• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.112-117
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• 2007

Imaging distribution of ${\beta}-amyloid$ plaques in Alzheimer's disease is very important for early and accurate diagnosis. Early trial of the ${\beta}-amyloid$ plaques includes using radiolabeled peptides which can be only applied for peripheral ${\beta}-amyloid$ plaques due to limited penetration through the blood brain barrier (BBB). Congo red or Chrysamine G derivatives were labeled with Tc-99m for imaging ${\beta}-amyloid$ plaques of Alzheimer patient's brain without success due to problem with BBB penetration. Thioflavin T derivatives gave breakthrough for ${\beta}-amyloid$ imaging in vivo, and a benzothiazole derivative [C-11]6-OH-BTA-1 brought a great success. Many other benzothiazole, benzoxazole, benzofuran, imidazopyridine, and styrylbenzene derivatives have been labeled with F-18 and I-123 to improve the imaging quality. However, [C-11]6-OH-BTA-1 still remains as the best. However, short half-life of C-11 is a limitation of wide distribution of this agent. So, it is still required to develop an Tc-99m, F-18 or I-123 labeled agent for ${\beta}-amyloid$ imaging agent.

• Korean Journal of Radiology
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• v.25 no.8
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• pp.726-741
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• 2024

Recent advancements in Alzheimer's disease treatment have focused on the elimination of amyloid-beta (Aβ) plaque, a hallmark of the disease. Monoclonal antibodies such as lecanemab and donanemab can alter disease progression by binding to different forms of Aβ aggregates. However, these treatments raise concerns about adverse effects, particularly amyloid-related imaging abnormalities (ARIA). Careful assessment of safety, especially regarding ARIA, is crucial. ARIA results from treatment-related disruption of vascular integrity and increased vascular permeability, leading to the leakage of proteinaceous fluid (ARIA-E) and heme products (ARIA-H). ARIA-E indicates treatment-induced edema or sulcal effusion, while ARIA-H indicates treatment-induced microhemorrhage or superficial siderosis. The minimum recommended magnetic resonance imaging sequences for ARIA assessment are T2-FLAIR, T2^* gradient echo (GRE), and diffusion-weighted imaging (DWI). T2-FLAIR and T2^* GRE are necessary to detect ARIA-E and ARIA-H, respectively. DWI plays a role in differentiating ARIA-E from acute to subacute infarcts. Physicians, including radiologists, must be familiar with the imaging features of ARIA, the appropriate imaging protocol for the ARIA workup, and the reporting of findings in clinical practice. This review aims to describe the clinical and imaging features of ARIA and suggest points for the timely detection and monitoring of ARIA in clinical practice.

• Biomedical Science Letters
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• v.25 no.1
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• pp.7-14
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• 2019

Alzheimer's disease (AD) is highly prevalent in dementia, with no specifically effective treatment having yet been discovered. Amyloid plaques are one of the key hallmarks of AD. Transgenic mouse models exhibiting Alzheimer's disease-like pathology have been widely used to study the pathophysiology of Alzheimer's disease. In this study, we showed an age-dependent correlation between cognitive function, pathological findings, and [F-18] Florbetaben (FBB) PET images. Nineteen transgenic mice (12 with AD, 7 with controls) were used for this study. We observed an increase in ${\beta}$-Amyloid deposition ($A{\beta}$) in brain tissue and [F-18] FBB amyloid PET imaging in the AD group. The [F-18] FBB data showed a mildly negative trend with cognitive function. Pathological findings were negatively correlated with cognitive functions. These finding suggests that amyloid beta deposition can be well-monitored with [F-18] FBB PET and a decline in cognitive function is related to the increase in amyloid plaque burden.

• Dementia and Neurocognitive Disorders
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• v.22 no.3
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• pp.87-99
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• 2023

Background and Purpose: According to the amyloid cascade hypothesis, fibrillary amyloid-beta load in the brain causes Alzheimer's disease (AD) with toxic effects. Recently, perivascular spaces (PVSs), fluid-filled cavities around small penetrating arterioles and venules in the brain, and the glymphatic system relationship with type 2 diabetes mellitus (DM2) and AD has been an important research topic from a physiopathological point of view. There are two types of PVSs that are associated with sporadic atherosclerosis and cerebral amyloid angiopathy. In this study, we evaluated the relationship between the number and localization of enlarged PVSs in AD. Methods: A total of 254 patients with AD and 125 healthy controls were included in this study All the patients were evaluated with neurological and cognitive examinations and magnetic resonance imaging (MRI). PVSs on MRI were graded by recording their number and location. The study was a retrospective study. Results: In our study, the number of white matter convexity-central semiovale localized PVSs was higher in patients than in the control group. In addition, the number of PVSs in this localization score was higher in patients with DM2. Cerebral PVS counts were higher in patients with AD than in the control group. Conclusions: These results suggest the important role of cerebral amyloid angiopathy, one of the vascular risk factors, and the glymphatic system in the pathogenesis of AD. In addition, the results of our study suggest that the evaluation of PVSs levels, especially at the (centrum semiovale), using imaging studies in AD is a potential diagnostic option.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3671-3675
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• 2012

