Amyloid Imaging Task Force revamps appropriate use criteria

The Amyloid Imaging Task Force, a collaborative effort by the Alzheimer’s Association and the Society of Nuclear Medicine and Molecular Imaging (SNMMI), published an update to previous appropriate use criteria for amyloid imaging as it relates to suspected Alzheimer’s disease pathology June 10 in the Journal of Nuclear Medicine.

Keith A. Johnson, MD, from the departments of radiology and neurology at Massachusetts General Hospital, Harvard Medical School in Boston, and colleagues expounded on the original appropriate use criteria publication released earlier this year by outlining how an Alzheimer’s expert should be defined, what patient documentation should be observed to determine the need for amyloid imaging, and by providing examples of when it is appropriate to use amyloid imaging for those with mild cognitive impairment or etiologic uncertainty and for those who would have a change in management. The paper also indicates ideal methods for physician and patient education and outreach to improve understanding of amyloid imaging and how it should be applied to improve clinical decision-making.

Dementia experts were more clearly defined as those with “clinical training, substantial clinical experience and practice in dementia care,” wrote Johnson et al. “A high level of clinical experience with elderly patients and cognitive impairment is needed for the dementia expert to understand and properly apply the multifaceted consensus clinical criteria that define specific phases of Alzheimer disease dementia and predementia.”

Training and board-certification in neurology, psychiatry or geriatric medicine would be compulsory, with at least 25 percent of patient face-time devoted to cognitive impairment and dementia, including suspected Alzheimer’s disease. 

“This level of expertise and familiarity is needed because amyloid PET is not a test for dementia or clinical Alzheimer disease but rather is an indicator of underlying pathology, which can be useful only when a particular clinical syndrome has been identified and other explanations have been adequately considered after a proper clinical evaluation,” wrote the authors.

Documentation of medical necessity was presented in a diagnostic checklist that included identification of clinical syndrome, objective mental assessment like that of the Mini-Mental State Examination, a listing of comorbidities, medications, results of neuroimaging and other relevant testing.

“We recommend that the dementia expert and PET physician be required to document this information in the medical record of each patient,” the authors wrote. “Third-party payers should consider this information fully sufficient to demonstrate the medical necessity of amyloid PET, and this information could be submitted to payers on request. This information also could be the basis for sponsorship of a voluntary registry for independent assessment of appropriate use and for targeting of educational efforts.”

For those with mild cognitive impairment, appropriate use was determined if physicians review the checklist and still find amyloid PET appropriate for these patients. Sources of etiologic uncertainty were mentioned, which can happen while diagnosing MCI or Alzheimer disease dementia. These were indicated as atypical or sudden clinical onset, or in the presence of vascular or Lewy pathology or when “confounding circumstances” cloud certainty, such as in the case of interfering medical disorders, medication, substance abuse or depression. In such circumstances, the Task Force deemed it appropriate to use amyloid imaging to avoid unnecessary delays in treatment.

“In these relatively unusual but important cases, substantial uncertainty then remains as to the cause of the syndrome, and further patient care is severely constrained or compromised,” they wrote. “The treating physician must then adopt a wait-and-see approach that is unsatisfying, potentially misguided, at times wasteful, and potentially harmful.”

Amyloid PET imaging also was deemed appropriate if a substantial change in diagnostic certainty or patient management was expected.

The perspective piece included examples of educational outreach to improve dementia, amyloid imaging and appropriate-use awareness among physicians and patients. The Task Force aims to continue creating educational materials to ensure appropriate use of amyloid imaging and to support local and national meetings and national distribution of educational materials.