CT, MR, 18 F-FDG PET/CT, and their combined use for the assessment of mandibular invasion by squamous cell carcinomas of the oral cavity
AbstractBackground: A reliable assessment of mandibular invasion is crucial for treatment planning to obtain both radical tumor resection and good functional results. Purpose: To retrospectively compare the diagnostic value of three different imaging methods – computed tomography (CT), magnetic resonance (MR) imaging, 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT – and their combined use for detection of mandibular invasion by squamous cell carcinoma (SCC) of the oral cavity. Material and Methods: Forty-six patients (39 men and 7 women; mean age, 59.4 years) suspected of having mandibular invasion by SCC of the oral cavity underwent CT, MR, and PET/CT within 2 weeks before surgery. First, each study was reviewed separately for the presence of mandibular invasion by tumors. Then, the value of combined images was assessed based on a confidence rating score for each modality assigned by observers. These results were verified with histopathologic findings. Results: Histopathologic examination revealed mandibular invasion in 12 of 46 SCCs. The sensitivity, specificity, and accuracy were 41.7%, 100%, and 84.8% for CT; 58.3%, 97.1%, and 87.0% for MR; and 58.3%, 97.1%, and 87.0% for PET/CT, respectively. The comparison of these modalities showed no statistically significant difference among them ( P > 0.05). The combination of CT, MR, and PET/CT improved sensitivity (83.3%), without loss of specificity (100%) and accuracy (95.7%), although the difference failed to reach statistical significance ( P > 0.05). Conclusion: The combined analysis of CT, MR, and PET/CT can improve sensitivity in the detection of mandibular invasion by SCC of the oral cavity.