What's in your mouth? The CT appearance of comestible intraoral foreign bodies

Abstract

BACKGROUND AND PURPOSE: Comestible or chewable intraoral foreign bodies (IOFB), such as candies, gum, and chewing tobacco, are seen incidentally on many CT scans of the head and neck. If these foreign bodies are misinterpreted as pathology, patients may be subjected to unnecessary distress or unneeded radiation from additional imaging. The purpose of this study was to characterize the CT appearance of comestible IOFBs and to find characteristics that distinguish them from true pathology. MATERIALS AND METHODS: With institutional review board approval, 30 patients who were already scheduled to undergo CT examinations of the head and neck were enrolled in this study. Nine typical IOFBs with different physical characteristics were selected for inclusion. Each patient placed 1 IOFB in his or her mouth before the initiation of the routine clinical scan. The resulting scans were evaluated by 2 head and neck radiologists. In vivo and ex vivo attenuation measurements were obtained for each IOFB. RESULTS: The attenuation of comestible IOFBs ranged from 184 to 475 Hounsfield units. Large, hard IOFBs were most easily distinguished from mucosal lesions, but might be mistaken for odontogenic or bone tumors. Small, hard IOFBs could be mistaken for calculi, tooth fragments, or enhancing vessels. Soft IOFBs generally had more confusing configurations and more heterogeneous densities and, thus, might be mistaken for enhancing mucosal lesions. Foci of gas were often identified within chewable IOFBs, mimicking an abscess. Because all of the IOFBs had higher densities than soft tissue, they could all be mistaken for calcified, enhancing, or bony lesions. CONCLUSION: Radiologists frequently encounter IOFBs on CT examinations of the head and neck. Familiarity with the expected appearance of these incidental pseudolesions is important to prevent misdiagnosis as a true pathologic process.