Effects of position and operator on high-frequency ultrasound scan quality

Abstract

Objectives High-frequency ultrasound may evaluate those at risk for pressure ulcers. Images may be obtained by clinicians with limited training. The prone position is recommended for obtaining sacral scans but may not be feasible in the critically ill. This study investigated image quality using multiple operators and a variety of patient positions. Research Methodology Sacral scans were performed in three randomized positions in 50 volunteers by three different investigators using a 20 MHz ultrasound system. General linear models and ANOVA random effects models were used to examine the effects of operator and position on image quality rating, and measures of dermal thickness, and dermal density. Results The best scan for each position and operator was used for analysis (N=447 images). Image rating varied by operator (p=0.0004), although mean ratings were 3.5 or above for all operators. Dermal thickness was less for the prone position than in 90° or 60° side-lying positions (p=0.0137, p=0.0003). Dermal density was lower for the prone position than for the 90° or 60° positions (p<0.0001 for both). Conclusions These data show that overall scan quality was acceptable in all positions with all operators. However, differences were found between side-lying positions and the prone for dermal thickness and dermal density measures.

High-Frequency Ultrasound: Obtaining Optimal Images and the Effect of Image Artifacts on Image Quality

“…Our previous study evaluated the quality of images obtained by multiple operators in different subject positions (prone, left side-lying with 60 degree rotation, left side-lying with 90 degree rotation) and found that the overall scan quality was similar in all positions with all operators. 22 …”

High-Frequency Ultrasound

“…In our recent study evaluating general HFUS thickness and density measurements between prone, 60 degree, and 90 degree side-lying positions, we found significant differences between thickness and density with respect to position. 16 Specifically layer thickness and density were significantly less for the prone position than either the 90 degree or 60 degree positions. Due to significant differences found with respect to position for thickness and median intensity, we further report LEP:TP ratio for all three positions.…”

“…As is well-known, highest quality scans produce highest quality data although we showed that high quality scans are not always possible. 16 …”

“…Interrater reliability between operators was generally good and results were previously published. 16 The first position was achieved within about 2 minutes of arrival to the bay.…”

“…In our first study regarding the effect of HFUS with respect to position we found that different positions affected quantitative HFUS measurements. 16 We are now describing the relationships fully and reporting a second density measurement currently more widely used in research. It would be useful to fully understand the relationship of position to quantitative parameters obtained by HFUS software as ICU patient position may change frequently and we now know that position affects HFUS data.…”