RESUMEN
PURPOSE: The purpose of this study is to compare the value of CT and SPECT in diagnosis of lower gingival carcinoma invading the mandible. METHODS: From February 2002 to October 2006, twenty-one patients with lower gingival squamous cell carcinoma were enrolled.The data of CT and SPECT were studied,and compared with histopathological findings. RESULTS: Among the 21 patients,the sensitivity, accuracy, negative predictive value and Youden's index of SPECT were 100.00%, 95.24%, 100.00% and 1.00,respectively. While the sensitivity, accuracy, negative predictive value and Youden's index of CT were 80.00%, 80.95%, 20.00% and 0.80, respectively. There were four false negatives assessments of bone invasion(80.00%) by CT scan, while no false negatives by SPECT. CONCLUSIONS: SPECT is superior to CT, and can be used as a routine screening method to assess lower gingival carcinoma invading the mandible.