Diagnostic imaging of tumor invasion of the mandible.

Several imaging techniques, such as conventional radiography, sonography, computed tomography, isotope scanning and magnetic resonance tomography are used for evaluation of malignant tumors in the region of the floor of the mouth and the tongue. At present, conventional radiography, as well as computed tomography and isotope scanning are the techniques preferred for examination of the mandible. In this study, the results of conventional radiographic examination, computed tomography, ultrasound and Tc scanning in detecting tumor invasion of the mandibular bone, are documented and correlated to surgical and histological findings. The results suggest that ultrasound--our primary diagnostic imaging technique for evaluation of tumors of the floor of the mouth and the tongue--not only provides excellent imaging of tumor extension in soft tissue but also allows accurate diagnosis of osteodestructions of the mandible. In most regions ultrasound had the same accuracy in detecting tumor invasion of the mandible. In the alveolar process, however, sonography was superior to other imaging techniques. The lingual surface of the mandibular ramus can not be screened by the extraoral sonography.