The Association of Metabolic Brain MRI, Amyloid PET, and Clinical Factors: A Study of Alzheimer's Disease and Normal Controls From the Open Access Series of Imaging Studies Dataset

Abstract

BackgroundAlthough brain activities in Alzheimer's disease (AD) might be evaluated MRI and PET, the relationships between brain temperature (BT), the index of diffusivity along the perivascular space (ALPS index), and amyloid deposition in the cerebral cortex are still unclear.PurposeTo investigate the relationship between metabolic imaging measurements and clinical information in patients with AD and normal controls (NCs).Study TypeRetrospective analysis of a prospective dataset.Population58 participants (78.3 ± 6.8 years; 30 female): 29 AD patients and 29 age‐ and sex‐matched NCs from the Open Access Series of Imaging Studies dataset.Field Strength/Sequence3T; T1‐weighted magnetization‐prepared rapid gradient‐echo, diffusion tensor imaging with 64 directions, and dynamic 18F‐florbetapir PET.AssessmentImaging metrics were compared between AD and NCs. These included BT calculated by the diffusivity of the lateral ventricles, ALPS index that reflects the glymphatic system, the mean standardized uptake value ratio (SUVR) of amyloid PET in the cerebral cortex and clinical information, such as age, sex, and MMSE.Statistical TestsPearson's or Spearman's correlation and multiple linear regression analyses. P values <0.05 were defined as statistically significant.ResultsSignificant positive correlations were found between BT and ALPS index (r = 0.44 for NCs), while significant negative correlations were found between age and ALPS index (rs = −0.43 for AD and − 0.47 for NCs). The SUVR of amyloid PET was not significantly associated with BT (P = 0.81 for AD and 0.21 for NCs) or ALPS index (P = 0.10 for AD and 0.52 for NCs). In the multiple regression analysis, age was significantly associated with BT, while age, sex, and presence of AD were significantly associated with the ALPS index.Data ConclusionImpairment of the glymphatic system measured using MRI was associated with lower BT and aging.Level of Evidence3Technical Efficacy Stage1