SPECT and PET imaging in Alzheimer’s disease

Abstract

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Beta-amyloid (Aβ) deposition and neurofibrillary tangles (NFTs) of abnormal hyperphosphorylated tau protein are the pathological hallmarks of the disease, accompanied by other pathological processes such as microglia activation. Functional and molecular nuclear medicine imaging with single-photon emission computed tomography (SPECT) and positron emission tomography (PET) techniques provides valuable information about the underlying pathological processes, many years before the appearance of clinical symptoms. Nuclear neuroimaging in AD has made great progress in the past two decades and has extended beyond the traditional role of brain perfusion and glucose metabolism evaluation. Intense efforts in radiopharmaceuticals research have led to the development of various probes able to detect Aβ deposits, tau protein accumulation, microglia activation and neuroinflammation. As a result, SPECT and PET have proposed to serve as biomarkers in recently revised diagnostic clinical criteria for the early diagnosis of AD and the prediction of progression to AD in mild cognitive impairment (MCI) subjects.

The role of artificial intelligence and machine learning in harmonization of high-resolution post-mortem MRI (virtopsy) with respect to brain microstructure

“…Furthermore, already routine diagnostic assessment of 3 T or 7 T images yields an immense body of biographical and clinical data of patients. Molecular imaging protocols provide additional aspects and data [70][71][72][73][74]. In animal research, mean diffusivity changes could be related to structural changes in astrocytes, myelin or synaptic remodelling [75,76].…”

Progress of RAGE Molecular Imaging in Alzheimer’s Disease

“…Several studies have documented other PET imaging probes for early AD diagnosis, such as those aimed at various targets, including Aβ, tau, and others. Tau-targeting imaging probes such as [ 18 F]-THK-5351, [ 18 F]-THK-5117, and [ 18 F]-AV-1451 show a high uptake in the patients’ cortex ( Harada et al, 2015 ; Lemoine et al, 2015 ; Passamonti et al, 2017 ; Kobayashi et al, 2018 ; Valotassiou et al, 2018 ), which means that they can accurately detect NFTs, thus helping in the early diagnosis of AD. At the same time, [ 11 C] PiB, an analog of thioflavin-T and a benzothiazole derivative, was the first probe specifically targeting Aβ ( Rabinovici et al, 2007 ; Lim et al, 2014 ; Lemoine et al, 2015 ; Kobayashi et al, 2018 ).…”

“…At the same time, [ 11 C] PiB, an analog of thioflavin-T and a benzothiazole derivative, was the first probe specifically targeting Aβ ( Rabinovici et al, 2007 ; Lim et al, 2014 ; Lemoine et al, 2015 ; Kobayashi et al, 2018 ). Since then, many new probes targeting Aβ have appeared, including [ 18 F]-florbetapir, [ 18 F]-florbetaben, and [ 18 F]-flutemetamol, all showing high affinity and specificity for Aβ ( Valotassiou et al, 2018 ). These tau and Aβ-targeting probes can also be used for quantification analysis to further validate the role of RAGE in the pathogenesis of AD ( Fang et al, 2018 ).…”

Elevated plasma biomarkers of inflammation in acute ischemic stroke patients with underlying dementia

“…The ideal diagnostic test would accurately reveal disease attributes across all tested populations, while being convenient, inexpensive, and safe. Such an ideal test for AD still lies in the future, but there has been progress in developing CSF-based biochemical tests [ 1 ] and positron emission tomography (PET) tests utilizing ligands for amyloid β protein or tau protein [ 2 ]. Blood-based tests would be preferable to these in terms of cost and patient acceptance, but have been challenging to develop, other than genetic tests for familial disorders.…”