Imaging modalities for the visualisation of non-metallic foreign bodies.

Abstract

Imaging metallic foreign bodies normally does not cause problems to the radiographers as most are radio-opaque and are therefore visualised with the use of conventional radiography. However when it comes to non-metallic foreign bodies, some problems could arise especially with wood and plastic since they are radiolucent and therefore not visible on plain x-rays. If a good knowledge of the different non-metallic foreign bodies and the imaging modalities available is not achieved, these types of foreign bodies can easily be missed. If so, these can cause reactions in the body, especially wood since it is a porous material. This research project was performed in order to identify the types of nonmetallic foreign bodies (wood, plastic and glass) and to compare the four major imaging modalities for the detection of each non-metallic foreign body. A discussion of the available literature with regards to the four imaging modalities is presented. The imaging modalities discussed are: Plain Radiography, Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Ultrasound (US). In this study, the best imaging modality for the identification and localisation of non-metallic foreign bodies was found to be Ultrasound. The reasons are various and they are discussed in the study. However, each imaging modality can be useful in certain cases, improving the management of the patient. A list of recommendations is also presented on the best use of the modalities.