Blood‐brain barrier disruption measured by dynamic contrast‐enhanced MRI in Alzheimer’s disease

Background Alzheimer’s disease (AD) is characterized by the accumulation of amyloid beta (Aß) plaques in the brain. Blood‐brain barrier (BBB) dysfunction has been associated with AD. Aß‐plaques have been found to disrupt the BBB, leading to increased permeability and invasion of immune cells into the CNS and triggering an inflammatory response, and contributing to neurodegeneration. In this study, we investigated BBB disruption in Alzheimer’s disease and its associations with amyloid deposition and clinical severity, and cognitive decline. Method In this cross‐sectional study, n = 16 AD patients were included. AD patients were defined as amyloid positive by CSF amyloid‐ß42/amyloid‐ß40 ratio < 5,5% and a Mini‐Mental‐State Examination (MMSE) score < 27. Dynamic contrast‐enhanced magnetic resonance imaging (DCE MRI), a non‐invasive imaging technique that uses intravenously injected gadolinium to quantify the permeability of the BBB has been acquired. DCE‐MRI quantification was quantified using the Patlak method. To analyse the regional degree of BBB disruption the AAL atlas was warped onto the Patlak maps and the median of each ROI was calculated. The cortical amyloid deposition has been quantified using 18F]flutemetamol ß‐amyloid‐PET and cognitive performance was assessed using the Alzheimer’s Disease neuropsychological battery (CERAD‐NB). Associations were tested using linear regression models adjusted for age and sex in SPSS. Result The highest Ktrans values were measured in the orbitofrontal cortex (mean: 1,6×10‐3 min‐1). BBB dysfunction in median Ktrans values in the bilateral temporal lobe and particularly the right hippocampus were associated with decreases in the CSF amyloid‐ß ratio. Furthermore, BBB dysfunction was negatively associated with cognitive decline measured by the CERAD‐NB. BBB dysfunction overlapped with amyloid PET accumulation in the parietal and temporal brain regions. Conclusion DCE MRI shows spatially localized BBB dysfunction in AD. The BBB dysfunction seems to be more severe in regions of the brain that are affected by Aß plaques. This could support the idea that Aß plaque contributes to BBB dysfunction in AD. BBB dysfunction also tends to be pronounced in patients with more severe cognitive impairment, suggesting that it may play a role in the progression of AD.