Amyloid PET imaging has been considered as a major advance in the clinical assessment of patients with cognitive impairment; however there is lack of agreement regarding the use of Amyloid PET scanning in the routine clinical evaluation of dementia. The Alzheimer's Association and the Society of Nuclear Medicine and Molecular Imaging formulated appropriate use criteria (AUC) for amyloid PET imaging in clinical settings especially when knowledge of the presence or absence of amyloid-beta pathology is expected to increase diagnostic certainty and alter the clinical management of the patients. Aims; To analyse the evidence for the use of Amyloid PET scanning in the clinical context and to understand whether any baseline clinical variables reliably differentiated negative from positive Amyloid -PET scan patients.
In this observational cohort study we analysed the clinical data for 35 patients meeting AUC who had F-18 florbetapir Amyloid PET scans.
42% (15/35) Amyloid positivity was observed in the cohort. The positivity in the subgroup of Amnestic Mild Cognitive Impairment (aMCI) was 75% followed by Probable Alzheimer's Disease (AD) 66.6%, Possible AD 43% and complex patients with diagnostic uncertainty 30%.
The data confirms that the presence/absence of amyloid pathology in the brain on amyloid PET scans, can serve as important diagnostic confirmatory tool even when the diagnosis is made by expert clinicians. Also it shows that in clinically challenging presentations of dementia syndrome with a heterogeneous aetiology, confirmation of the absence of amyloid brain pathology can aid in excluding AD. Other significant observations in the study include increased amyloid positivity in the aMCI group with stronger correlation with reduced perfusion to temporo-parietal region on a blood flow SPECT scan and the presence of family history of AD.
© 2016 Published by Elsevier Inc.