Comparing the Accuracy of Micro-Focus X-ray Technology to Standard Clinical Ultrasound for Locating Small Glass Foreign Bodies in Soft Tissue

Abstract

Foreign bodies are found in as many as 15% of traumatic wounds. Point of Care ultrasound (POCUS) is now considered reliable for detecting FBs in wounds. Unfortunately, up to 38% of these FBs are initially missed, resulting in infections, delayed wound healing, and loss of function. Microfocus X-ray imaging (MFXI) has a significantly higher resolution (up to 100×) than conventional X-ray imaging. Therefore, it can potentially be used for Point of Care diagnostics. Up to seven glass fragments smaller than 2.5 mm were embedded in each of the 58 chicken wings and thighs. Two control samples were prepared with no glass fragments. Five emergency medicine physicians with ultrasound training imaged the samples with a Butterfly iQ+ at 1 to 10 MHz center frequencies and counted the glass pieces. This device is an example of handheld PCUS equipment that is particularly valuable in resource-limited areas and austere settings where portability is a significant factor. The same five physicians counted the number of foreign bodies in each X-ray image. The physicians were not trained to read micro-focus X-ray images but had read standard X-rays regularly as part of their medical practice and had at least 3 years of hands-on clinical practice using POCUS. Across physicians and samples, raters correctly identified an average of 97.6% of FBs using MFXI (96.5% interrater reliability) and 62.3% of FBs using POCUS (70.8% interrater reliability).