In this study, we investigated the relationship of cerebral tau deposition (18F-tau-AD-ML 104 PET/CT) with glucose metabolism (18F-FDG PET/CT) and cognitive function in patients with Alzheimer disease (AD).
Seventy subjects (Mini Mental State Examination [MMSE] score <18 = 37 [AD]; MMSE score, 18–24 = 16 [early AD]) and 17 controls were included in this study. All participants underwent detailed neurological and neuropsychological evaluation, followed by 18F-tau-AD-ML 104 and 18F-FDG PET/CT imaging. Region-wise SUVmax ratios at 50 to 60 minutes postinjection were calculated for 18F-tau-AD-ML 104 and 18F-FDG, using the cerebellar cortex as the reference region. Linear models were used to investigate the association of regional 18F-tau-AD-ML 104 retention with 18F-FDG uptake and cognition (MMSE scores).
18F-Tau-AD-ML 104 retention was observed in the parietal lobe, temporal lobe, hippocampus, parahippocampus, frontal lobe, anterior and posterior cingulate, and precuneus in advanced and early AD patient as compared with normal controls with regional hypometabolism in overlapping regions on 18F-FDG PET. Significant negative association was found between 18F-tau-AD-ML 104 regional retention and glucose metabolism in the parietal lobe, temporal lobe, hippocampus, parahippocampus, frontal lobe, anterior and posterior cingulate, and precuneus among patients with advanced and early AD. In advanced and early AD patients, a negative association was found between 18F-tau-AD-ML 104 regional retention (precuneus) and cognition (MMSE score), whereas a positive association was observed between 18F-FDG regional uptake (precuneus) and cognition (MMSE score).
Tau pathology overlapped with areas of hypometabolism on FDG PET in the brains of AD patients. Tau deposition was found to have negative association with cognitive scores in these patients.
From the Departments of *Nuclear Medicine
†Geriatrics, All India Institute of Medical Sciences, New Delhi, India.
Received for publication May 1, 2019; revision accepted July 22, 2019.
Conflicts of interest and sources of funding: none declared.
Correspondence to: Madhavi Tripathi, MD, DNB, Department of Nuclear Medicine, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India. E-mail: firstname.lastname@example.org.