Added Value of Quantitative Apparent Diffusion Coefficients for Identifying Small Hepatocellular Carcinoma from Benign Nodule Categorized as LI-RADS 3 and 4 in Cirrhosis

Background and Aims:Correct identification of small hepa-tocellular carcinomas(HCCs)and benign nodules in cirrhosis remains challenging,quantitative apparent diffusion coeffi-cients(ADCs)have shown potential value in characterization of benign and malignant liver lesions.We aimed to explore the added value of ADCs in the identification of small(≤3 cm)HCCs and benign nodules categorized as Liver Imag-ing Reporting and Data System(LI-RADS)3(LR-3)and 4(LR-4)in cirrhosis.Methods:Ninety-seven cirrhosis patients with 109 small nodules(70 HCCs,39 benign nodules)of LR-3 and 4 LR-4 based on major and ancillary magnetic resonance imaging features were included.Multiparametric quantitative ADCs of the lesions,including the mean ADC(ADCmean),min-imum ADC(ADCmin),maximal ADC(ADCmax),ADC standard deviation(ADCstd),and mean ADC value ratio of lesion-to-liv-er parenchyma(ADCratio)were calculated.Regarding the joint diagnosis,a nomogram model was plotted using multivariate logistic regression analysis.The performance was assessed using the area under the receiver operating characteristic curve(AUC).Results:The ADCmean,ADCmin,ADCratio,and ADCstd were significantly associated with the identification of small HCC and benign nodules(p<0.001).For the joint diagnosis,the LI-RADS category(odds ratio[OR]=12.50),ADCmin(OR=0.14),and ADCratio(OR=0.12)were identified as independent factors for distinguishing HCCs from benign nodules.The joint nomogram model showed good calibration and discrimination,with a C-index of 0.947.Compared with the LI-RADS category alone,this nomogram model demon-strated a significant improvement in diagnostic performance,with AUC increasing from 0.820 to 0.967(p=0.001).Con-clusions:The addition of quantitative ADCs could improve the identification of small HCC and benign nodules catego-rized as LR-3 and 4 LR-4 in patients with cirrhosis.