Visually-induced hemodynamic response and white matter hyperintensities in middle-aged women with ischemic stroke or...

BackgroundMigraine, especially with aura (MA), increases the risk of brain white matter hyperintensities (WMH) and ischemic stroke. Altered microvascular function has been proposed as a shared underlying mechanism, potentially involving endothelial dysfunction. Visually-induced hemodynamic response describes the process by which cerebral blood flow is locally increased to meet the metabolic demands of neuronal activity and may serve as a surrogate measure of cerebral endothelial function. We investigated the relationship between visually-induced hemodynamic responseand WMH volume in middle-aged women with ischemic stroke or MA.MethodsWe cross-sectionally measured hemodynamic response using blood-oxygen-level-dependent (BOLD) fMRI upon visual stimulation on 7T-MRI, and WMH volume on 3T-MRI, in three groups of women aged 40-60 with: (I)ischemic stroke, (II)MA, and (III)no history of stroke or migraine. We assessed the associations between BOLD parameters in the posterior circulation (amplitude, time-to-peak [TTP], and time-to-baseline [TTB]) and WMH volume using multivariable linear regression within each group.ResultsWe included 87 women (mean age 51 years): (I)25 with ischemic stroke, (II)25 with MA, and (III)37 without stroke or migraine. Visually-induced hemodynamic response was similar across groups and not associated with WMH volume overall. However, lower amplitude was associated with higher deep WMH volume in those without stroke or migraine (adjusted-β= -0.28;95%CI = -0.53 to -0.02 mL), shorter TTB with greater periventricular WMH volume in women with MA (adjusted-β= -0.12;95%CI = -0.21 to -0.02 mL), and longer TTP with increased periventricular WMH volume in women with stroke (adjusted-β=0.22;95%CI = 0.06 to 0.40 mL).ConclusionsNo overall association was observed between visually-induced hemodynamic response and WMH volume. Exploratory findings suggest potential differences in hemodynamic response in the posterior circulation across groups, which require replication in larger datasets and confirmation in longitudinal studies to clarify their temporal or mechanistic relevance to WMH development.