Quantitative multiparametric MRI of ovarian cancer

Abstract

Purpose To identify parameters associated with ovarian malignancy using multiparametric quantitative magnetic resonance imaging (MRI). Materials and Methods After Institutional Review Board (IRB) approval, women with ovarian masses underwent preoperative imaging with 3 T MRI. Dynamic contrast‐enhanced (DCE)‐MRI with pharmacokinetic modeling, quantitative T₂ mapping, and diffusion‐weighted imaging with quantitative mapping of the water diffusion parameters were performed. Ovarian masses had one or more discreet regions of interest, categorized as cystic or solid, and histologically diagnosed as benign or malignant. Mean region of interest (ROI) values were compared between benign and malignant masses using generalized estimating equations. In addition, we compared classification accuracy for the mean ROI value to a combination of histogram characteristics (standard deviation, skewness, and kurtosis) from T₂ map ROIs using logistic regression and ROC curve. The significance level was P = 0.05. Results Several DCE‐MRI parameters differentiated solid benign from malignant masses. Toft's rate constant (k_ep) was significantly higher in malignant masses (P < 0.001), as well as quantitative T₂ values (P = 0.003), and signal intensity on T₂ weighted imaging (P = 0.008). A linear combination of the mean, standard deviation, skewness, and kurtosis of T₂ within solid regions (area under the curve [AUC] 0.90) provided better classification accuracy than the mean of T₂ alone (AUC 0.81). Conclusion Quantitative parameters from DCE‐MRI and T₂ mapping can differentiate benign from malignant ovarian masses. J. Magn. Reson. Imaging 2013;38:1501–1509.