Assessment with cranial 18-FDG PET/BT for diagnostic evaluation in patients with dementia or mild cognitive impairment with A neuropsychiatric clinical approach

Alzheimer's disease (AD) and mild cognitive impairment (MCI) are common neuropsychiatric diseases in the geriatric age group. Biomarkers that can be used in early diagnosis to slow down the disease process and stop it if possible are being investigated. In our study, we applied various neuropsychiatric tests to the patients and examined the relationship between the data obtained from the brain 18 FDG PET/CT and their disease and clinical conditions. A total of 44 patients diagnosed with AD and MCI according to the diagnostic criteria published by the American Psychiatric Association's DSM-5 and the National Institute of Aging-Alzheimer's Association(NIA-AA) were included in the study. Mini -Mental State Examination(MMSE), Clinical Dementia Rating Scale(CDR), Montreal Cognitive Assessment Scale(MOCA), Geriatric Depression Scale(GDS), Clock Drawing Test(CDT) were applied to participants and 18-FDG PET/CT were scanned. The regional brain glucose metabolisms obtained were compared with the uptake ratio and z score parameters. In patients with AD, glucose metabolism in the anterior cingulate cortex, inferior parietal cortex and lateral temporal cortex symmetrically was found to be statistically significantly lower than in patients with MCI(p<0,05). The patients with AD in 81,8% posterior cingulate, 72,7% inferior parietal and mesial temporal, 68,1% lateral temporal and precuneal, 63,6% superior parietal and anterior cingulate in cortex; and those with MCI in 59% inferior parietal and posterior cingulate, 45,4% precuneal, 40,9% anterior cingulate, superior parietal and lateral temporal, 36,3% mesial temporal cortex in according to z score points hypometabolism determined. As far as we know, our study is the first study in our society that evaluates 18-FDG PET/CT imaging in MCI and AD as an early diagnosis tool and examines its relationship with detailed neuropsychiatric tests. The results of our study show that 18-FDG PET/CT imaging can be used as an early diagnosis biomarker in patients with AD and MCI, and that MCI can be a guide for AD progression in the preclinical stage. Key Words: Alzheimer's disease, Mild cognitive impairment, 18- FDG PET/CT