${\beta}$-Amyloid accumulation in the brain is a pathological hallmark of Alzheimer's disease (AD). Since early detection of ${\beta}$-amyloid may facilitate more successful and timely therapeutic interventions, many investigators have focused on developing AD diagnostic reagents that can penetrate the blood-brain barrier (BBB). Oleanolic acid (OA) is a substance found in a variety of plants that has been reported to prevent the progression of AD in mice. In this study, we synthesized and evaluated a new radioligand in which OA was conjugated to lactoferrin (Lf, an iron-binding glycoprotein that crosses the BBB) for the diagnosis of AD. In an in vitro study in which OA-Lf was incubated with ${\beta}$-amyloid (1-42) aggregates for 24 h, we found that OA-Lf effectively inhibited ${\beta}$-amyloid aggregation and fibril formation. In vivo studies demonstrated that $^{123}I$-OA-Lf brain uptake was higher than$^{123}I$-Lf uptake. Therefore, radiolabeled OA-Lf may have diagnostic potential for ${\beta}$-amyloid imaging.

• Journal of Yeungnam Medical Science
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• v.35 no.1
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• pp.1-6
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• 2018

Alzheimer's disease (AD) is a neurodegenerative disorder associated with extracellular plaques, composed of amyloid-beta ($A{\beta}$), in the brain. Although the precise mechanism underlying the neurotoxicity of $A{\beta}$ has not been established, $A{\beta}$ accumulation is the primary event in a cascade of events that lead to neurofibrillary degeneration and dementia. In particular, the $A{\beta}$ burden, as assessed by neuroimaging, has proved to be an excellent predictive biomarker. Positron emission tomography, using ligands such as $^{11}C$-labeled Pittsburgh Compound B or $^{18}F$-labeled tracers, such as $^{18}F$-florbetaben, $^{18}F$-florbetapir, and $^{18}F$-flutemetamol, which bind to $A{\beta}$ deposits in the brain, has been a valuable technique for visualizing and quantifying the deposition of $A{\beta}$ throughout the brain in living subjects. $A{\beta}$ imaging has very high sensitivity for detecting AD pathology. In addition, it can predict the progression from mild cognitive impairment to AD, and contribute to the development of disease-specific therapies.

• Journal of the Korean Society of Radiology
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• v.10 no.5
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• pp.307-312
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• 2016

Alzheimer's disease is the most common degenerative brain diseases that causes dementia. ${\beta}$-amyloid neuritic plaque density that accumulates in the brain is difficult to perform daily living, such as memory loss, language ability deterioration. It is used to estimate ${\beta}$-amyloid neuritic plaque density in adult patients with cognitive impairment who are being evaluated for Alzheimer's disease and other causes of cognitive impairment. Using the $^{18}F$-Florbetaben with high sensitivity and specificity for the ${\beta}$-amyloid neuritic plaque density to evaluate the usefulness for the early diagnosis of Alzheimer's disease. In $^{18}F$-FDG Brain imaging shows no specific findings. And it appeared on the MR-Brain imaging without atrophy of the hippocampus. However, the intake of ${\beta}$-amyloid neuritic plaque density in $^{18}F$-Florbetaben informs that it is the progress of Alzheimer's disease. Therefore, $^{18}F$-Florobetaben is very useful for early diagnosis of Alzheimer's disease.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4281-4281
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• 2012

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.453-472
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• 2022

Over the past decades, the immense clinical need for early detection methods and treatments for dementia has become a priority worldwide. The advances in PET biomarkers play increasingly important roles in understanding disease mechanisms by demonstrating the protein pathology underlying dementia in the brain. Amyloid-β and tau deposition in PET images are now key diagnostic biomarkers for the Alzheimer's disease continuum. The inclusion of biomarkers in the diagnostic criteria has achieved a paradigm shift in facilitating early differential diagnosis, predicting disease prognosis, and influencing clinical management. Furthermore, in vivo images showing pathology could become prognostic as well as surrogate biomarkers in therapeutic trials. In this review, we focus on recent developments in radiotracers for amyloid-β and tau PET imaging in Alzheimer's disease and other neurodegenerative diseases. Further, we introduce their potential application as future perspectives.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1231-1234
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• 2007