Imaging bile duct tumors: staging

Cholangiocarcinoma imaging: from diagnosis to response assessment

Cholangiocarcinoma (CCA), a highly aggressive primary liver cancer arising from the bile duct epithelium, represents a substantial proportion of hepatobiliary malignancies, posing formidable challenges in diagnosis and treatment. Notably, the global incidence of intrahepatic CCA has seen a rise, necessitating a critical examination of diagnostic and management strategies, especially due to presence of close imaging mimics such as hepatocellular carcinoma (HCC) and combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA). Hence, it is imperative to understand the role of various imaging modalities such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), elucidating their strengths, and limitations in diagnostic precision and staging accuracy. Beyond conventional approaches, there is emerging significance of functional imaging tools including positron emission tomography (PET)-CT and diffusion-weighted (DW)-MRI, providing pivotal insights into diagnosis, therapeutic assessment, and prognostic evaluation. This comprehensive review explores the risk factors, classification, clinical features, and role of imaging in the holistic spectrum of diagnosis, staging, management, and restaging for CCA, hence serving as a valuable resource for radiologists evaluating CCA.

Cholangiocarcinoma Evaluation via Imaging and Artificial Intelligence

BACKGROUND

Cholangiocarcinoma (CCA) is a relatively rare malignant biliary system tumor, and yet it represents the second most common primary hepatic neoplasm, following hepatocellular carcinoma. Regardless of the type, location, or etiology, the survival prognosis of these tumors remains poor. The only method of cure for CCA is complete surgical resection, but part of patients with complete resection are still subject to local recurrence or distant metastasis.

SUMMARY

Over the last several decades, our understanding of the molecular biology of CCA has increased tremendously, diagnostic and evaluative techniques have evolved, and novel therapeutic approaches have been established. Key Messages: This review provides an overview of preoperative imaging evaluations of CCA. Furthermore, relevant information about artificial intelligence (AI) in medical imaging is discussed, as well as the development of AI in CCA treatment.

Peribiliary glands: development, dysfunction, related conditions and imaging findings

Peribiliary glands are minute structures that are distributed along the intrahepatic large bile ducts, extrahepatic bile duct, and cystic duct. These glands regulate many physiological functions, such as enzyme secretion. Pancreatic exocrine tissues and enzymes are often observed in peribiliary glands; thus, peribiliary glands are involved in enzyme secretion. As such, these glands can be affected by conditions such as IgG4-related sclerosing cholangitis based on commonalities with their pancreatic counterparts. Cystic changes in peribiliary glands can occur de novo, as part of a congenital syndrome, or secondary to insults such as alcoholic cirrhosis. Biliary tree stem/progenitor cells have recently been identified in peribiliary glands. These cells are involved in turnover and regeneration of biliary epithelia as well as in sclerosing reactions in some pathological conditions, such as primary sclerosing cholangitis and hepatolithiasis. Notably, hepatolithiasis is involved in mucin secretion by the peribiliary glands. Additionally, these cells are associated with the manifestation of several neoplasms, including intraductal papillary neoplasm, cystic micropapillary neoplasm, and cholangiocarcinoma. Normal peribiliary glands themselves are particularly small structures that cannot be recognized using any available imaging modalities; however, these glands are closely associated with several diseases, as mentioned above, which have typical imaging features. Therefore, knowledge of the basic pathophysiology of peribiliary glands is helpful for understanding biliary diseases associated with the peribiliary glands.

Improved oncologic outcome with chemoradiotherapy followed by surgery in unresectable intrahepatic cholangiocarcinoma

PURPOSE

To investigate the ability of chemoradiotherapy (CRT) to down-stage unresectable intrahepatic cholangiocarcinoma (IHCC) to resectable lesions, as well as the factors associated with achieving such down-staging.

