Diagnostic impact of [18F]flutemetamol PET in early-onset dementia

Marissa D Zwan,Pauline Aalten,Philip Scheltens,Wiesje M Van Der Flier,Adriaan A Lammertsma,Elles Konijnenberg,Frans R J Verhey,Bart N M Van Berckel,Femke H Bouwman

doi:10.1186/s13195-016-0228-4

Abstract

BackgroundEarly-onset dementia patients often present with atypical clinical symptoms, hampering an accurate clinical diagnosis. The purpose of the present study was to assess the diagnostic impact of the amyloid-positron emission tomography (PET) imaging agent [18F]flutemetamol in early-onset dementia patients, in terms of change in (confidence in) diagnosis and patient management plan.MethodsThis prospective bi-center study included 211 patients suspected of early-onset dementia who visited a tertiary memory clinic. Patients were eligible with Mini Mental State Examination ≥ 18 and age at diagnosis ≤ 70 years and in whom the diagnostic confidence was <90% after routine diagnostic work-up. All patients underwent [18F]flutemetamol PET, which was interpreted as amyloid-negative or amyloid-positive based on visual rating. Before and after disclosing the PET results, we assessed the diagnostic confidence (using a visual analog scale of 0–100%) and clinical diagnosis. The impact of [18F]flutemetamol PET on the patient management plan was also evaluated.Results[18F]flutemetamol PET scans were positive in 133 out of 211 (63%) patients, of whom 110 out of 144 (76%) patients had a pre-PET Alzheimer’s disease (AD) diagnosis and 23 out of 67 (34%) patients had a non-AD diagnosis. After disclosure of PET results, 41/211 (19%) diagnoses changed. Overall, diagnostic confidence increased from 69 ± 12% to 88 ± 15% after disclosing PET results (P < 0.001; in 87% of patients). In 79 (37%) patients, PET results led to a change in patient management and predominantly the initiation of AD medication when PET showed evidence for amyloid pathology.Conclusions[18F]flutemetamol PET changed clinical diagnosis, increased overall diagnostic confidence, and altered the patient management plan. Our results suggest that amyloid PET may have added value over the standardized diagnostic work-up in early-onset dementia patients with uncertain clinical diagnosis. This study provides evidence for the recommendations put forward in the appropriate use criteria for amyloid PET in clinical practice.Trial registrationNederlands Trial Register NTR3743. Registered 7 December 2012.

Highlights

Early-onset dementia patients often present with atypical clinical symptoms, hampering an accurate clinical diagnosis
Patients The present study included a consecutive series of patients visiting a Dutch tertiary memory clinic and suspected of mild dementia (defined as Mini Mental State Examination (MMSE) score ≥ 18) or early-onset dementia, who had no firm diagnosis after the standardized dementia evaluation or persisting diagnostic uncertainty
Clinical diagnosis In 59 (28%) patients, the positron emission tomography (PET) findings were inconsistent with expected PET results prior to scanning

Summary

Introduction

Early-onset dementia patients often present with atypical clinical symptoms, hampering an accurate clinical diagnosis. The purpose of the present study was to assess the diagnostic impact of the amyloid-positron emission tomography (PET) imaging agent [18F]flutemetamol in early-onset dementia patients, in terms of change in (confidence in) diagnosis and patient management plan. Patients with early-onset Alzheimer’s disease (AD) more often present with atypical clinical symptoms, such as difficulties with vision or speech, behavioral changes, or Several fluorine-18-labeled positron emission tomography (PET) tracers, including [18F]flutemetamol, have become available for clinical practice and incorporated as amyloid pathology biomarkers in the revised research criteria for AD [3]. The aim was to assess the impact of [18F]flutemetamol PET on (confidence in) clinical diagnosis and patient management plan

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