MR signal intensity changes in hepatic parenchyma with ductal dilation caused by intrahepatic cholangiocarcinoma

A case of focal confluent hepatic fibrosis in the patient with hepatitis C virus-related liver cirrhosis: a mimic of cholangiolocellular carcinoma

During routine ultrasound examination, a hyperechoic mass was detected in the anterior segment of the liver in an 80-year-old woman with hepatitis C virus-related cirrhosis. Computed tomography and magnetic resonance imaging findings suggested a malignant tumor with abundant fibrous stroma, similar to cholangiolocellular carcinoma. However, subsequent partial hepatectomy revealed a mass characterized by abundant fibrosis without tumor cells, dilated blood vessels, and marginal ductular reaction. Accordingly, focal confluent fibrosis was diagnosed. Generally, the diagnosis of focal confluent fibrosis is straightforward because of its well-established imaging characteristics. However, its differentiation from a malignant tumor can occasionally be difficult because of variation in presentation depending on the amount of fibrous stroma and the degree of inflammatory cell infiltration. In the present case, diagnosis was difficult because the lesion was more localized than usual, presenting a mass-like shape, and there was obvious hyperintensity on T2-weighted imaging and ring-shaped hyperintensity on diffusion-weighted imaging. Moreover, hepatic capsular retraction was indistinct, which can be one of the key findings of focal confluent fibrosis. When a hepatic mass is associated with a fibrous lesion, focal confluent fibrosis should be considered in the differential diagnosis, even though the lesion is associated with several atypical findings.

Delayed-phase dynamic CT enhancement as a prognostic factor for mass-forming intrahepatic cholangiocarcinoma

PURPOSE

To retrospectively determine whether the degree of contrast material enhancement at delayed-phase dynamic computed tomography (CT) for intrahepatic cholangiocarcinoma (ICC) is related to the patient's prognosis after surgery.

MATERIALS AND METHODS

Neither institutional review board approval nor informed consent was required for this retrospective evaluation. Thirty-two patients (22 men, 10 women; mean age, 60.8 years; range, 33-80 years) with mass-forming ICC underwent dynamic CT. Delayed CT images obtained 4-6 minutes after the injection of contrast material were evaluated by two radiologists. Patients were classified in consensus into one of two groups: Group 1 included those in whom more than two-thirds of the tumor showed enhancement on delayed-phase scans. Group 2 included those in whom less than two-thirds of the tumor showed enhancement on delayed-phase scans. The imaging findings were correlated with pathologic findings. Survival curves were drawn by using the Kaplan-Meier method, and the differences between the groups were compared with the log-rank test. Multivariate analysis was performed to clarify prognostic factors.

RESULTS

There were 13 patients in group 1 and 19 in group 2. The degree of enhancement on the delayed-phase images showed statistically significant correlation with the amount of fibrous stroma (P < .001) and the frequency of perineural invasion (P < .01). The survival rate in group 1 was significantly lower than that in group 2 (P = .016). Multivariate analysis revealed that enhancement of more than two-thirds of the ICC was a significant and independent prognostic factor.

CONCLUSION

The degree of enhancement on delayed-phase CT scans is a useful indicator for prediction of the prognosis of patients with mass-forming ICC.

Segmental high intensity on T1-weighted hepatic MR images

BACKGROUND

We investigated the diagnostic importance of segmental high-intensity (SHI) areas not corresponding to mass lesions on T1-weighted magnetic resonance (MR) images.

METHODS

We conducted a retrospective investigation of hepatic MR images obtained from 634 patients during a 4-year period at our institution. Images were compared with findings reported in the patients' medical records. There were 16 patients (2.5%) with SHI areas not corresponding to a mass lesion. We compared MR images with plain computed tomographic (CT) scans (n = 16), angiograms (n = 12), and histologic findings (n = 10).

RESULTS

The segments with intrahepatic bile duct dilatation showed hyperintensity on T1-weighted images. In six of 16 patients, the biliary duct was more dilated in the area of hyperintensity than in areas without hyperintensity. The SHI areas appeared as areas of low attenuation (n = 13), high attenuation (n = 1), or isoattenuation (n = 2) on plain CT scans. Histologically, these areas showed ductular proliferation and deposition of bile pigment within the hepatocytes.

CONCLUSION

Segmental areas of increased signal intensity on T1-weighted images were probably due to intrahepatic cholestasis.

Magnetic Resonance Imaging of cholangiocarcinoma

Preoperative imaging with MRI/MRA/MRCP is an accurate non-invasive method for staging cholangiocarcinoma, and determining resectability. It provides information regarding tumor size, extent of bile duct involvement, vascular patency, extrahepatic extension, nodal or distant metastases, and the presence of lobar atrophy. MRCP is better for demonstrating bile ducts distal to the stricture, although with ERCP, therapeutic intervention such as stent placement and biopsy can be performed.

Computed tomography and magnetic resonance imaging evaluation of liver cancer

Focal liver lesions occur commonly and with varying histology, each requiring radically different management. There are a multitude of imaging modalities currently being used for detecting and characterizing focal liver neoplasms. The primary modalities include ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and rarely, angiography. CT and MRI have benefited from rapid technologic advances, and MRI, in particular, from the advent of new contrast agents.

MRI of clonorchiasis and cholangiocarcinoma

Intrahepatic cholangiocarcinomas are usually categorized as peripheral cholangiocarcinoma or hilar cholangiocarcinoma on the basis of the site of origin. Clonorchiasis is a trematodiasis caused by chronic infestation of liver flukes, which are largely confined to the Orient, from Japan to Vietnam. The close relationship between clonorchiasis and cholangiocarcinoma has long been emphasized. This paper discusses the efficacy and possible roles of MRI for imaging clonorchiasis and cholangiocarcinoma of the liver. Although sonography, CT, and direct cholangiography have been used traditionally to diagnose these diseases, the role of MRI has been increasing rapidly with dramatic progress of the MRI techniques. We review MRI findings of clonorchiasis and cholangiocarcinoma and discuss the potential usefulness of MRI.