Ultrasonography in soft-tissue foreign-body detection: a phantom study

Introduction
Foreign body implantation into the soft tissues, either in the early period or late period, is a common cause of emergency department admissions. Direct X-rays are preferred in the diagnosis of soft-tissue foreign-bodies. Herein, we aimed to analyse the detection rates of foreign bodies of various sizes placed in phantoms implanted into soft tissue by ultrasonography.

Material and methods
A total of 740 pieces of chicken fillet were prepared as phantoms. No objects were implanted into 100 phantoms. We inserted glass, porcelain, plastic, wood, pencil tip, chicken bone, iron, walnut shell, and fishbone with a length of < 1 cm, 1-3 cm, and 3-5 cm into 20 pieces of chicken phantom in each size of foreign body (FB). In addition, 1-3 cm long peanut shell, < 1 cm rose spikes, < 1 cm cactus thorns, < 1 cm pellets, and < 1 cm staples were inserted into 20 pieces of chicken for each object. Each of the chicken pieces was placed inside a latex glove and examined by ultrasonography.

Results
The sensitivity of ultrasonography in the detection of the cactus thorn was 5%, whereas it ranged between 82.5 and 100% for other objects. For glass, plastic, wood, iron, and fishbone, we found that when the size exceeded 1 cm, the sensitivity increased.

Conclusions
In the evaluation of soft tissue FBs, as the size of the FBs increases, the diagnostic value of ultrasonography increases.