[Definition of the T parameter in nasosinusal neoplasms: a CT-MR comparison]

This study was aimed at investigating the value of CT and MRI in the staging of sinonasal tumors. The authors report 22 cases of sinonasal tumors: 7 squamous cell carcinomas, 4 adenoid-cystic carcinomas, 1 mucoepidermoid carcinoma, 6 adenocarcinomas, 1 esthesioneuroblastoma, 1 osteosarcoma, 1 small-cell sarcoma and finally 1 non-Hodgkin lymphoma. No significant differences were observed between CT and MR staging: 2 T2 and 15 T4 lesions were diagnosed in the maxillary sinuses and 3 stage-II and 1 stage-III lesions in the naso-ethmoidal region. Tumor spread was similar in 20/22 cases: MRI excluded the involvement of maxillary and sphenoid sinuses in 2 cases. CT was superior in the assessment of bone destruction particularly at the base of the skull, but MRI better demonstrated intracranial spread. MRI detailed the intraorbital muscles and, in the infratemporal fossa, the pterygoid muscles better than CT. High agreement was observed between CT and histology in 5/7 cases and between MRI and histology in 6/7 cases undergoing craniofacial resection. Seventeen of 22 cases had low to intermediate signal intensity on T1-weighted, PD and T2-weighted MR images. Signal was hyperintense in 5 cases: 1 adenocarcinoma with mucinous features, 3 adenoid-cystic carcinomas and 1 esthesioneuroblastoma. In agreement with literature data, this study confirms CT as the examination of choice in staging sinonasal tumors: nonetheless, MRI yields valuable information in the cases with tumor spread to the muscles and soft tissues.