METHODS

The study cohort comprised 120 patients diagnosed with stage I-IVA IHCC between 2001 and 2012. Of these patients, 56 underwent surgery and 64 received CRT as their initial treatment. The rate of curative resections for patients who received CRT was assessed, and the locoregional failure-free survival (LRFFS) and overall survival (OS) rates of these patients were compared to those of patients who underwent CRT alone.

RESULTS

Median follow-up was 36 months. A partial response after CRT was observed in 25% of patients, whereas a biologic response (a >70% decrease of CA19-9) was observed in 35%. Eight patients (12.5%) received curative resection after CRT and showed significantly improved LRFFS and OS compared to those treated with CRT alone (3-year LRFFS: 50 vs. 15.7%, respectively, p = 0.03; 3‑year OS: 50 vs. 11.2%, respectively, p = 0.012); these rates were comparable to those of patients who received initial surgery. Factors associated with curative surgery after CRT were gemcitabine administration, higher radiotherapy dose (biological effective dose ≥55 Gy with α/β = 10), and a >70% reduction of CA19-9.

CONCLUSION

Upfront CRT could produce favorable outcomes by converting unresectable lesions to resectable tumors in selected patients. Higher radiotherapy doses and gemcitabine-based chemotherapy yielded a significant reduction of CA19-9 after CRT; patients with these characteristics had a greater chance of curative resection and improved OS.

Multimodality imaging of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinomas account for approximately 20% of cases of cholangiocarcinomas. Three growth patterns or morphologic subtypes exist, including mass-forming, periductal-infiltrating, and intraductal-growth subtypes. Knowledge of these morphologic subtypes and their radiologic appearance aids in timely diagnosis, a key to optimizing patient outcomes. The morphologic variability of intrahepatic cholangiocarcinomas has a direct impact on the diagnostic sensitivity and specificity of various diagnostic imaging modalities, including ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP), and positron emission tomography (PET). The following review emphasizes optimal imaging technique for each of these modalities and reviews the imaging appearance of each morphologic subtype of intrahepatic cholangiocarcinoma.

Imaging of Cholangiocarcinoma

Cholangiocarcinoma (CC) is the second most common primary hepatobiliary tumour, and it is increasing in incidence. Imaging characteristics, behaviour, and therapeutic strategies in CC differ significantly, depending on the morphology and location of the tumour. In cross-sectional imaging, CCs can be classified according to the growth pattern (mass-forming, periductal infiltrating, intraductal) and the location (intrahepatic, perihilar, extrahepatic/distal). The prognosis of CC is unfavourable and surgical resection is the only curative treatment option; thus, early diagnosis (also in recurrent disease) and accurate staging including the evaluation of lymph node involvement and vascular infiltration is crucial. However, the diagnostic evaluation of CC is challenging due to the heterogeneous nature of the tumour. Diagnostic modalities used in the imaging of CC include transabdominal ultrasound, endosonography, computed tomography, magnetic resonance imaging with cholangiopancreatography, and hybrid imaging such as positron emission tomography/computed tomography. In this review, the potential of cross-sectional imaging modalities in primary staging, treatment monitoring, and detection of recurrent disease will be discussed.

SALL4 is a novel therapeutic target in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the most common and deadly disease of the biliary tree due to its poor prognosis. Sal-like protein 4 (SALL4), a stem cell marker, has been identified as a potential target for aggressive hepatocellular carcinoma (HCC). In our study, 175 ICC cases with an average age of 55 years were included, and 53% (93/175) were male. And 28 adjacent non-tumor tissues were also collected. The SALL4-positive immunoreactivity was detected in a total of 102 ICC cases (58%), whereas all 28 adjacent tissues showed negative staining. Univariate analysis, showed that the SALL4-positive ICC cases had significantly more frequent lymph nodal metastasis (P = 0.0460), vascular invasion (P < 0.0001), and nerve invasion (P < 0.0001). Furthermore, the strong SALL4-positive cases (n = 7, 5 months) had shorter overall survival, when compared to moderate SALL4-positive (n = 46, 9 months) or SALL4-negative cases (n = 73, 7 months), respectively. Our data also suggest that SALL4 may be involved in the regulation of epithelial-mesenchymal transition (EMT) in ICC. Those results for the first time indicate an oncogenic role of SALL4 in ICC. Therefore, SALL4 may serve as a promising therapeutic target for ICC.

