Multiparametric MRI in differentiation between sinonasal inverted papilloma and malignant transformation of inverted papilloma

Abstract

Objective To identify the value of multiparametric MR imaging features including diffusion weighted (DW) and dynamic contrast-enhanced (DCE) MR imaging features in differentiation between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region. Methods Seventy-seven patients were included in this study, including 12 malignant transformation of inverted papilloma and 65 inverted papillomas. Conventional MRI including nonenhanced and static contrast-enhanced imaging, DCE-and the DW-MRI were analyzed. Differences in conventional MRI features, ADCs and DCE-MRI parameters between the two entities were determined by Fisher exact test, independent samples t-test and Mann-Whitney U test, respectively. Results There were significant differences in convoluted cerebriform pattern (P=0.045), necrosis (P=0.003) and orbit involvement (P<0.01) between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region. The ADCs of inverted papilloma were significantly lower than those of malignant transformation of inverted papilloma (P<0.01). There were significant differences in time to peak enhancement (P<0.01), maximum contrast index (P=0.004) and time intensity curve types (P<0.01) between the two entities. Conclusions A multiparametric approach using conventional MR imaging with added ADCs and DCE-MRI parameters had the potential to improve the differentiation between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region. Key words: Nasal cavity; Sinus; Neoplasms; Multiparametric MR imaging