Quantifying superficial vein morphology with near-infrared imaging during venous congestion

The venous system plays a key role in clinical practice but remains underassessed due to the limited accessibility of conventional imaging tools. Near-infrared reflection illumination (NIRI) devices ("vein finders"), though recently introduced to assist venipuncture, have potential for broader vascular assessment. Our aim was to investigate the feasibility of a NIRI device to quantify the morphology of superficial hand veins and evaluate their response to a transient hemodynamic stress induced by suprasystolic limb occlusion. The dorsal hand veins of 14 healthy adults (21.5 ± 4.2 y.o.) were continuously recorded during a procedure consisting of a 5 min baseline, 3 min arm occlusion (200 mmHg), and 3 min recovery phases. Morphological parameters including vein width, branching angles, asymmetry indices, junctional exponent deviation, and optimality ratio, were extracted from three metacarpal veins and their tributaries. Nonparametric statistics were used to compare parameters between phases (p < .05). Occlusion led to a significant increase in the width of both receiving and tributary veins (p < .001), reflecting venous pooling. However, branching geometry remained largely unchanged, suggesting structural resilience. Junctional exponent deviation remained low, in agreement with Murray's law. Near-infrared vein finders enable real-time, non-invasive assessment of superficial venous morphology and compliance. Their sensitivity to dynamic vascular changes, combined with potential for integration with automated analysis tools, supports their broader use in vascular diagnostics, preoperative planning, and bedside monitoring.