Evaluation of hepatic tumor portal perfusion using mesenteric angiography: A pilot study in 5 dogs.

BACKGROUND: Mesenteric angiography is a sensitive method for visualizing portal perfusion in the dog. OBJECTIVES: To evaluate hepatic portal perfusion in dogs with incompletely resectable hepatic tumors using mesenteric angiography. ANIMALS: Five client-owned dogs with incompletely resectable hepatic tumors evaluated with mesenteric angiography. METHODS: Retrospective case series. Electronic medical records at the Animal Medical Center were analyzed to identify dogs that underwent mesenteric portography to determine blood flow to nonresectable hepatic tumors and subsequently determine ideal routes for transarterial embolization, vascular stent placement, or both. The images obtained from mesenteric angiography were analyzed and compared to those obtained from computed tomography angiography. RESULTS: Portography was accomplished using direct mesenteric venography in 3 dogs with hepatocellular carcinoma (HCC), cranial mesenteric arteriography in 1 dog with hepatic adenoma or well-differentiated HCC, and via splenic arteriovenous fistula in 1 dog with diffuse hepatic hemangiosarcoma metastases. Mean pixel densities in areas of hepatic tumor growth identified statistically significant decreases in portal blood flow (P = .02) compared to normal hepatic parenchyma. CONCLUSIONS AND CLINICAL IMPORTANCE: Initial findings indicate that the blood supply to large and metastatic hepatic tumors in dogs may correlate with that in humans, such that the majority of the tumor blood supply arises from the hepatic artery and not the portal vein. Differences in blood supply between normal hepatic parenchyma and hepatic tumors might be exploited by developing selective tumor therapies such as arterial embolization or chemoembolization that largely spare normal liver tissue. Further investigation is warranted.

Hepatocyte nuclear factor-1 α inactivated hepatocellular adenomas in patient with congenital absence of the portal vein: a case report.

Hepatocellular adenomas (HCAs) have been recognized recently as a heterogeneous group, and are subclassified according to genotype as well as morphological characteristics. We report a case of a 35-year-old Japanese woman who exhibited hepatocyte nuclear factor (HNF)-1α-inactivated HCA in the background of the congenital absence of the portal vein (CAPV). On a dynamic contrast computed tomography (CT) scan, the hypovascular tumor enlarged from 1 cm to 3 cm and another tumor emerged in the course of 7 years. Because the possibility of hepatocellular carcinoma (HCC) with multiple metastases was not excluded, partial hepatectomy was performed. On a cut section, two well-demarcated tumors were observed and one tumor had a central fibrous scar. The histological features of these tumors were similar to those of focal nodular hyperplasia (FNH) with a central scar and HCA; however, these tumors were diagnosed as HNF-1α-inactivated HCA by immunohistochemistry according to the criteria of the current World Health Organization (WHO) classification. In non-tumorous liver tissue, an abnormal architecture of the vessels and a vague nodular appearance of lobuli were observed, which were likely to be those of nodular regenerated hyperplasia (NRH). We discuss its pathogenesis and relationship with CAPV.

[New aspects in sonography of the liver]. / Neue Horizonte bei der Lebersonographie.

Ultrasound-based technologies are competing more and more success-fully against computerized tomography and magnetic resonance based imaging procedures. This thanks to technological improvements as well as accumulating evidence, stemming from properly conducted controlled clinical studies. The reduced cost and radiation safety issues are additional arguments in its favor. This article reviews new developments in ultrasound medicine as applied to the liver. Emphasis lies on new data related to contrast-ultrasound (Sulphur Hexafluoride SonoVue®) which allows a dynamic analysis of liver perfusion and hence improved characterization of focal liver lesions, such as metastases of extrahepatic tumors, regenerative nodules in patients with liver cirrhosis, focal nodular hyperplasia, hepatocellular carcinoma, liver hemangioma, liver adenoma and or focal hypo-respectively hypersteatosis. This article also deals with important new techniques, which allow assessment of liver stiffness such as transient elastography (Fibroscan), ARFI (Acoustic Radiation Force Impulse) or real-time-tissue elastography. These new techniques will help us to assess and quantify the levels of liver steatosis with more precision and permit accurate follow-up measurements.

Liver tumor characterization--comments and illustrations regarding guidelines.

Contrast-enhanced ultrasound (CEUS) is a well established diagnostic imaging technique for a variety of indications and applications. One of the most important applications is in the liver where it is frequently a first-line technique for the detection and diagnosis (characterization) of focal liver lesions (FLLs). In this setting the accurate differentiation of benign lesions from malignant lesions is critical to ensure that the patient undergoes the appropriate therapeutic option. In this article the role of CEUS in the characterization of FLLs is described on the basis of recently published guidelines, in particular in terms of the enhancement patterns of the most common FLLs, e. g. hemangioma, focal nodular hyperplasia, hepatocellular adenoma and their differentiation from malignant lesions.

A pictorial review of benign hepatocellular nodular lesions: comprehensive radiological assessment incorporating the concept of anomalous portal tract syndrome.

