Reliability of a Novel Ultrasound Transducer Holder for Flow‐Mediated Dilation

Abstract

BackgroundFlow‐mediated dilation (FMD) is the most common test to evaluate endothelial function. Although efforts have been made to incorporate FMD in clinical settings, guidelines still do not advocate for its use because the wide variability on results among testers. Strategies to overcome this problematic scenario include the use of transducer holders to increase the reproducibility on image acquisition. Therefore, the purpose of this study was to test the reliability of a novel ultrasound (US) transducer holder for brachial FMD.MethodsUsing 3D printing technology, an arm US transducer holder was created to assist the assessment of the vasculature via US imaging during FMD. A total of 15 young healthy subjects were evaluated for Intrarater and Interrater FMD reliability. Statistical analysis included Coefficient of Variation (CV) and Intraclass Correlation Coefficient (ICC). Based on the CV, reproducibility was categorized as excellent (0–10%), good (10–20%), moderate (20–30%), or poor (>30%). Regarding ICC, reproducibility was catalogued as poor (>0.5), moderate (0.5–0.75), good (0.75–0.9), and excellent (>0.90).ResultsThe baseline and peak after deflation artery diameter images were analyzed using an automatic edge detection software. The following data was collected:The results in table 1 show that the degree of reliability for an arm US transducer holder during FMD, between and within raters using artery diameter, %FMD, and delta‐FMD as markers, is excellent. The CV for all categories within the inter‐ and intrarater were under 7%, which supports achieving inter‐ and intrarater reliability. The ICC for all categories, with the exception of one, was 90% or better, this shows that the reproducibility of the holder was catalogued as excellent. The Interrater ICC for one category, delta‐FMD, was rated good at 0.89.ConclusionExcellent reliability was achieved with interrater and intrarater FMD using the arm US transducer holder device. This holder has the ability to improve the results of this type of noninvasive endothelial function testing. Analyzed data collected during FMD Reliability Test Baseline Artery Diameter Peak Artery Diameter %FMD Delta‐FMD Intrarater CV (%) 0.26 (0.39) 0.40 (0.42) 6.44 (6.1) 6.27 (6.09) Interrater CV (%) 0.23 (0.16) 0.52 (0.38) 5.75 (5.29) 5.82 (5.39) Intrarater ICC 0.99 0.99 0.97 0.95 Interrater ICC 0.97 0.96 0.97 0.89