A multilateral collaboration led by the Barcelonaβeta Brain Research Center (BBRC), the research center of the Pasqual Maragall Foundation, has been able to measure with a new magnetic resonance sequence a decrease in cerebral blood flow in the early stages Alzheimer's disease, before clinical symptoms appear. The project has involved experts in the development of new magnetic resonance sequences, clinical professionals from Hospital del Mar and collaborators who provide cutting-edge biomarkers of Alzheimer's disease.

The team has used a new technique, Time-encoded Arterial Spin Labeling (teASL), to detect Very early changes in cerebral blood flow in study participantsThe results, published in the scientific journal Alzheimer's & Dementia, show that people affected by the disease pathology also show less blood flow in specific areas of the brain during its early stages.

«Until now, available ASL techniques allowed us to measure and compare cerebral blood flow in people with a “single delay time.” This refers to the time it takes for arterial blood to transit from the carotid arteries (where it is “labeled”) to the brain region of interest (known as arterial traffic time)», explains Dr Michalis Kassinopoulos, a postdoctoral researcher at the BBRC and one of the lead authors of the study.

Thanks to a research collaboration with Philips, the BBRC has gained access to a new ASL MRI sequence developed by Leiden University Medical Centre and known as time-encoded ASL (teASL). This is a more sensitive and precise tool that reduces arterial transit time differences in the estimation of cerebral blood flow.. The researchers used teASL to measure cerebral blood flow and investigate its association with amyloid and tau pathology, both implicated in Alzheimer's disease. In addition, the team examined the relationship of cerebral blood flow decreases with cerebrospinal fluid biomarkers related to synaptic dysfunction and neurodegeneration.

For this study, a total of 59 participants were divided into three groups: 24 healthy participants with no cognitive impairment or amyloid protein build-up in the brain (the “control” group); 18 healthy volunteers with no cognitive impairment but with amyloid disease, and 17 patients from the Medical Research Unit of the Hospital del Mar in Barcelona, who are affected by the disease. Of the healthy participants, thirty belong to the Alfa study, promoted by the “la Caixa” Foundation.

The study shows that reduced cerebral blood flow is not only present in people with asymptomatic stages of Alzheimer's, but also in people experiencing cognitive decline with beta-amyloid pathology.