropriate:

• in patients with core clinical criteria for probable Alzheimer's disease and typical age of onset,
• to determine dementia severity,
• based only on a family history of dementia or presence of apolipoprotein E ε4,
• in patients with a cognitive complaint that is unconfirmed on clinical exam,
• in place of genotyping for suspected autosomal mutation carriers,
• in asymptomatic individuals and
• for nonmedical use.

The task force also discussed the limitations of amyloid PET in clinical evaluation, its anticipated impact on patient care, and areas for further research. The full document is available free of charge online.