Dentomaxillofacial Radiology, Vol 28, Issue 6 351-356, Copyright © 1999 by British Institute of Radiology

ARTICLES

Detection of bone invasion by gingival carcinoma of the mandible: a comparison of intraoral and panoramic radiography and computed tomography

E. Nakayama, K. Yoshiura, K. Yuasa, O. Tabata, K. Araki, S. Kanda, S. Ozeki and M. Shinohara
Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Kyushu University, Fukuoka, Japan.

OBJECTIVE: To assess the diagnostic accuracy of panoramic radiography (PR), panoramic radiography combined with intraoral radiography (PR+IR), and CT in detecting the supero-inferior extent of tumor invasion of the mandible by gingival carcinoma. METHOD: PR, PR+IR, and CT images of the mandible in 37 patients with gingival carcinoma were evaluated by five oral radiologists for the supero-inferior extent of bone invasion using ROC analysis. The mean ROC curve area (Az) of each observer for the different imaging modalities was analysed by nonparametric two-way ANOVA. P<0.05 was considered statistically significant. RESULTS: The mean Az for the detection of bone invasion were 0.88+/-0.03 for PR, 0.77+/-0.12 for PR+IR, and 0.87+/-0.03 for CT (P=0.0907). The mean Az for the detection of bone invasion beyond the alveolus was 0.89+/-0.07 for PR, 0.85+/-0.08 for PR+IR, and 0.83+/-0.06 for CT (P=0.5438). The mean Az for the detection of bone invasion beneath the mandibular canal were 0.94+/-0.04 for PR, 0.94+/-0.02 for PR+IR, and 0.91+/-0. 04 for CT (P=0.2466). No statistically significant differences were observed in Az between PR, PR+IR, and CT. CONCLUSION: We consider that PR+IR should be adopted as the initial imaging modality to determine the extent of supero-inferior invasion of the mandible in gingival carcinoma.