Whole-tumor MRI histogram analyses of hepatocellular carcinoma: Correlations with Ki-67 labeling index.

PurposeTo evaluate whether whole-tumor histogram-derived parameters for an apparent diffusion coefficient (ADC) map and contrast-enhanced magnetic resonance imaging (MRI) could aid in assessing Ki-67 labeling index (LI) of hepatocellular carcinoma (HCC). Materials and MethodsIn all, 57 patients with HCC who underwent pretreatment MRI with a 3T MR scanner were included retrospectively. Histogram parameters including mean, median, standard deviation, skewness, kurtosis, and percentiles (5(th), 25(th), 75(th), 95(th)) were derived from the ADC map and MR enhancement. Correlations between histogram parameters and Ki-67 LI were evaluated and differences between low Ki-67 (10%) and high Ki-67 (>10%) groups were assessed. ResultsMean, median, 5(th), 25(th), 75(th) percentiles of ADC, and mean, median, 25(th), 75(th), 95(th) percentiles of enhancement of arterial phase (AP) demonstrated significant inverse correlations with Ki-67 LI (rho up to -0.48 for ADC, -0.43 for AP) and showed significant differences between low and high Ki-67 groups (P < 0.001-0.04). Areas under the receiver operator characteristics (ROC) curve for identification of high Ki-67 were 0.78, 0.77, 0.79, 0.82, and 0.76 for mean, median, 5(th), 25(th), 75(th) percentiles of ADC, respectively, and 0.74, 0.81, 0.76, 0.82, 0.69 for mean, median, 25(th), 75(th), 95(th) percentiles of AP, respectively. ConclusionHistogram-derived parameters of ADC and AP were potentially helpful for predicting Ki-67 LI of HCC. Level of Evidence:3 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:383-392