Mass-forming intrahepatic cholangiocarcinoma: Can diffusion-weighted imaging predict microvascular invasion?

BACKGROUND: Microvascular invasion (MVI) is a risk factor influencing the survival rate of patients with mass-forming intrahepatic cholangiocarcinoma (IMCC).

PURPOSE: To investigate whether diffusion-weighted imaging (DWI) could be useful in predicting MVI of IMCC.

STUDY TYPE: Retrospective.

SUBJECTS: Eighty patients with surgically resected single IMCC (21 MVI-positive lesions and 59 MVI-negative lesions).

FIELD STRENGTH/SEQUENCE: Preoperative hepatic MRI (1.5T), including T1 - and T2 -weighted images (T1 WI, T2 WI), DWI, and dynamic enhancement imaging.

ASSESSMENT: Morphologic characteristics including contour of the lesion, biliary dilation and hepatic capsule retraction, signal features on T1 WI, T2 WI, and DWI, and dynamic enhancement patterns were qualitatively evaluated. The quantitative analysis was performed for the size and apparent diffusion coefficient (ADC) values.

STATISTICAL TESTS: Chi-square test, Fisher's exact test, and the independent t-test were used for univariate analysis to determine the relationships between these radiological parameters and the presence of MVI. Logistic regression analysis was used to identify the independent predictors of MVI among these radiological parameters. Receiver operating characteristic curve analysis was performed to evaluate their diagnostic performance.

RESULTS: Larger tumor size (P = 0.006) and higher ADC values (P < 0.001) were positively correlated with MVI. Multivariate logistic regression analysis demonstrated that the ADC value (odds ratio, 3.099; P = 0.001) was an independent predictor for MVI of IMCC. The ADC value for MVI of IMCC showed an area under the receiver operating characteristic curve of 0.782 (optimal cutoff value was 1.59 × 10-3 mm2 /s).

DATA CONCLUSION: Larger tumor size was associated with MVI and higher ADC values can be a useful predictor of MVI during the preoperative evaluation of IMCC.

LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.