Cognitive trajectories of patients with focal \xdf-amyloid deposition

Si Eun Kim ,Jee Hyang Jeong,Jin Yong Hong ,Hang‐Rai Kim ,Bora Yoon,Byungju Lee,Song Hwangbo,Soo Jin Yoon ,Sang Won Seo,Juhee Chin,Sung Hoon Kang ,Yeong Sim Choe ,Jae‐Won Jang ,Kyung Won Park ,Duk L Na,Ji Sun Kim ,Ching Soong Khoo,Hyemin Jang,Seong Hye Choi ,Eun-Joo Kim ,Hee Jin Kim

doi:10.1186/s13195-021-00787-7

Abstract

BackgroundThe presence of ß-amyloid (Aß) in the brain can be identified using amyloid PET. In clinical practice, the amyloid PET is interpreted based on dichotomous visual rating, which renders focal Aß accumulation be read as positive for Aß. However, the prognosis of patients with focal Aß deposition is not well established. Thus, we investigated cognitive trajectories of patients with focal Aß deposition.MethodsWe followed up 240 participants (112 cognitively unimpaired [CU], 78 amnestic mild cognitive impairment [aMCI], and 50 Alzheimer’s disease (AD) dementia [ADD]) for 2 years from 9 referral centers in South Korea. Participants were assessed with neuropsychological tests and 18F-flutemetamol (FMM) positron emission tomography (PET). Ten regions (frontal, precuneus/posterior cingulate (PPC), lateral temporal, parietal, and striatum of each hemisphere) were visually examined in the FMM scan, and participants were divided into three groups: No-FMM, Focal-FMM (FMM uptake in 1–9 regions), and Diffuse-FMM. We used mixed-effects model to investigate the speed of cognitive decline in the Focal-FMM group according to the cognitive level, extent, and location of Aß involvement, in comparison with the No- or Diffuse-FMM group.ResultsForty-five of 240 (18.8%) individuals were categorized as Focal-FMM. The rate of cognitive decline in the Focal-FMM group was faster than the No-FMM group (especially in the CU and aMCI stage) and slower than the Diffuse-FMM group (in particular in the CU stage). Within the Focal-FMM group, participants with FMM uptake to a larger extent (7–9 regions) showed faster cognitive decline compared to those with uptake to a smaller extent (1–3 or 4–6 regions). The Focal-FMM group was found to have faster cognitive decline in comparison with the No-FMM when there was uptake in the PPC, striatum, and frontal cortex.ConclusionsWhen predicting cognitive decline of patients with focal Aß deposition, the patients’ cognitive level, extent, and location of the focal involvement are important.

Highlights

IntroductionThe amyloid positron emission tomography (PET) is interpreted based on dichotomous visual rating, which renders focal Aß accumulation be read as positive for Aß
The presence of ß-amyloid (Aß) in the brain can be identified using amyloid positron emission tomography (PET)
There were studies that focused on regional Aß burden using standardized uptake value ratios (SUVR) [4,5,6], no previous study focused on longitudinal trajectories of focal Aß deposition based on visual rating

Summary

Introduction

The amyloid PET is interpreted based on dichotomous visual rating, which renders focal Aß accumulation be read as positive for Aß. Amyloid PET is interpreted based on a dichotomous visual rating that regards focal Aß deposition as positive [3]. Managing patients with focal Aß deposition on PET scan is challenging. Will these patients face cognitive decline in the near future and if so, what initial features may predict cognitive decline? There were studies that focused on regional Aß burden using standardized uptake value ratios (SUVR) [4,5,6], no previous study focused on longitudinal trajectories of focal Aß deposition based on visual rating

Methods

Results

Discussion

Conclusion