Intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases: is the differential diagnosis using diffusion-weighted MRI possible?

Abstract

Background Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion ( b = 800 s/mm). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions.

Imaging Spectrum of Intrahepatic Mass-Forming Cholangiocarcinoma and Its Mimickers: How to Differentiate Them Using MRI

“…Target sign, consisting of diffusion restriction at the periphery of the lesion and low signal intensity in its central parts on high- b -value diffusion weighted imaging (DWI), could be considered to be a pathognomonic finding in mICC [ 16 , 17 ]. It can be attributed to the loose central fibrotic stroma with accompanying edema that is responsible for low signal intensity in DWI, while the periphery of the lesion is composed of densely packed viable tumor cells that cause diffusion restriction and dark rings on the apparent diffusion coefficient (ADC) map ( Figure 3 ) [ 16 ].…”

“…Although the central T2-weighted hypointensity and bile duct dilatation proximal of the tumor are considered to be typical for mICC, they can also occur in liver metastases [ 68 ]. In such cases, other imaging features, including shape of the lesion, capsular retraction, and portal lymphadenopathy, are suggestive of mICCs [ 17 ]. Recent studies have stressed the importance of imaging appearance in DWI for the differential diagnosis.…”

Diagnostic performance of apparent diffusion coefficient values for the differentiation of intrahepatic cholangiocarcinoma from gastrointestinal adenocarcinoma liver metastases

“…In a recent study, Kovac et al investigated the contribution of ADC values in the differentiation between solitary hypovascular liver metastases and IHCC. 16 They reported lower ADC values in the peripheral enhancing areas and higher in the central parts in IHCC compared to solitary hypovascular metastases. Authors explained that high ADC values in the central part of IHCC are related to rich fibrous tissue.…”

Cholangiocarcinoma Evaluation via Imaging and Artificial Intelligence

“…It may also contribute to the differentiation between ICC (Fig. 3) and other hepatic malignancies, such as solitary hypovascular liver metastases [71] and HCC (Fig. 4) [72].…”