The Thread and Streak Sign

Management of Portal vein Thrombosis in Cirrhosis

Portal vein thrombosis (PVT) is one of the common complications of cirrhosis. The incidence of PVT correlates with liver disease severity-higher incidence in patients with Child-Turcotte-Pugh (CTP) C, large spontaneous portosystemic shunts, hepatofugal portal flow, and in the presence of hepatocellular carcinoma. PVT may worsen ascites, increase the risk and poor control of variceal bleeding. The occurrence of PVT may increase morbidity and lower survival after a liver transplant. Using statins prevents the occurrence of PVT, whereas beta-blockers may aggravate its occurrence. Cross-sectional imaging is mandatory for the precise diagnosis and classification of PVT. Symptomatic, occlusive PVT and candidacy for liver transplantation are the main indications for anticoagulation. Vitamin K antagonists, low-molecular-weight heparin, and newer anticoagulants are effective and safe in cirrhosis. Direct-acting oral anticoagulants are agents of choice in early cirrhosis (CTP A, B). The duration of anticoagulant therapy, predictors of response, and management of complications of cirrhosis while on therapy require in-depth knowledge and individualized treatment. Transjugular intrahepatic porto-systemic shunt can be considered in nonresponsive cases or when anticoagulants are contraindicated. This manuscript reviews the latest updated knowledge about managing PVT in cirrhosis.

Transarterial Therapy for Hepatocellular Carcinoma Invading the Bile Duct

Hepatocellular carcinoma invading the bile duct (bile duct tumor thrombus) is an unfavorable condition. Although overall survival following surgical resection among patients with hepatocellular carcinoma with bile duct tumor thrombus is significantly better than that among those treated with transarterial chemoembolization or chemotherapy, surgical resection can be indicated for selected patients. Additionally, systemic therapy is indicated only for patients with Child-Pugh class A. Therefore, transarterial therapy plays an essential role in the treatment of bile duct tumor thrombus. Transarterial chemoembolization with iodized oil and gelatin sponge particles is an established first-line transarterial treatment that can necrotize most bile duct tumor thrombi. However, we should pay attention to symptoms caused by intraductal hemorrhage during transarterial chemoembolization and the sloughing of necrotized bile duct tumor thrombi.

Diffuse infiltrative hepatocellular carcinoma: Multimodality imaging manifestations

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer, being the third most common cause of cancer-related death globally. HCC most frequently develops in the context of hepatic cirrhosis. HCC can manifest as various morphologic subtypes. Each pattern exhibits distinct behaviors in terms of imaging features, disease progression, response to therapy, and prognosis. While the nodular pattern is the most frequent subtype, infiltrative HCC is the least prevalent and makes up about 8%-20% of all HCC cases. Infiltrative HCC manifests as small tumor nodules that often spread across the entire liver or across a hepatic segment/lobe and is not identified as a focal tumor. On ultrasonography, infiltrative HCC presents as a markedly heterogeneous area with ill-defined echotexture, making it difficult to distinguish from background hepatic cirrhosis. On magnetic resonance imaging (MRI), infiltrating HCC typically manifests as a mild, poorly defined hepatic region with heterogeneous or homogenous aberrant signal intensity. Specifically, on T1-weighted MRI scans, infiltrating HCC frequently appears as largely hypointense and typically homogenous and mildly to moderately hyperintense on T2-weighted imaging. Infiltrative HCC frequently lacks a clearly defined boundary on cross-sectional imaging and can consequently fade into the background of the cirrhotic liver. As a result, infiltrating HCC is frequently not discovered until an advanced stage and has an associated poor prognosis. Thus, understanding imaging features associated with infiltrative HCC diagnosis is crucial for abdominal radiologists to ensure effective and timely care. We herein review imaging characteristics of infiltrative HCC.

Current Imaging Diagnosis of Hepatocellular Carcinoma

Simple Summary

The role of imaging in the management of hepatocellular carcinoma (HCC) has significantly evolved and expanded beyond the plain radiological confirmation of the tumor based on the typical appearance in a multiphase contrast-enhanced CT or MRI examination. The introduction of hepatobiliary contrast agents has enabled the diagnosis of hepatocarcinogenesis at earlier stages, while the application of ultrasound contrast agents has drastically upgraded the role of ultrasound in the diagnostic algorithms. Newer quantitative techniques assessing blood perfusion on CT and MRI not only allow earlier diagnosis and confident differentiation from other lesions, but they also provide biomarkers for the evaluation of treatment response. As distinct HCC subtypes are identified, their correlation with specific imaging features holds great promise for estimating tumor aggressiveness and prognosis. This review presents the current role of imaging and underlines its critical role in the successful management of patients with HCC.

