OBJECTIVE To retrospectively summarize the CT and enhanced MRI imaging characteristics of common unilateral benign nasal and sinus lesions and to outline key points for differentiation from malignant lesions.METHODS A total of 134 cases of unilateral benign nasal and sinus lesions were included in this study,with preoperative sinus CT and enhanced MRI examinations performed.The imaging characteristics of CT and MRI,the extent of the lesions,and the involvement and destruction of surrounding bone and structures were recorded and summarized for each type of lesion.RESULTS Unilateral lesions on CT appeared as generally homogeneous soft tissue density shadows.The affected sinus bones showed internal calcification,localized bone hyperplasia of the sinus wall,extensive uniform centripetal bone hyperplasia and thickening of the sinus wall,expansive destruction of the sinus wall bone,and worm-eaten destruction of the sinus wall bone in 33,13,29,9,and 5 cases,respectively.On MRI T1WI,the lesions appeared as generally homogeneous isointense shadows.Enhanced T1 images showed mild,moderate,and significant enhancement in 3,10,and 108 cases,respectively,with 55 cases presenting as mixed signals.CONCLUSION The imaging manifestations of unilateral benign lesions vary.CT can clearly present high-density shadows such as calcifications within unilateral lesions and changes in surrounding bone.Enhanced MRI of the sinuses provides richer information about the different components within the lesions.Careful differentiation of unilateral lesions should be performed by combining the imaging characteristics of sinus CT and enhanced MRI.