BACKGROUND/PURPOSE: Although the pathological categorization system advocated by the International Working Party (IWP) on Terminology has been helpful in categorizing benign hepatocellular lesions, the diverse clinicopathological features of the lesions still cause confusion of diagnosis in clinical settings. Recently, an integrated disease concept termed "anomalous portal tract syndrome" (APTS) has been proposed as a congenital anomaly of the portal tract, being a single unifying etiological factor underlying the disorder. In this article, we discuss the radiological features of benign nodular hepatocellular lesions incorporated in the concept of APTS. METHODS: We systematically reviewed the literature on benign hepatocellular lesions based on the concept of APTS, as well as standard IWP terminology. For this pictorial review, we selected six representative cases and assessed the radiological features of the cases based on the concept of APTS. RESULTS: The comprehensive assessment based on APTS enabled the systematic categorization of benign hepatocellular lesions, including nodular regenerative hyperplasia, large regenerative nodules, partial nodular transformation, focal nodular hyperplasia, and hepatocellular adenoma, and was helpful in understanding the overlapping features of these lesions. CONCLUSIONS: Although the disease concept of APTS is still evolving, it is nonetheless helpful in comprehensively understanding the clinicopathological and radiological features of various benign hepatocellular lesions.

Molecular characterization of the vascular features of focal nodular hyperplasia and hepatocellular adenoma: a role for angiopoietin-1.

UNLABELLED: Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are two hepatic nodular lesions of different etiologies. FNH, a polyclonal lesion, is assumed to be a regenerative reaction following a vascular injury, whereas HCA is a monoclonal, benign neoplastic lesion. In addition to features that are predominantly found in either FNH or HCA (e.g., dystrophic vessels in FNH and single arteries in HCA), FNH and HCA share morphological vascular abnormalities such as dilated sinusoids. We hypothesized that these anomalous vascular features are associated with altered expression of growth factors involved in vascular remodeling. This was based on reports of morphologically abnormal hepatic vasculature and nodular lesions in transgenic models of hepatocytic overexpression of angiopoietin-1 (Ang-1), a member of the angiopoietin family, which is crucially involved in vascular morphogenesis and homeostasis. We investigated gene and protein expression of members of the angiopoietin system and vascular endothelial growth factor A (VEGF-A) and its receptors in 9 FNH samples, 13 HCA samples, and 9 histologically normal livers. In comparison with normal samples, a significant increase in Ang-1 was found in FNH (P < 0.01) and HCA (P < 0.05), whereas no significant changes in Ang-2, receptor tyrosine kinase with immunoglobulin-like and EGF-like domains 2, VEGF-A, or vascular endothelial growth factor receptor 2 (VEGFR-2) were observed. CONCLUSION: Because of the different etiological contexts of a preceding vascular injury in FNH and a neoplastic growth in HCA, Ang-1 might exert different effects on the vasculature in these lesions. In FNH, it could predominantly stimulate recruitment of myofibroblasts and result in dystrophic vessels, whereas in HCA, it may drive vascular remodeling that produces enlarged vessels and arterial sprouting that generates single arteries.

Necrosis of a large hepatic tumor after hemorrhage and subsequent selective arterial embolization.

This case report describes a young female patient presenting with acute intra-abdominal hemorrhage originating from a large tumor in the liver, most likely a hepatocellular adenoma. The bleeding was stopped by selective embolization of right hepatic artery branches. Subsequently, partial hepatectomy was performed after 6 mo. Macro- and microscopic examination showed complete necrosis and absence of tumorous tissue. The patient was discharged without complications, and subsequent follow-up until 22 mo after resection did not reveal any new lesions in the liver. This case emphasizes the significance of selective arterial embolization in the management of bleeding liver tumors and questions the need for (partial) hepatectomy after this procedure in selective cases.

[Three-dimensional reconstruction and image fusion between liver focal lesions and dynamic contrast-enhanced magnetic resonance angiography].

BACKGROUND & OBJECTIVES: Identifying the correlation of focal lesions to the liver vessel system is a key factor in selecting treatment patterns for focal hepatic diseases. This study was to evaluate the feasibility of 3-dimensional reconstruction and the fusion image between the 3-dimensional dynamic contrast-enhanced magnetic resonance angiography (3D DCE MRA) and the focal hepatic lesions, and further, explore the clinical application of this method. METHODS: 3D DCE-MRA and conventional magnetic resonance imaging (MRI) were performed. The angiography and focal hepatic lesions were reconstructed with maximum intensity projection (MIP) and surface shaded display (SSD), and then fused together. Of the 25 cases with evaluable images, 2 were hemangioma, 3 were focal nodular hyperplasia, 1 was hepatocellular adenoma, 2 were macroregenerative nodule, 2 were hepatobiliary cystadenocarcinoma, and 17 were hepatocellular carcinoma; 21 were confirmed by operation resection, and 4 received digital subtraction angiography (DSA). RESULTS: The anatomic relationship between the lesions and the vessels were well shown. Of the 27 cases, 5 showed normal vessel branching, 6 showed feeding arteries from the hepatic artery, 11 showed compressed and shifted trunks of the vessels, 6 showed tumor invaded vessels, and 11 showed the tumor embolism in the portal vein or the inferior vena cave; 9 also showed MRI signs of portal hypertension. MIP was prior to SSD in demonstrating small branches of the hepatic vessels. CONCLUSION: The 3-dimensional reconstruction and fusion images between 3D DCE-MRA and the focal hepatic lesions by using MIP and SSD can easily display the anatomic relationship between the focal hepatic lesions and the hepatic vessels, and thus can help the surgeons to localize lesions, minimize operating time and decide the extent of surgical resection.

