[CT and MRI diagnosis of lesions in unilateral maxillary sinus]

To study the CT and MRI findings of lesions in unilateral maxillary sinus, and to compare the effect of CT and MRI in the differential diagnosis of lesions in unilateral maxillary sinus.

Retrospective analysis of CT and contract-enhanced MRI imaging data from 34 patients with lesions in unilateral maxillary sinus which were diagnosed by endoscopic sinus surgery and postoperative pathology. The CT and contract-enhanced MRI's value in the differential diagnosis in lesions in unilateral maxillary sinus was analysed.

All 34 patients had unilateral maxillary sinus lesions. On CT: soft tissue density shadow in the unilateral maxillary sinus was found in all 34 cases. Five cases showed spot high density with thickening bone in the maxillary sinus wall. Eleven cases showed expansion of the opening of maxillary sinuses. Two cases showed broken lateral wall of nasal cavity . One case showed soft tissue density shadow in the maxillary sinus with curve edge with high density shadow which had a tooth shadow in it. Other 14 cases showed only soft density shadow in the maxillary sinuses. On MRI: all 34 cases revealed lower signals on T1WI compared to gray matter. Little loss signal were found in the inner of the maxillary sinus fungal balls on T1WI. Enhanced MR imaging showed no enhanced in nasal sinusitis, sinus cysts and polyp of posterior naris. In homogenous enhancing and "the cerebral convolution sign" were found in the hemorrhagic and necrotic nasal polyp, the nasal inverted papilloma and the malignant tumor cases. Higher signals were seen in the nasal sinusitis, fungal balls and the polyp of posterior naris cases on T2WI. In homogenous signal with different levels were found in the hemorrhagic and necrotic nasal polyp, the nasal inverted papilloma and the malignant tumor cases on T2WI.

CT and MRI examination are important in the diagnosis of the unilateral maxillary sinus lesions. Both CT and MRI had more differential diagnostic value in the unilateral maxillary sinus lesions than only CT used.