RESUMEN
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.