Staging of squamous cell carcinoma of the oral cavity and oropharynx: A comparison of MRI and CT in T- and N-staging

Purpose: Our purpose was to assess the accuracy of CT and MRI in staging of squamous cell carcinoma (SCC) of the oral cavity and oropharynx. Method: Fifty-one episodes of primary and recurrent SCC were assessed with CT and MRI. The results were compared with pathological staging. Results: For staging primary tumours, the accuracy of MR was 77% and that o f CT was 67%. For detecting recurrent tumour, the accuracy of MR was 89% an d that of CT was 100%. For N-staging, nodal sites were divided, according t o the site of the primary tumour. into high and low risk. Sensitivity for h igh risk sites was 60% for clinical assessment, 35% for CT, and 75% for MR. Negative predictive value (NPV) was less than or equal to 50% for all meth ods. For low risk sites, the NPV was greater than or equal to 95% for all m ethods. Conclusion: For T-staging, MR scanning is overall more accurate than CT. If degraded images and T1 tumours are excluded, the techniques are comparable . MR scanning is oversensitive for recurrent disease. For N-staging, all me thods failed to detect small metastatic deposits.