Combining Techniques Boosts Diagnostic Sensitivity in Intrahepatic Cholangiocarcinoma

The combination of diffusion-weighted imaging (DWI) and hepatobiliary-phase (HBP) enhanced imaging can help physicians more accurately distinguish between cholangiocarcinoma and atypical liver abscesses, compared with using either technique alone, according to new study findings.

The study, which was based on a retrospective analysis of 68 patients, was published in Frontiers in Oncology.

The study aimed to solve a diagnostic conundrum related to intrahepatic mass-forming cholangiocarcinoma (IMCC), the most common subtype of intrahepatic cholangiocarcinoma. The authors explained that IMCC and liver abscesses often have similar characteristics, particularly if the abscesses are atypical.

“IMCC may present with fever as the first clinical symptom, similar to that of liver abscesses, whereas atypical liver abscesses may have no clinical manifestations or symptoms, similar to those of a liver tumor,” the authors wrote.

They added that “typical” liver abscesses tend to have a central area of necrotic liquefaction, a peripheral “ring-target sign,” and focal intrahepatic gas on CT images.

“Because both IMCCs and atypical liver abscesses may have the following characteristics of a single lesion, edge ring enhancement, and continuous enhancement on conventional CT imaging, it is very difficult to distinguish these 2 disease entities,” they continued.

Both MRI DWI and HBP Gadobenate dimeglumine (Gd-BOPTA) enhancement are tools that can be used to help distinguish between IMCC and atypical abscesses, but the authors said both have drawbacks when used in isolation.

For example, IMCC may have an overall high signal on DWI imaging, but if the tumor lesion is infected with bacteria, it might exhibit a heterogeneous signal suggestive of an atypical liver abscess.

“On the contrary, an atypical liver abscess with less or no necrosis, especially at the early stage of development, may present with a high signal or heterogeneous signal similar to that of a tumor,” they explained.

Since both DWI and HBP imaging alone can lead to misdiagnosis or delayed diagnosis, the investigators set out to see whether combining the 2 techniques would improve diagnosis.

They used a cohort of 43 patients with IMCC and 25 patients with atypical liver abscesses, and retrospectively examined their cases using DWI signals, absolute values of the contrast noise ratio at the HBP, and visibility.

Two-thirds of patients in the IMCC group had relatively high DWI signals and relatively high peripheral signals. In the abscess group, a majority had relatively high DWI signals, but only 1 had a relatively high peripheral signal. Instead, most of the patients with abscesses had relatively high central signals.

On T2 weighted imaging, IMCC was associated with a homogenous signal in most cases (53.5%), but patients with abscesses most often had heterogeneous signals or relatively high central signals (32% and 64%, respectively). HBP imaging showed significant differences in peripheral contrast noise ratios and visibility between the 2 cohorts, the authors said.

Overall, the authors found that HBP imaging outperformed DWI, but they said the sensitivity of DWI combined with enhanced HBP imaging led to significantly higher sensitivity than either of the two techniques alone.

The investigators said their results make a case not only for using both imaging methods, but also for expanding the use of Gd-BOPTA.

“The results of this study can provide a theoretical basis for differentiating IMCC from atypical liver abscess and improve the diagnostic rate,” they wrote. “At the same time, our study outcomes can also provide a basis for wide application of the liver specific contrast agent Gd-BOPTA.”

Reference

Xing L-H, Zhuo L-Y, Zhang Y, et al. DWI combined with hepatobiliary-phase enhanced imaging can better differentiate cholangiocarcinoma from atypical liver abscesses. Front Oncol. Published online May 13, 2022. doi:10.3389/fonc.2022.723089