Comparison and differentiation between intrahepatic cholangiocarcinoma and atypical liver abscess in MRI

Objective To access the value of MRI in differential diagnosis between intrahepatic cholangiocarcinoma and atypical hepatic abscess. Methods Retrospectively collecting and analyzing the clinical and MRI imaging data of 19 patients with intrahepatic cholangiocarcinoma (ICC) and 17 patients with atypical hepatic abscess, confirmed by reexamination after anti-inflammation therapy, surgery or puncture etiology, from June 2011 to July 2018 in Central Hospital of Lishui City.They were divided into ICC and abscess groups. All patients underwent routine liver plain MRI, DWI and contrast-enhanced MR scan. The MRI features of the two groups (including morphology, boundary, cystic change and necrosis, pseudocapsule, hemorrhage, lipid composition, the signature of lesion in different phases of MRI and surrounding tissue) were studied. Fisher exact test and t test were used. Result This study showed that there was statistical difference between the two groups in the following aspects, the presence of cystic degeneration, the degree of annular enhancement in arterial phase, the homogeneous enhancement in portal venous phase and balanced phase and the central filling enhancement sign (P<0.05).The results showed that necrotic cystic lesion was more common in the abscess group (15/17 cases) than in the ICC group (0/19 cases);in the cases with annular enhancement in arterial phase,the degree of enhancement in the ICC group (13/16 cases) was higher than that in the abscess group (2/9 cases); the enhancement of the central parenchyma of lesion on out-of-phase images (1/19 cases) was slower in the ICC group than that in the abscess group (14/17 cases);and the ICC group was likely to present as central filling enhancement compared to the abscess group. Conclusion The presence of cystic lesions in DWI, the enhancement degree of marginal parenchyma, the enhancement speed of central parenchyma and the whole enhancement pattern are essential signs for differentiating intrahepatic cholangiocarcinoma and atypical hepatic abscess. Key words: Liver neoplasms; Atypical liverabscess; Magnetic resonance imaging; Comparative study