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HOW AMYLOID PET CHANGES COGNITIVE CARE: A BROADER VIEW

      Background

      Amyloid PET imaging is a reliable biomarker of Alzheimer’s disease pathology and could prove valuable in clinical care. A standard formulation is that diagnostic testing should be performed only if it modifies drug or surgical treatment. There are, however, many additional reasons for knowing the cause of the cognitive impairment with greater certainty. Although some recommendations are relevant irrespective of diagnosis, others depend upon the specific cause of cognitive impairment identified. Provider confidence in the diagnosis also affects the willingness to discuss difficult, lifechanging recommendations.

      Methods

      We identified 8 independent, non-drug care recommendations that would be altered depending upon the cause of cognitive impairment and used them as outcomes in a study of the clinical use of amyloid PET. Amyloid PET with 18F-flutemetamol was performed in 15 patients (9 men, 6 women, mean age 64.6, age range 51-85) whose diagnosis was uncertain after an otherwise complete dementia specialist evaluation. Scans were read visually, aided by quantitative analysis using Cortex ID software and classified as either positive indicating significant pathology or negative. We evaluated changes in physician diagnosis, diagnostic confidence and recommended care practices before and after amyloid PET imaging.

      Results

      Significant binding in the cerebral cortex was present in 13 (87%) of the scans. In 14 patients (82%) recommended care practices changed after amyloid PET. These recommendations involved planning for likely stable or progressive disease course (33% change), monitoring for disease complications (13%), disease specific education (40%) and referrals. Scans stimulated referrals to develop a family plan of progressive support in 27% and to a psychiatrist in 20%. The most frequent change in care practices was referral to a Alzheimer clinical trial (53%). The diagnosis judged most likely before the scan changed in 27% and there was a 90% increase in diagnostic confidence after the amyloid PET.

      Conclusions

      The classification of Alzheimer’s pathology with amyloid PET frequently changes provider recommendations that depend upon a specific diagnosis. Changes in recommended non-drug care practices contribute to the value of amyloid PET. Further experience is needed to fully understand the role of amyloid classification technology in clinical practice.