PET/MRI multimodality imaging to evaluate changes in glymphatic system function and biomarkers of Alzheimer’s disease

• Published in: Scientific reports 2024-05, Vol.14 (1), p.12310-8, Article 12310
• Main Authors: Okazawa, Hidehiko, Nogami, Munenobu, Ishida, Shota, Makino, Akira, Mori, Tetsuya, Kiyono, Yasushi, Ikawa, Masamichi
• Format: Article
• Language: English
• Subjects: 631/378/340; 692/617/375/132/1283; Accumulation; Aged; Aged, 80 and over; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - metabolism; Alzheimer's disease; Amyloid imaging; Aniline Compounds; Biomarkers; Biomarkers - metabolism; Brain - diagnostic imaging; Brain - metabolism; Cognitive ability; Cognitive Dysfunction - diagnostic imaging; Cognitive Dysfunction - metabolism; Diffusion Tensor Imaging - methods; Disease; DTI-ALPS; Female; Glymphatic system; Glymphatic System - diagnostic imaging; Glymphatic System - metabolism; Hippocampus; Humanities and Social Sciences; Humans; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Middle Aged; multidisciplinary; Multimodal Imaging - methods; Neurodegenerative diseases; Neuroimaging; PET/MRI; Positron emission tomography; Positron-Emission Tomography - methods; Science; Science (multidisciplinary); Thiazoles
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-62806-5

The glymphatic system is considered to play a pivotal role in the clearance of disease-causing proteins in neurodegenerative diseases. This study employed MR diffusion tensor imaging (DTI) to evaluate glymphatic system function and its correlation with brain amyloid accumulation levels measured using [ 11 C]Pittsburgh compound-B (PiB) PET/MRI. Fifty-six patients with mild cognitive impairment and early Alzheimer’s disease (AD: 70 ± 11 y) underwent [ 11 C]PiB PET/MRI to assess amyloid deposition and were compared with 27 age-matched cognitively normal volunteers (CN: 69 ± 10y). All participants were evaluated for cognitive function using the Mini Mental State Examination (MMSE) before [ 11 C]PiB PET/MRI. DTI images were acquired during the PET/MRI scan with several other MR sequences. The DTI analysis along the perivascular space index (DTI-ALPS index) was calculated to estimate the functional activity of the glymphatic system. Centiloid scale was applied to quantify amyloid deposition levels from [ 11 C]PiB PET images. All patients in the AD group showed positive [ 11 C]PiB accumulation, whereas all CN participants were negative. ALPS-index for all subjects linearly correlated with PiB centiloid, MMSE scores, and hippocampal volume. The correlation between the ALPS-index and PiB accumulation was more pronounced than with any other biomarkers. These findings suggest that glymphatic system dysfunction is a significant factor in the early stages of Alzheimer’s disease.