Evaluation of Computed Tomography and Magnetic Resonance Imaging of Sinonasal Inverted Papilloma

Bai, Chang Hoon; Seo, Young Jung; Lee, Seok Choon; Chen, Seung Min; Baek, Un Hoi; Jung, Eun Chae; Song, Si Youn; Kim, Yong Dae

Abstract

BACKGROUND
Computed tomography (CT) is commonly used to evaluate the degree of sinus involvement in cases of inverted papilloma (IP). However, CT cannot differentiate tumor from adjacent inflammatory mucosa or retained secretions. By contrast, magnetic resonance imaging (MRI) has been reported to be useful in distinguishing IP from paranasal sinusitis. This study investigated whether preoperative assessment with MRI and CT accurately predict the extent of IP. MATERIALS AND METHODS: CT and MRI were retrospectively reviewed in 9 cases of IP. Patients were categorized into stages based on CT and MRI findings, according to the staging system proposed by Krouse. The involvement of IP in each sinus was also assessed. RESULTS: Differentiation of IP from inflammatory disease may be more successful in routine cases where the inflammatory mucosa has low signal intensity on T1-weighted images and very high signal intensity on T2-weighted images. CT imaging could not differentiate tumor from adjacent inflammatory mucosa or retained secretions. CONCLUSION: Preoperative MRI of IP can predict the location and extent of the tumor involvement in the paranasal sinuses and sometimes predicts malignant changes.