Initial Physician Experience with [18F]Flutemetamol Amyloid PET Imaging Following Availability for Routine Clinical Use in Japan

Abstract

Background: Brain amyloid is a neuropathological hallmark of Alzheimer's disease (AD). By visualizing brain amyloid, positron emission tomography (PET) may influence the diagnostic assessment and management of patients with cognitive impairment. Objective: As part of a Japanese post-approval study to measure the safety of [ 18 F]flutemetamol PET, the association of amyloid PET results with changes in diagnosis and diagnostic confidence was assessed. Methods: Fifty-seven subjects were imaged for amyloid PET using [ 18 F]flutemetamol at a single Japanese memory clinic. The cognitive diagnosis and referring physician's confidence in the diagnosis were recorded before and after availability of PET results. Imaging started approximately 90 minutes after [ 18 F]flutemetamol administration with approximately 185 MBq injected. PET images were acquired for 30 minutes. Results: Amyloid PET imaging led to change in diagnosis in 15/44 clinical subjects (34%). Mean diagnostic confidence increased by approximately 20%, from 73% pre-scan to 93% post-scan, and this rise was fairly consistent across the main patient subgroups (mild cognitive impairment, AD, and non-AD) irrespective of the pre-scan diagnosis and scan result. Conclusion: The study examined the utility of amyloid PET imaging in a Japanese clinical cohort and highlighted the use of an etiological diagnosis in the presence of the amyloid scan. [ 18 F]Flutemetamol PET led to a change in diagnosis in over 30% of cases and to an increase in diagnostic confidence by approximately 20% consistent with other reports.

Clinical Effect of Early vs Late Amyloid Positron Emission Tomography in Memory Clinic Patients

“…The main outcome of the study was the proportion of participants receiving an etiological diagnosis with very high diagnostic confidence (ie, ≥90%) after 3 months (the period when the diagnostic process is generally completed) in arm 1 vs arm 2. The choice of this main outcome was based on previous studies showing that the etiological diagnosis of patients with a diagnostic confidence greater than 90% does not change following amyloid PET 19 and that the maximal mean diagnostic confidence post amyloid PET is 86% to 93%, [5][6][7]10 suggesting that this level of diagnostic confidence is a strong, achievable, and replicable reference standard.…”

“…Vitamin deficiency 100 (13) 32 ( 12) 41 ( 16) 27 (10) Self-sufficiency Disabilities 59 ( 7) 20 ( 7) 21 ( 8) 18 (7) Living in institution 5 (0) 0…”

“…Despite the increasing use of amyloid PET in clinical practice, real-world evidence about its clinical utility and cost-effectiveness is still limited. 3 Indeed, although several studies have been published so far, [4][5][6][7][8][9][10] they lack key features (eg, a control group) to provide conclusive evidence.…”

Quantification of amyloid PET for future clinical use: a state-of-the-art review

“…Routine clinical use of amyloid PET tracers involves visual assessment and binary categorisation of scans, based on tracer-specific manufacturers’ guidelines [ 24 – 26 ]. Classification is either negative (predominantly white matter uptake) or positive (binding in one or more cortical brain regions, or the striatum for [ 18 F]flutemetamol and [ 11 C]PiB).…”

Diagnostic Efficacy of Voxel-Mirrored Homotopic Connectivity in Vascular Dementia as Compared to Alzheimer’s Related Neurodegenerative Diseases—A Resting State fMRI Study

“…The symptom of VD is subtle and temporary, and it is difficult to be detected [ 3 ]. Current neuroimaging techniques for dementia diagnosis mainly focus on detection of brain structural and functional changes: structural MRI to detect hippocampal atrophy and its correlation with progression of disease from MCI to AD [ 4 , 5 , 6 , 7 ]; Positron Emission Tomography imaging (PET) using 18F-FDG as tracer to detect metabolic reduction in AD and MCI [ 8 ]; 18F-Flumetametamol as tracer to detect amyloid deposition for AD [ 9 , 10 , 11 ]. For VD, structural imaging is the main technique to detect silent brain infarcts and medial temporal lobe atrophy [ 12 , 13 ].…”