Associations Between Cardiovascular Risk Factors and Arterial Spin Labelling Derived Perfusion Parameters

Abstract

AbstractBackgroundDecreased cerebral blood flow (CBF) and deterioration of blood‐brain barrier (BBB) are suggested to be precursor conditions of cognitive impairment. Using a novel multi‐echo‐time arterial spin labelling (ASL) protocol, we examined the time of exchange (Tex) of water across the BBB as a measurement of BBB permeability. We further examined the association of cardiovascular risk factors with Tex in an ongoing cohort study.MethodData (n = 29, mean age: 55.9±6.1years, 69% women) were drawn from Neurological biomarkers of Blood, MRI and Cognition (NEURO‐BMC) study performed at National University of Singapore. NEURO‐BMC is an ongoing prospective cohort study (age: 45‐65 years) on brain changes in a subclinical phase of cognitive impairment. A multi‐echo, Hadamard‐encoded multi‐post‐labelling‐delay pseudo‐continuous ASL (PCASL) protocol was used on a 3T scanner. ExploreASL was used with a modified version of FSL FABBER(4) to quantify cerebral blood flow (CBF), arterial transit time (ATT), and Tex. ASL‐extracted parameters were compared with cardiovascular risk parameters such as blood pressure (BP), BMI and smoking status.ResultHigh systolic and diastolic BP were associated with significantly reduced Tex (Fig 1). Additionally, higher systolic and diastolic BP showed a trend of increased ATT and reduced CBF, though the associations were not statistically significant (Table 1). High BMI had a significant association with increased ATT and reduced CBF. However, no trend was observed between BMI and Tex. Participants who ever smoked were observed to have a reduced Tex and CBF and increased ATT, but statistical significance was only found for CBF (Fig 1).ConclusionIn this pilot study, we showed that BBB‐ASL‐derived parameters ‐ ATT, CBF, and Tex ‐ were associated with BP, BMI, and smoking status. While the sample size for this preliminary analysis was too small to make a definitive conclusion as not all associations were statistically significant, all studied cardiovascular risk factors showed their potential in increasing the risk of BBB deterioration. Further investigation with a larger sample size and other health risk factors to assess these observations is warranted.