The use of positron emission tomography/magnetic resonance imaging in dementia: A literature review

Abstract

Objectives Positron emission tomography–magnetic resonance imaging (PET/MRI) is an emerging hybrid imaging system in clinical nuclear medicine. Research demonstrates a comparative utility to current unimodal and hybrid methods, including PET‐computed tomography (PET/CT), in several medical subspecialities such as neuroimaging. The aim of this review is to critically evaluate the literature from 2016 to 2021 using PET/MRI for the investigation of patients with mild cognitive impairment or dementia, and discuss the evidence base for widening its application into clinical practice. Methods A comprehensive literature search using the PubMed database was conducted to retrieve studies using PET/MRI in relation to the topics of mild cognitive impairment, dementia, or Alzheimer's disease between January 2016 and January 2021. This search strategy enabled studies on all dementia types to be included in the analysis. Studies were required to have a minimum of 10 human subjects and incorporate simultaneous PET/MRI. Results A total of 116 papers were retrieved, with 39 papers included in the final selection. These were broadly categorised into reviews (12), technical/methodological papers (11) and new data studies (16). For the current review, discussion focused on findings from the new data studies. Conclusions PET/MRI offers additional insight into the underlying anatomical, metabolic and functional changes associated with dementia when compared with unimodal methods and PET/CT, particularly relating to brain regions including the hippocampus and default mode network. Furthermore, the improved diagnostic utility of PET/MRI, as reported by radiologists, offers improved classification of dementia patients, with important implications for clinical management.

Investigation of the functional pathogenesis of mild cognitive impairment by localisation‐based locus coeruleus resting‐state fMRI

“…Dementia is one of the most prevalent and compelling diseases arising in the 21st century (Cao et al, 2020 ; Prince et al, 2013 ) with an expected number of 135 million patients worldwide in 2050 (Robinson et al, 2015 ). There is urgent need for an improvement of understanding of the underlying mechanisms in the brain responsible for clinical symptoms, and improvement and extension of diagnostic capabilities (Lorking et al, 2021 ; McCarthy et al, 2018 ; Tsoi et al, 2015 ). Especially, an early diagnosis is crucial for a timely intervention aiming at preventing disease progression and at alleviating of symptom severity (Barnett et al, 2014 ; Crous‐Bou et al, 2017 ; Robinson et al, 2015 ).…”

Current Trends and Applications of PET/MRI Hybrid Imaging in Neurodegenerative Diseases and Normal Aging

“…Overall, the number of reviews after filtering was 19.4% (18/93) of the eligible articles. Common themes across these review articles included the rise of artificial intelligence, technical improvements to PET/MRI imaging, and new and previous regions of interest for evaluating dementia [ 8 , 10 , 72 , 73 , 74 , 75 , 76 , 77 ]. The distribution of these article types remains consistent with this current review and is discussed further in the sections below along with additional insights from the clinical articles sourced in the past five years.…”

“…Previous review literature on hybrid PET/MR imaging in dementia was mostly limited to time periods before 2020 and has focused on various specifics such as changes in image acquisition settings, post-processing, regions of interest such as the hippocampus, and tracers [ 8 , 9 , 10 ]. As imaging continues to quickly improve, the purpose of this narrative review is to examine the latest articles published between 2018 and 2023 on the applications of PET/MRI in the characterization of various subtypes of dementia.…”