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Page 4 of 14 Afyouni et al. Hepatoma Res 2023;9:28 https://dx.doi.org/10.20517/2394-5079.2023.29

after the administration of a contrast agent, highlighting the arterial, portal venous, and delayed phases of
tumor enhancement. Similarly, dynamic contrast-enhanced MRI (DCE-MRI) involves the acquisition of
images before and after the administration of a gadolinium-based contrast agent, providing information
[15]
about the tumor’s vascular pattern and perfusion .

Gd-DTPA or its derivatives, such as Gd-DTPA-EOB (Eovist®), can be used for post-contrast MRI. Eovist,
hepatocyte-specific contrast agents (HSCAs), are taken up by hepatocyte transporters and are discharged via
the biliary tree. In the hepatobiliary phase, a lesion will maintain contrast only if it contains hepatocytes,
which helps refine differential diagnosis. Eovist has been demonstrated to be more effective at identifying
and characterizing hepatic lesions in patients with diffuse liver disease in which ICCs may show atypical
enhancement patterns after gadolinium-based extracellular contrast agents. Hepatocyte-specific
extracellular contrast agents like Eovist increase the liver's post-contrast signal intensity, making ICC more
apparent and hypointense on both early and delayed phase sequences [Figure 3]. This approach contrasts
[16]
the lesion from the liver tissue, making tumor size and satellite lesions, which occur in 10%-20% of ICCs,
easier to assess .
[16]
In mass-forming cholangiocarcinoma, Eovist causes the “gadoxetic acid cloud” indication on hepatobiliary
imaging. The fibrotic stroma may have extracellular contrast accumulation. Hepatobiliary phase imaging
can help identify intrahepatic metastases, daughter nodules, and other abnormalities associated with poor
mortality . Moderately differentiated tumors often exhibit more relative enhancement in the hepatobiliary
[17]
phase than poorly differentiated cancers. The hepatobiliary phase can also demonstrate a higher relative
tumor enhancement .
[18]
THE ROLE OF DIAGNOSTIC RADIOLOGY IN THE STAGING AND PROGNOSIS
Resectable ICC
Numerous staging methods estimate the prognosis of patients with resectable ICC [19-22] . The most used
technique is the American Joint Committee on Cancer staging system (AJCC) staging system, a tumor,
[23]
nodes, and metastases (TNM) staging system . Due to the restricted number of tumor-related
characteristics and the inability to customize prognostication for unresectable tumors, this staging approach
has drawn criticism . Numerous nomograms have also been created to improve outcome prediction, some
[21]
of which have shown superior accuracy to the AJCC staging system [19,22,24,25] . These prognostic models
consider various factors, such as certain biomarkers, anatomical-related imaging features, and specific
pathological parameters. However, none of them contain functional information about a patient's tumor.
Furthermore, similar to the AJCC staging system, they are all based on tissue acquisition and may not be
applied in unresectable ICC patients.

The role of radiomics or radiogenomics in ICC prognosis has been assessed in a number of research
studies [26-38] , and the evaluation of recurrence following surgical resection has been the main focus [36,39-42] .
Yang et al. evaluated MRI-extracted quantitative features for evaluation of overall survival in ICC patients
and developed a combined model integrating radiomics features with clinical factors that increased the
precision of prediction compared with TNM stage alone .
[43]
Unresectable ICC
Due to frequent delays in diagnosis, about 70% of patients with ICCs present with advanced-stage tumors
and are considered unresectable . In addition, many patients have comorbid conditions that prevent them
[44]
from being candidates for resection; these patients may be eligible for loco-regional therapy. In this regard,
there are challenges for tumor staging and monitoring treatment response.