Apparent diffusion coefficient value of mass-forming intrahepatic cholangiocarcinoma: a potential imaging biomarker for prediction of lymph node metastasis.

PURPOSE

To compare the differences of MR features between mass-forming intrahepatic cholangiocarcinoma (IMCC) with and without lymph node metastasis (LNM) and to search for new imaging biomarkers for predicting LNM.

MATERIALS AND METHODS

The study included 91 patients with histopathologically confirmed single IMCC (20 patients with LNM and 71 patients without LNM). Findings of preoperative MR imaging including diffusion-weighted imaging (DWI) (b value 0, 500 mm/s) were analyzed and apparent diffusion coefficient (ADC) values (b = 500 mm/s) were calculated. Logistic regression analysis was performed to identify independent predictors of LNM. The diagnostic performance of independent predictors was assessed by receiver operating characteristic (ROC) and area under the curve (AUC) was compared.

RESULTS

Larger tumor size (p = 0.001), diameter of largest lymph node (LN) > 1 cm (p < 0.001), higher ADC value of primary IMCC lesion (ADC value) (p = 0.001), and positive CA19-9 level (p = 0.018) were correlated with LNM. Multivariate logistic regression analysis demonstrated that ADC value (odds ratio, 3.347; p = 0.001) and diameter of largest LN > 1 cm (odds ratio, 7.571; p = 0.004) were independent predictors of LNM. The AUCs for ADC value, diameter of largest LN > 1 cm,and combined method (the combination of ADC value and diameter of largest LN > 1 cm) were 0.782, 0.701,and 0.857, respectively. The AUC for combined method was significantly higher than that of diameter of largest LN > 1 cm (p = 0.033).

CONCLUSION

ADC value can be a potential imaging biomarker for predicting LNM of IMCC, especially in combination with diameter of largest LN > 1 cm.