Clinical, morphologic, and molecular features defining so-called telangiectatic focal nodular hyperplasias of the liver.

BACKGROUND & AIMS: Telangiectatic focal nodular hyperplasia (TFNH) of the liver is generally believed to belong to the focal nodular hyperplasia (FNH) family. The aim of this study was to use molecular markers, in addition to morphologic features, to better characterize TFNH. METHODS: Thirteen patients with TFNH were compared with 28 patients with FNH and 17 patients with hepatocellular adenoma. Full clinical and morphologic data were analyzed. Molecular markers included determination of clonality by examining the active X chromosome, genome-wide allelotyping, a search for hepatocyte nuclear factor 1alpha (HNF1alpha) mutations, and determination of ANGPT1/ANGPT2 transcript levels. RESULTS: No clinical differences were evident between patients with TFNH and adenoma; in particular, bleeding was observed in 77% and 53% of the cases, respectively. Patients with TFNH were more likely to experience nodule recurrence and the presence of multiple nodules than those with either FNH or adenoma. All TFNH and adenoma samples that were available for analysis were monoclonal, in contrast to 40% of the FNH samples. Chromosome losses confirmed monoclonality and were significantly less frequent in TFNH and FNH (22% and 26%) than in adenoma (53%). HNF1alpha mutations were found exclusively in half of the adenomas. ANGPT2 was overexpressed in TFNH and down-regulated in adenoma (P < .01) and FNH (P < .0005). CONCLUSIONS: TFNHs are monoclonal lesions frequently subject to bleeding that are similar to adenomas not carrying HNF1alpha mutations and require a similar type of treatment. However, morphologic and molecular data support the hypothesis that TFNH is a separate entity.

Hepatic adenomatous hyperplasia with hyperattenuation on CT during arterial portography: a case report.

We report a 72-year-old man who was admitted to our department with multiple nodules of hepatocellular carcinoma (HCC) in a cirrhotic liver because of HCV infection. Unlike most of the nodules, one in segment 2 (S2) showed hypoattenuation on computed tomography (CT) during hepatic arteriography (CTA), and hyperattenuation on CT during arterial portography (CTAP). Fine needle aspiration biopsy of the nodule established the diagnosis of hepatic adenomatous hyperplasia. Why the S2 nodule showed hyperattenuation on CTAP is not clear. Two possibilities are considered: i) greater portal blood flow into the nodule than into the surrounding cirrhotic parenchyma, ii) existence of a period during the course of hepatocarcinogenesis when the portal blood flow into the nodule is higher in density on CTAP.

Understanding and optimizing use of contrast material for CT of the liver.

Improvements in CT technology have dramatically increased our ability to detect and diagnose liver abnormalities, particularly neoplastic disease. Because of the high prevalence of liver disease in patients referred for abdominal CT examinations, contrast administration and scanning techniques are usually optimized for detection of liver disease on abdominal CT scans. A wide variety of contrast techniques can be used to evaluate the liver, and it is important to understand both the rationale behind each technique and the impact on the quality of the examination when one deviates from these techniques. In addition, the timing of contrast administration and scan acquisition has become critical, and improper timing can cause lesions that are easily visualized to be obscured. This article reviews principles of lesion detection and the effects of various contrast techniques on lesion visualization.

Diagnostic value of color Doppler sonography in primary liver tumors--a trend study.

In order to investigate the diagnostic value in differential diagnosis of primary liver tumors, color Doppler sonography was used preoperatively in 30 patients. Without difference, tumor hypervascularization was found in patients with hepatocellular carcinoma (2 of 4), cholangiocellular carcinoma (4 of 4), hemangioma (3 of 8), focal nodular hyperplasia (8 of 8), adenoma (3 of 4), and neuroendocrine tumor (n = 1). No vascular signal could be detected in 1 case of adenomatous hyperplasia and 2 cases of hepatocellular carcinoma, one after previous chemoembolization. Hemangioma appeared hypo- or even avascular in 5 of 8 patients. Therefore, according to our experience, the yield of color Doppler sonography is rather low for differential diagnosis and prediction of the tumor dignity. With regard to the surgical procedure, valuable information about tumor extension can be obtained particularly in central lesions close to hilar structures or liver vein confluence. Further indications result from follow-up of tumor vascularization after chemoembolization and chemotherapy.