Introduction: Alzheimer’s disease (AD) is the most common type (75.0%) of all dementia types in Thailand. The current study was conducted to improve the understanding of relationships between regional cortical amyloid load, glucose metabolism, cortical morphology (thickness), and severity of clinical symptoms in patients with AD, MCI, and age-matched controls.Methods: To objectivize the radiological evaluation of patients with suspected AD, head-to-head multi-modality imaging studies were conducted using MRI and PET/CT with [18F]FDG and [18F]AV45 for visualization and quantitation of brain morphology, glucose metabolism, and amyloid levels, respectively.  A total of 84 subjects were studied, including: 33 patients with AD, 31 patients with MCI, and 20 age-matched healthy controls (HC). A new quantitative index was calculated as a ratio of regional SUV of [18F]AV45 (normalized to cerebellar cortex) over the corresponding regional SUV of [18F]FDG, divided by the corresponding regional volume, measured from the co-registered MRI and normalized to the normal age-matched control group (AV45/FDG/NVol index). Relationships between clinical scores (TMSE, ADAS) and AV45/FDG/NVol indices for different structures of the brain in study groups were determined using linear regression analyses. Temporal dynamics of amyloid levels, glucose metabolism, regional brain volume, and neurocognitive performance in patients with Alzheimer’s disease were studied over 2 years.Results: A significant direct linear correlation was observed between the AV45/FDG/NVol index and ADAS-Cog test score and an inverse correlation with TMSE score at baseline and with the degree of changes in ADAS and TMSE scores assessed one year later (disease progression). The observed correlations between AV45/FDG/NVol index and clinical scores were significantly stronger than with individual parameters: cerebellum-normalized AV45 SUV, FDG SUV, or MRI-based volumes of brain cortical regions and different structures. Temporal dynamics of amyloid levels, glucose metabolism, regional brain volumes, and neurocognitive performance determined over 2 years of observation confirmed the leading role of amyloid buildup in the progression of Alzheimer’s disease as measured by the degree of cognitive decline. Conclusions: The current study demonstrated that AV45/FDG/NVol index mapping of the brain is a novel quantitative molecular imaging biomarker that correlates with clinical neurocognitive status and may facilitate more accurate diagnosis, staging, and prognosis of AD. Additional larger-scale clinical studies are required to further evaluate the efficacy of this new quantitative index as a diagnostic and prognostic biomarker of AD as well as for evaluation of safety and efficacy of novel drugs undergoing clinical trials for the therapy of AD.

Juri George Gelovani received an M.D. degree in 1986, at the age of 22, and a Ph.D. degree in 1990, at the age of 26, both from the University of Tartu (Estonia), specializing in Neurosurgery. In 1991-1996, He was a Fellow in Neuro-Oncology at the Memorial Sloan Kettering Cancer Center (New York, NY), then Assistant Professor (1996), and Associate Professor (1999). In 2003, he joined the MD Anderson Cancer Center (Houston, TX) as Professor and Chair of Experimental Imaging and Director Center for Advanced Biomedical Imaging Research (CABIR). In 2001, he was awarded the 1st Gold Medal by the Society of Molecular Imaging (SMI). In 2004, he received the George and Barbara Bush Award for Innovation in Cancer Research. In 2008, he served as the President of the Society for Molecular Imaging. In 2010, he served as President of the Academy of Molecular Imaging, and in 2011 he served as President of the World Molecular Imaging Society (WMIS). In 2012, he moved to Wayne State University (Detroit, MI), as a Professor of Oncology and Neurosurgery, Chair of Biomedical Engineering, and Leader of the Molecular Imaging Program at Karmanos Cancer Institute. In 2020, Dr. Gelovani joined the United Arab Emirates University (Al Ain, UAE) as an Associate Provost for Academic Affairs and Currently, Prof. Gelovani serves as an Advisor to the Provost at UAEU