TITLE:
Optimization of ultrasound assessments of arterial function
AUTHORS:
Lee Stoner, Cary West, Danielle Morozewicz Cates, Joanna M. Young
KEYWORDS:
Ultrasound; Reproducibility; Diameters; Distension; Arterial Stiffness
JOURNAL NAME:
Open Journal of Clinical Diagnostics,
Vol.1 No.3,
December
9,
2011
ABSTRACT: Ultrasound technology is widely used to make assessments of arterial function. The delicate nature of these measurements requires that sources of errors are limited. Therefore, the aim of this study was to assess variability due to probe selection and optimization settings. Methods: Ten healthy 20 - 26 year old male and female subjects were tested. Brachial artery size (diameter) was measured thirty times a second using a B-mode Ultrasound unit equipped with a high-resolution video capture device. Distension was calculated using systolic and diastolic diameters. To assess intersession variability, we made recordings over twelve minutes; with the probe being removed and re-positioned every four minutes. To assess variability due to probe selection and optimization, we manipulated four parameters: 1) Probe selection (7 - 13 MHz, 5 - 10 MHz, 6 - 9 MHz). 2) Probe frequency (11 MHZ, 9.6 MHZ, 8 MHz). 3) Measurement location (near, center or middle field). And, 4) Image mode (B-mode, duplex-mode). To assess inter-session variability, three sets of recordings were made for each probe selection and optimization setting. Results: Mean diameter ICC’s for inter-session variability, probe frequency, measurement location, image display size, and probe selection were 0.99, 0.98, 0.97, 0.99, and 0.90 respectively. Distension ICC’s for intersession variability, probe frequency, measurement location, image display size, and probe selection were 0.66, 0.26, 0.62, 0.60, and 0.51 respectively. Conclusions: Altering probe selection increases measurement variability to the greatest extent. However, as long as probe selection and optimization settings are kept constant, our inter-session variability shows that reliable measurements can be made.