Gadoxetate disodium-enhanced MRI of mass-forming intrahepatic cholangiocarcinomas: imaging-histologic correlation
Hyeon Tae Jeong1, Myeong-Jin Kim, Yong Eun Chung
11 Department of Radiology, Research Institute of Radiological Science, Yonsei University Severance Hospital, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea.
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.
Materials And 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).
Conclusion:
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.
Insights
Mass-forming intrahepatic cholangiocarcinomas show rimlike arterial enhancement and progressive dynamic patterns on MRI. These features correlate with stromal fibrosis, and radiologists should note potential pseudowashout patterns.
Area of Science:
- Radiology
- Oncology
- Hepatobiliary Imaging
Background:
- Intrahepatic cholangiocarcinoma (ICC) is a primary liver malignancy.
- Accurate imaging characterization of mass-forming ICC is crucial for diagnosis and management.
- Gadoxetate disodium-enhanced MRI offers unique dynamic and hepatobiliary phase information.
Purpose of the Study:
- To describe the enhancement patterns of mass-forming ICC on gadoxetate disodium-enhanced MRI.
- To correlate these imaging findings with histologic features, specifically stromal fibrosis.
- To identify potential imaging pitfalls for radiologists.
Main Methods:
- Retrospective review of preoperative MRI in 19 patients with mass-forming ICC.
- Independent assessment of enhancement patterns (arterial, dynamic, hepatobiliary phases) by two readers.
- Correlation of enhancement patterns with the extent and distribution of stromal fibrosis.
Main Results:
- Predominant findings included rimlike arterial enhancement (84-89%) and progressive dynamic enhancement (89%).
- Tumor enhancement ratio increased then decreased in the hepatobiliary phase, with lower signal intensity than liver.
- Hepatobiliary phase target appearance was associated with central stromal fibrosis (p=0.001-0.025).
Conclusions:
- Mass-forming ICC commonly exhibit rimlike arterial and progressive dynamic enhancement patterns on gadoxetate disodium-enhanced MRI.
- These patterns are related to the degree of stromal fibrosis within the tumor.
- Radiologists should be aware of a potential pseudowashout pattern due to background liver enhancement.