Biphenotypic hepatic tumors: imaging findings and review of literature

PURPOSE

To describe imaging findings in biphenotypic hepatic tumors (BPT) and a proposal for new imaging classification based on contrast-enhanced imaging.

METHODS

Retrospective review of CT, MRI, PET/CT, and ultrasound findings in 39 patients with histologically confirmed BPT was performed. Tumor markers including AFP, L3 fraction, CA 19.9, CA 125, and CEA were recorded. Based on the dynamic enhancement features, BPT were categorized into 4 enhancement patterns (Types 1-4). Enhancement patterns were correlated with other imaging findings and tumor markers. Imaging features and tumor markers that were not consistent with diagnosis of hepatocellular carcinoma or intrahepatic cholangiocarcinoma based on enhancement pattern were considered discordant findings.

RESULTS

Enhancement patterns in 29 patients (CT/MR) included 23 Type 2 (continuous peripheral rim of late arterial hyperenhancement with washout or fade in portal venous and/or delayed phases, ±delayed central enhancement) and 2 of each Types 1, 2, and 3. Discordant imaging findings were present in two patients with Type 2 pattern and in one patient with Type 1 pattern. Both AFP and CA 19.9 were elevated in 15 of 33 of patients. Tumor markers AFP and CA 19.9 were discordant in 17 of 21 patients with Type 2 pattern, two of two patients with Type 3 pattern. Most BPTs were markedly PET avid with average SUV max of 8.2. Most frequent ultrasound appearance is peripheral hypoechogenicity and central hyperechogenicity.

CONCLUSIONS

BPT most commonly present with imaging features similar to cholangiocarcinoma or metastases. BPT can be suggested when imaging findings or tumor markers are discordant with the most likely diagnosis based on enhancement pattern.

Imaging spectrum of cholangiocarcinoma: role in diagnosis, staging, and posttreatment evaluation

Cholangiocarcinoma, a tumor of biliary epithelium, is increasing in incidence. The imaging appearance, behavior, and treatment of cholangiocarcinoma differ according to its location and morphology. Cholangiocarcinoma is usually classified as intrahepatic, perihilar, or distal. The three morphologies are mass-forming, periductal sclerosing, and intraductal growing. As surgical resection is the only cure, prompt diagnosis and accurate staging is crucial. In staging, vascular involvement, longitudinal spread, and lymphadenopathy are important to assess. The role of liver transplantation for unresectable peripheral cholangiocarcinoma will be discussed. Locoregional therapy can extend survival for those with unresectable intrahepatic tumors. The main risk factors predisposing to cholangiocarcinoma are parasitic infections, primary sclerosing cholangitis, choledochal cysts, and viral hepatitis. Several inflammatory conditions can mimic cholangiocarcinoma, including IgG4 disease, sclerosing cholangitis, Mirizzi's syndrome, and recurrent pyogenic cholangitis. The role of PET in diagnosis and staging will also be discussed. Radiologists play a crucial role in diagnosis, staging, and treatment of this disease.

Primary Poorly Differentiated Squamous Cell Carcinoma of the Extrahepatic Bile Duct

Squamous cell carcinoma of the extrahepatic bile duct is quite rare. A 77-year-old woman with jaundice and general fatigue was referred to our hospital. Multiphase contrast-enhanced computed tomography visualized a 17-mm solid mass in the junction of the cystic and common bile ducts. The patient underwent pylorus-preserving pancreaticoduodenectomy. The pathological findings demonstrated keratin-positive poorly differentiated squamous cell carcinoma of the extrahepatic bile duct (T3N0M0, stage IIIA). Although adjuvant chemotherapy with gemcitabine was administered, the patient exhibited local recurrence at the site of anastomosis of biliojejunostomy 20 months after resection and died 32 months after resection.

