Objective To explore the predictive value of apparent diffusion coefficient (ADC) in predicting microvascular invasion (MVI) in combined hepatocellular-cholangiocarcinoma (cHCC-CCA).

Methods From January 2016 to June 2019, 67 patients with mixed liver cancer (≤ 5 cm) confirmed by preoperative MRI and postoperative pathology from Zhongshan Hospital, Fudan University were included and divided into MVI positive group (n=26) and MVI negative group (n=41) according to the presence or absence of MVI. Univariate and multivariate analyses were used to analyze the risk factors of MVI, and the receiver operating characteristic curve was used to evaluate their diagnostic efficacy.

Results The univariate retrospective analysis showed that the ADC value of the microvascular invasion positive group and the negative group was (1.268±0.571)×10^-3 mm²/s and (1.432±0.315)×10^-3 mm²/s, with statistically significant difference between the two groups (P=0.009). There was also a statistically significant difference in the peritumoral enhancement between the microvessel-positive group and the negative group (P=0.001). Logistic regression results showed that, ADC value is an independent predictor of microvascular invasion in cHCC-CCA (HR=5.421, P=0.025). The ADC value predicted the AUC of cHCC-CCA microvascular invasion was 0.685 (95%CI 0.539-0.756). When the ADC cut-off value is 1.378×10^-3 mm²/s, the Youden index is 0.4.

Conclusions ADC value is an independent factor predicting microvascular invasion of combined hepatocellular-cholangiocarcinoma (≤ 5 cm), and has a certain predictive value for MVI.