Ultrasound-guided retrieval of small foreign objects in subcutaneous tissue.

Abstract

To identify the physical properties of the materials most easily located in subcutaneous tissue through the use of conventional ultrasound. High-resolution real-time sonography was performed by a credentialed sonographer on a chicken breast impregnated with five objects-a metal paper clip, a wooden toothpick, a plastic coffee stirrer, a shard of glass, and an 18-gauge needle. Transducer frequencies ranging from 3.5 to 7.5 MHz with linear, curvilinear, and sector-scanning formats were used. All images were interpreted by a staff attending radiologist with other study authors present. The chicken breast was then subjected to radiography for comparison. Wood yielded the strongest acoustic shadow; plastic had the next-best acoustic shadowing. The 7.5-MHz probe yielded its best resolution at shallow depths, whereas the 5-MHz probe was best at greater depths. We conclude that ultrasonography is an excellent technique for the localization and retrieval of nonradiopaque foreign objects in the superficial subcutaneous tissue. It should be given consideration for use in the removal of nonradiopaque superficial foreign objects when conventional radiographic techniques are not effective.