Comparison of ultrasonography, magnetic resonance imaging and cone beam computed tomography for detection of foreign bodies in maxillofacial region

Abstract

Introduction: Foreign Bodies (FBs) entrapped in the maxillofacial region have a high prevalence due to trauma and accidents. Accurate localization of FBs and verifying their type and size are critical to assist the surgeon in their fast retrieval with minimal tissue damage. Aim: To assess and compare the imaging modalities including MRI, ultrasonography and Cone Beam Computed Tomography (CBCT) for detection of different types of FBs. Materials and Methods: In this study, four types of FBs including pieces of normal glass, barium glass, wood and pebbles with equal sizes were placed randomly in two sheep heads in different locations such as upper lip, maxillary sinus and body of mandible as FBs and subjected to MRI, ultrasound and CBCT. The images were interpreted by expert observers and the data was analysed using the stata 11 software, kappa test and chi-square test. Results: Sensitivity of CBCT, MRI and ultrasound for detecting foreign bodies was 79.19%, 20.83% and 33.33%, respectively. None of the imaging modalities could clearly visualize wooden FBs. Among different FBs, pebbles and barium glass were detected more accurately by radiographic imaging technique. The sensitivity of CBCT, ultrasound and MRI for pebbles was 100%, 33.33% and 16.67%, respectively. The sensitivity of CBCT, ultrasound and MRI for barium glass was 100%, 33.33% and 41.69%, respectively. The sensitivity of CBCT, ultrasound and MRI for wood was 33.33%, 33.33% and 16.67%, respectively. Specificity of all three imaging modalities was 100%. Diagnostic accuracy of all three imaging modalities was higher for detection of FBs in the upper lip than those in the body of mandible, and FBs in the latter location had higher detection accuracy than those in the maxillary sinus. Conclusion: Among the three imaging modalities, CBCT had the highest diagnostic sensitivity for the examined FBs. The highest diagnostic sensitivity was noted for pebbles and barium glass.