POCUS Standoff: Comparing Ultrasound Interfaces for Soft Tissue Foreign Body Imaging

Area of Science:

• Emergency Medicine
• Medical Imaging
• Ultrasound Technology

Background:

• Point-of-care ultrasound (POCUS) is valuable for identifying soft tissue foreign bodies (FBs).
• Imaging interfaces like standoff pads and water baths enhance ultrasound resolution for superficial structures.
• Optimal interface selection is crucial for accurate FB detection.

Purpose of the Study:

• To determine the optimal ultrasound imaging interface for detecting foreign bodies in soft tissue.
• To compare the accuracy and image quality of different interfaces, hypothesizing water baths would be superior.

Main Methods:

• Prospective analysis of four ultrasound imaging interfaces: gel, saline bag standoff, water bath, and a novel water-filled patient belongings bag (PBB).
• 18 emergency physicians in training imaged standardized foreign bodies (wood, plastic, metal) in porcine models.
• Primary outcome: accuracy of FB detection; secondary outcomes: detection time, image quality, and impact of training level.

Main Results:

• A trend of greatest accuracy was observed for PBB, followed by water bath, gel, and saline bag.
• Gel ultrasound was significantly more accurate than saline bag (P=0.0120).
• Increased training level correlated with decreased detection time (P=0.02) and increased accuracy, with fellows outperforming residents and interns.

Conclusions:

• Water-filled patient belongings bags (PBBs) present a viable alternative interface for soft tissue foreign body detection.
• PBBs, water baths, and gel interfaces should be considered over saline standoffs for improved foreign body identification.