Detection of wooden foreign bodies in muscle tissue: experimental comparison of computed tomography, magnetic resonance imaging, and ultrasonography.

An experimental study was performed to compare computed tomography (CT), magnetic resonance imaging (MRI), and real-time, high resolution ultrasonography (US) for the detection of wooden foreign bodies in muscle tissue. Wooden splinters were prepared, measured for size, soaked in saline, and placed in porcine muscle distant from and adjacent to bone. The specimens were then examined using roentgenography, CT and MRI in planes parallel and perpendicular to the splinters, and US. The largest wooden foreign bodies (minimum smallest width = 10 mm) were easily detected by CT, MRI, and US. Almost all splinters of various sizes, small and large, soaked in saline for 5 months were easily detected by MRI. Smaller splinters (minimum smallest width = 1-4 mm) soaked for only 3 days and placed distant from bone were most easily detected by US; those soaked for 5 months were most easily detected by either US or MRI. The smaller splinters soaked for only 3 days and placed near bone were not reliably detected by any of the imaging methods; CT and MRI were both more sensitive than US in this situation. MRI scanning was more sensitive perpendicular than parallel to the long axis of the splinters. Therefore, either US or MRI may be the best initial imaging modality for evaluation of a suspected wooden foreign body, depending on availability of imaging method, chronicity of symptoms, and proximity to bone.