Related Experiment Video
Updated: Jul 14, 2026
Evaluating Targeting Accuracy in the Focal Plane for an Ultrasound-guided High-intensity Focused Ultrasound Phased-array System
Published on: March 6, 2019
Improving the Performance Time and Accuracy of Ultrasound-Guided Interventions: A Randomized Controlled Double-Blind
John W Norbury1, Natalie C Karr1, Vivek Sindhi1
1Department of Physical Medicine and Rehabilitation, Brody School of Medicine at East Carolina University, Greenville, North Carolina, USA.
Objectives:
To determine whether the line-of-sight approach improved the performance time and accuracy of ultrasound (US)-guided needle placement targeting the subdeltoid bursa in a cadaver among novice operators compared to the side approach. A secondary objective was to determine whether participants thought the APPLES (angle, position, perpendicular, line up, entry, sweep) mnemonic was a helpful guide for performing the procedure.
Methods:
Medical students and residents were randomized into either a line-of-sight or side approach group and then crossed over to the other group. The procedure time was determined by 2 blinded reviewers. A survey was administered to determine which method participants preferred and whether they thought the APPLES mnemonic was helpful. A paired t test was used to compare the performance time, and the McNemar test was used to compare the accuracy of the methods.
Results:
Among the 110 participants, the performance time with the line-of-sight approach (mean, 14.4 seconds; SD, 9.95 seconds) was significantly decreased compared to the side approach (mean, 18.6 seconds; SD, 10.1 seconds; P = .00029). Additionally, participants who only hit the target using one method were more likely to hit the target in 30 seconds using the line-of-sight approach (P = .035). In total, 72.7% of participants preferred the line-of-sight approach over the side approach, and 88.2% of participants thought that APPLES mnemonic was useful.
Conclusions:
This study highlights the finding that positioning of the operator is important in performing US-guided interventions, and the line-of-sight approach may improve the performance time and accuracy among novice operators. Furthermore, the APPLES mnemonic serves as a useful educational tool for teaching US-guided interventional procedures.
