Pulse wave velocity measurement assessing the superficial carotid–femoral distance via smartphone-based light detection and ranging

Carotid-femoral pulse wave velocity (cfPWV) is the gold standard for non-invasive assessment of aortic stiffness. Tape measurement of the carotid-femoral distance typically requires an assistant to hold the tape while the operator maintains the Doller transducer position. This study assessed the concordance and intra-observer reliability of distance measurements obtained via smartphone-based light detection and ranging (LiDAR) technology compared with traditional tape measurement. A cohort of 46 adult participants (mean age, 50.0±12.7 years) underwent Doppler ultrasound evaluation to determine carotid and femoral pulse transit times. The operator measured the superficial carotid-femoral distance using tape and smartphone LiDAR in alternating sequences. Duplicate measurements were taken following a washout period to evaluate intra-observer reliability. LiDAR distance measurements strongly agreed with tape measurements (ICC (2,1) = 0.92, 95% CI 0.81-0.97; mean bias <0.01 m). The resulting cfPWV calculations demonstrated good agreement (ICC (2,1) = 0.94, 95% CI 0.86-0.98; mean bias, 0.03 m/s). Both modalities exhibited high intra-observer reliability (tape ICC (3,1) = 0.98; LiDAR ICC (3,1) = 0.99). The diagnostic classification for elevated cfPWV (> 10 m/s) showed near-perfect concordance between the methods (kappa > 0.98). Smartphone-based LiDAR telemetry provides distance measurements and cfPWV estimates that are highly concordant with traditional tape measurements, offering a reliable single-operator alternative for superficial distance acquisition. While these findings confirm technical equivalence and intra-observer reliability, further studies incorporating reference standards and quantitative time-motion analyses are required to confirm the clinical workflow advantages of this method.