Validation and Feasibility of an Automated System for the Assessment of Vascular Structure and Mechanical Properties in the Digital Arteries: An Ultrahigh-Frequency Ultrasound Study

Ultrahigh-frequency ultrasound (UHFUS) allows sharp visualization of human small muscular arteries. This may help in elucidating some aspects of the pathophysiology of arterial aging, such as the stiffness gradient between large and small conduit arteries and its consequences on the microcirculation, as well as vascular diseases affecting medium-sized arteries. However, UHFUS use is still limited, partly because of the lack of validated tools to quantify vascular structure and mechanical properties of small muscular arteries. In this validation study, scans of digital arteries were obtained with UHFUS (VevoMD, Visualsonics-Fujifilm, Toronto, ON, Canada), analyzed using Carotid Studio software (Quipu, Pisa, Italy) and compared with the manual measurement. Agreement between the two techniques on measures of diameter, distension and intima-media thickness (IMT) was evaluated using Bland-Altman analyses; inter- and intra-operator reproducibility was evaluated using coefficients of variation (CVs). Overall, no trend or significant bias was observed between Carotid Studio and manual analysis. All limits of agreement were acceptable. The intra-observer CV of diastolic diameter and IMT were 4.1% and 4.2%, respectively. The inter-observer CV for diastolic diameter and IMT were 7.3% and 5.4%, respectively. Intra- and inter-observer CVs for distension were higher (25.7% and 26.7%, respectively). These results suggest that the Carotid Studio software is a valid and reproducible tool to study UHFUS scans of digital arteries, with potential utility both in rare vascular diseases of medium-sized arteries and in the study of the pathophysiology of arterial aging in general.