Gadoxetate disodium-enhanced MRI of mass-forming intrahepatic cholangiocarcinomas: imaging-histologic correlation.
OBJECTIVE
The purpose of this study was to describe the enhancement patterns of mass-forming intrahepatic cholangiocarcinomas on gadoxetate disodium-enhanced MR images using imaging-histologic correlation.


METHODS
We retrospectively evaluated the preoperative gadoxetate disodium-enhanced MR images of 19 patients with mass-forming intrahepatic cholangiocarcinomas. Two readers independently interpreted enhancement patterns on arterial (globally high, rimlike), dynamic (washout, progressive), and hepatobiliary (target, nontarget) phase images. Dynamic enhancement was categorized as washout (hypoenhancement on later phase compared with arterial phase images) or progressive (persistent or gradually increased enhancement). Tumor enhancement ratio and tumor-to-liver signal difference curves were analyzed. The enhancement patterns were correlated with the extent of stromal fibrosis within the tumors.


RESULTS
Rimlike arterial enhancement (89%, reader 1; 84%, reader 2) and a progressive dynamic pattern (89%, both readers) were predominant. Tumor enhancement ratio increased gradually from the arterial to the equilibrium phase then decreased in the hepatobiliary phase, but the tumor signal intensities were lower than liver signal intensity in all phases. The two lesions that both readers considered to have globally high arterial enhancement and a washout dynamic pattern presented with minimal or scattered stromal fibrosis. Target appearance in the hepatobiliary phase (reader 1, 42%; reader 2, 47%) was more commonly seen in tumors with central stromal fibrosis (reader 1, p = 0.025; reader 2, p = 0.001).


CONCLUSIONS
Mass-forming intrahepatic cholangiocarcinomas may be characterized by rimlike enhancement and a progressive dynamic pattern on gadoxetate disodium-enhanced MR images, and these features seem related to the extent of stromal fibrosis in the tumor. Furthermore, mass-forming intrahepatic cholangiocarcinomas may have a pseudowashout pattern on gadoxetate disodium-enhanced MR images because of progressive background liver enhancement. Therefore, radiologists need to be aware of this pattern as a possible pitfall.
1 Department of Radiology, Research Institute of Radiological Science, Yonsei University Severance Hospital, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea.
Hyeon Tae
HT
Jeong
Myeong-Jin
MJ
Kim
Yong Eun
YE
Chung
Jin Young
JY
Choi
Young Nyun
YN
Park
Ki Whang
KW
Kim
D001650:Bile Duct Neoplasms / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic / Q000473:pathology*; D018281:Cholangiocarcinoma / Q000473:pathology*; D002760:Cholangiopancreatography, Endoscopic Retrograde; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA