Comparison of Computed Tomography, Magnetic Resonance Imaging, and Positron Emission Tomography and Computed Tomography for the Evaluation Bone Invasion in Upper and Lower Gingival Cancers.

Purpose: Preoperative detection of bone invasion is important in cases of gingival cancer. The aim of this study was to compare the diagnostic value of 3 imaging methods for the detection of bone invasion in upper and lower gingival cancer: computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) and CT.

Materials And Methods: This retrospective cohort study enrolled patients who underwent a maxillectomy or a mandibulectomy for gingival cancer. Each preoperative image (CT, MRI, or PET/CT) was reviewed for the presence of bone invasion, and the possibility for bone invasion was graded. These results were verified with pathology reports. Sensitivity, specificity, positive predictive value, and negative predictive value for the detection of mandibular involvement in alveolar bone were calculated, and a receiver operating characteristics (ROC) curve analysis was performed.

Results: Forty patients (27 men and 13 women) were enrolled. Pathologic examination disclosed bone invasion in 25 of the 40 patients. Of these patients, 13 had maxillary and 12 had mandibular alveolus involvement. The diagnostic accuracy of CT (90.0%) was highest among the 3 modalities for the detection of bone invasion. In the ROC curve analysis, values for the area under the curve for upper gingival cancer were lower than those for lower gingival cancer.

Conclusions: The 3 imaging methods were less sensitive for the detection of bone invasion in upper gingival cancer than in lower gingival cancer. Cases of upper gingival cancer should be evaluated more carefully for bone invasion before surgery.