Comparative evaluation of soft-tissue foreign body detection using ultrasound and radiography: a phantom study

Soft-tissue foreign bodies (STFBs) are common clinical presentations requiring accurate imaging for effective diagnosis and management. This experimental phantom study compared the performance of ultrasound and general radiography in detecting STFBs of various materials and depths using anatomically relevant cow-foreleg models. Eight foreign bodies; metallic, organic, and inorganic were inserted at depths of 1, 3, and 5 cm. Image visibility was assessed by two radiologists using standardized scoring criteria, with substantial inter-rater agreement (weighted Cohen’s κ = 0.74). Ultrasound yielded significantly higher visibility scores than radiography, as confirmed by a Wilcoxon signed-rank test (Z = −2.82, p = .01). A Friedman test showed no significant depth-related differences in ultrasound image quality (χ² (2) = 0.57, p = .75). Radiographic detection also remained consistent across depths (χ² (2) = 4.00, p = .14), although it was notably influenced by the radiopacity of the foreign body materials. Overall, the findings support existing evidence that ultrasound provides superior diagnostic performance, particularly when the composition of the suspected foreign body is unknown. This study reinforces the potential role of ultrasound as a first-line imaging modality for suspected STFBs.