Intrahepatic cholangiocarcinoma: relationship between tumor imaging enhancement by measuring attenuation and clinicopathologic characteristics

Abstract

Purpose: Arterial enhancement of intrahepatic cholangiocarcinoma (ICC) has been noted. To precisely identify the characteristics of tumor enhancement patterns, we examined the relationship between CT attenuation in the tumor and clinicopathological parameters or prognosis.Methods: Subjects were 42 ICC patients who had undergone hepatectomy. Microvessel density (MVD) determined by CD34 staining was compared with imaging. Attenuation was calculated in images from multi-detector CT of tumor and non-tumorous regions. Enhancement patterns were divided into two groups: arterial enhancement with higher attenuation (>16 HU; Hyper group, n=12); and arterial enhancement with lower attenuation (Hypo group, n=30).Results: Univariate analysis identified high tumor marker level, increased size, less-differentiation, incomplete resection, increased bleeding and lower MVD as significantly associated with poor survival (p<0.05). Increased attenuation throughout the whole ICC correlated significantly with radiological findings and MVD. Concomitant hepatitis, well-differentiation, and smaller tumor were more significantly frequent in the Hyper group than in the Hypo group (p<0.05). Postoperative early recurrence was significantly less frequent in the Hyper group, and overall survival was significantly better in the Hyper group (p<0.05). Conclusions:Increased CT attenuation correlated with ICC tumor vascularity. Increased tumor enhancement in the arterial phase was associated with chronic hepatitis, lower malignancy and better survival.Key words: intrahepatic cholangiocarcinoma-tumor enhancement-multidetector computed tomography-prognosis-hepatectomy Nanashima et al., Page 3 Intrahepatic cholangiocarcinoma (ICC) is a well-characterized liver cancer for which various prognostic risk factors have been clarified [1][2][3]. ICC is composed of cells that mostly resemble those of the peripheral bile ducts, but recent reports have suggested that ICC may not always display uniform characteristics [4][5][6][7][8]. ICC can be classified into subgroups according to macroscopic findings, with clinical and pathological characteristics and prognosis differing significantly among subgroups [9,10].While diagnosis of the ICC subtype would be useful for predicting prognosis and determining the need for adjuvant treatments with hepatic resection, clearly distinguishing subgroups is often difficult, particularly in advanced tumors. Although a variety of prognostic parameters have been identified in recent research, the definitive factors associated with poor prognosis have not been well clarified [11,12]. Recent histological and molecular studies have revealed that tumor vascularity of ICC is closely associated with malignant behavior and patient prognosis [13,14]. Higher tumor vascularity might be related to the presence of chronic viral hepatitis, which is also related to carcinogenesis for hepatocellular carcinoma (HCC) [15]. We have previously examined histological parameters in ICC and clarified that higher tumor vascularity as dete...

Intrahepatic mass-forming cholangiocarcinoma: prognostic value of preoperative gadoxetic acid-enhanced MRI

“…Although IMCC is typically hypovascular, IMCC arising from chronic viral hepatitis and the cirrhotic or pre-cirrhotic liver is more likely to be hypervascular after the malignant transformation of the cholangiocytes [27]. It has been reported that hypervascular versus hypovascular IMCC on arterial phase CT correlates with reduced malignant behaviour and better survival [13][14][15]28]. In a previous study, welldifferentiated tumours were found to have greater enhancement on gadoxetic acid-enhanced MRI than moderately or poorly differentiated IMCCs [16].…”

“…There have been a few reports indicating that the imaging findings of IMCC correlate with prognosis [12][13][14][15]. IMCCs with abundant tumour fibrous stroma, defined as "scirrhous type", exhibit a delayed enhancement area on CT, which correlates with poor prognosis [12].…”

Imaging of Cholangiocarcinoma

“…Two studies including 42 and 70 patients with iCC and operative resection showed strong correlations between augmented arterial tumour enhancement in preoperative CT, histopathological vascularity, and higher survival rate. Histological examination of these tumours demonstrated a smaller amount of fibrotic tissue and necrosis but a higher cellularity [30,31]. The estimated overall accuracy of CT in evaluating tumour resectability ranges between 60 and 75% [32,33].…”

Intrahepatic cholangiocarcinomas mimicking other lesions

“…This hypervascular appearance has been suggested to correlate with highly cellular tumors containing less fibrous components or a more vascular component intermixed with the fibrous tissue, smaller size, and a better prognosis [26,[28][29][30], and is also more prevalent in cholangiocarcinoma that develops in cirrhotic liver [15]. This hypervascular appearance was seen in all of the lesions in our cohort.…”