Noninvasive Imaging of the Biliary Tree for the Interventional Radiologist

Patients with suspected biliary tract disease often pose a diagnostic challenge to the clinician and radiologist. Although advances across all imaging modalities, including ultrasound, computed tomography, and magnetic resonance, have improved our diagnostic accuracy for biliary disease, many of the imaging findings remain nonspecific. Recognition of key imaging findings combined with knowledge and understanding of the clinical context is essential to piecing together a diagnosis and guiding management for patients with biliary disease. Although there is a wide range of biliary pathology, interventional radiologists most commonly play a role in the management of biliary obstruction and leak.

Radiological diagnosis in cholangiocarcinoma: Application of computed tomography, magnetic resonance imaging, and positron emission tomography

The purpose of radiological imaging in patients with suspected or known cholangiocarcinoma (CCA) is tumour detection, lesion characterization and assessment of resectability. Different imaging modalities are implemented complementary in the diagnostic work-up. Non-invasive imaging should be performed prior to invasive biliary procedures in order to avoid false positive results. For assessment of intraparenchymal tumour extension and evaluation of biliary and vascular invasion, MRI including MRCP and CT are the primarily used imaging modalities. The role of PET remains controversial with few studies showing benefit with the detection of unexpected metastatic spread, the differentiation between benign and malignant biliary strictures, and for discriminating post therapeutic changes and recurrent CCA.

Diagnostic performance of CT and MRI in distinguishing intraductal papillary neoplasm of the bile duct from cholangiocarcinoma with intraductal papillary growth

OBJECTIVES

We aimed to evaluate the diagnostic performance of CT and MRI for distinguishing intraductal papillary neoplasm of the bile duct (IPNB) from cholangiocarcinoma (CC) with intraductal papillary growth (IPG).

METHODS

Forty-two patients with either IPNB or CC with IPG proven by histopathology were independently reviewed in retrospect. Strict criteria for diagnosis of IPNB included presence of the designated imaging features as follows: local dilatation of the bile duct, nodule within the dilated bile duct, growing along the interior wall of bile duct. Any lesion that was not consistent with the criteria was classified as CC with IPG. Sensitivity, specificity, positive and negative predictive values for characterization of IPNB were calculated, and k test was used to assess the level of agreement.

RESULTS

Two imaging reviewers correctly identified 21 of 26 (80.8%) and 22 of 26 (84.6%) IPNB cases, respectively. Alternatively, they correctly identified 14 of 16 (87.5%) and 15 of 16 (93.8%) CC with IPG, respectively. Agreement between the two reviewers was perfect (k = 0.81) for the diagnosis of IPNB and differentiation from CC with IPG.

CONCLUSIONS

By using our designated diagnostic criteria of CT and MRI, IPNB can be accurately identified and possible to be distinguished from CC with IPG.

KEY POINTS

• IPNB can accurately be identified by using defined diagnostic criteria at CT/MRI. • IPNB has some characteristic CT and MR imaging features. • IPNB is a rare entity; up until now it might have been misdiagnosed.

Bile duct tumors

Bile duct tumors are benign or malignant lesions which may be associated to risk factors or potentially malignant lesions. They constitute an heterogenous entities group with a different biological behavior and prognosis according to location and growth pattern. We revise the role of the radiologist in order to detect, characterize and stage these tumors, specially the importance of their classification when deciding an appropriate management and treatment.

Diagnosis and management of intrahepatic cholangiocarcinoma: a comprehensive update for the radiologist

There is increasing focus on intrahepatic cholangiocarcinoma (IHCC) due to its rising incidence worldwide and relatively poor prognosis, with the revised TNM classification (2009) introducing a separate staging system for IHCC for the first time. In this article, we comprehensively review the current role of the radiologist in the diagnosis and management of patients with IHCC.