An automated optical flow-mediated dilation method for fast screening of endothelial function

Flow-mediated dilation (FMD) is the non-invasive gold standard for assessing endothelial dysfunction, an early and reversible marker of atherosclerosis, yet its uptake is limited by the cost, complexity, and operator dependence of ultrasound. This study presents an optical method that quantifies endothelial dysfunction using a compact, low-cost, fully automated diffuse speckle pulsatile flowmetry (DSPF) device. The system offers a new Reactive-Hyperemia–Flow-Volume (RHFV) index that achieves a strong correlation (r = 0.87) with clinical ultrasound FMD index and high discriminative performance for endothelial dysfunction (AUC = 0.8475), demonstrating accuracy comparable to Doppler ultrasound. By enabling convenient, reliable evaluation of endothelial dysfunction at the point of care, this optical technology holds substantial promise as a primary-care screening tool for cardiovascular risk stratification and longitudinal monitoring, with the potential to improve prevention pathways and broaden access to vascular health assessment. Trial registration: NHG DSRB, 2022/00223. Registered 28 April 2022.