Abstract

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.

Portal vein thrombosis in patients with chronic liver diseases: From conventional to quantitative imaging

Portal vein thrombosis is a pathological condition characterized by the lumen occlusion of the portal vein and its intrahepatic branches, commonly associated to chronic liver diseases. Portal vein thrombosis is often asymptomatic and discovered as an incidental finding in the follow-up of chronic hepatopathy. Imaging plays a pivotal role in the detection and characterization of portal vein thrombosis in patients with hepatocellular carcinoma. Ultrasound and Color-Doppler ultrasound are usually the first-line imaging modalities for its detection, but they have limits related to operator-experience, patient size, meteorism and the restrained field-of view. Unenhanced cross-sectional imaging doesn't provide specific signs of portal vein thrombosis except under certain specific circumstances. Conventional contrast-enhanced imaging can depict portal vein thrombosis as an endoluminal filling defect best detected in venous phase and can differentiate between non-neoplastic and neoplastic thrombus based on the contrast enhanced uptake, but not always rule-out the malignant nature. Functional and quantitative imaging techniques and software seem to be more accurate. The purpose of this work is to provide the reader with an accurate overview focused on the main imaging features of portal vein thrombosis.

Benign and malignant mimickers of infiltrative hepatocellular carcinoma: tips and tricks for differential diagnosis on CT and MRI

Hepatocellular carcinoma (HCC) may have an infiltrative appearance in about 8-20% of cases. Infiltrative HCC can be a challenging diagnosis and it is associated with the worst overall survival among HCC patients. Infiltrative HCC is characterized by the spread of multiple minute nodules throughout the liver, without a dominant one, ultimately resulting into macrovascular invasion. On CT and MRI, infiltrative HCC appears as an ill-defined, large mass, with variable degree of enhancement, and satellite neoplastic nodules in up to 52% of patients. On MRI, it may show restriction on diffusion weighted imaging, hyperintensity on T2- and hypointensity on T1-weighted images, and, if hepatobiliary agent is used, hypointensity on hepatobiliary phase. Infiltrative HCC must be differentiated from other liver diseases, such as focal confluent fibrosis, steatosis, amyloidosis, vascular disorders of the liver, cholangiocarcinoma, and diffuse metastatic disease. In cirrhotic patients, the identification of vascular tumor invasion of the portal vein and its differentiation from bland thrombosis is of utmost importance for patient management. On contrast enhanced CT and MRI, portal vein tumor thrombosis appears as an enhancing thrombus within the portal vein, close to the main tumor and results into vein enlargement. The aim of this pictorial review is to show CT and MRI features that allow the diagnosis of infiltrative HCC and portal vein tumor thrombosis. A particular point of interest includes the tips and tricks for differential diagnosis with potential mimickers of infiltrative HCC.

Different patterns of hepatocellular carcinoma-related malign thrombosis in 18F-FDG PET/CT

Tumor thrombus is an intravascular malign tumor extension that may occur in various types of cancer. Hepatocellular carcinomas (HCC) are common causes of malign thrombus. The presence of a malign thrombus due to HCC has a dismal prognosis, which affects treatment choices. We present three cases of tumor thrombi due to advanced HCC detected by ¹⁸F-FDG PET/CT.

Tumor thrombus: incidence, imaging, prognosis and treatment

Intravascular tumor extension, also known as tumor thrombus, can occur in many different types of cancer. Those with the highest proclivity include Wilm's tumor, renal cell carcinoma (RCC), adrenal cortical carcinoma (ACC) and hepatocellular carcinoma (HCC). The presence of tumor thrombus markedly worsens prognosis and impacts treatment approach. Imaging plays a key role in its diagnosis. Endovascular methods also play a large role in treatment.

Clinical implications for imaging of vascular invasion in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second largest cause of cancer mortality in the world, with vascular invasion being one of the most important prognostic factors. HCC with tumor thrombus was traditionally considered to have very limited treatment options. However, multiple promising treatment strategies have emerged in recent years, with diagnostic and interventional radiologists playing a major role in patient management. We provide a comprehensive update on the diagnosis and management of HCC with vascular invasion and the role of the radiologist in this condition.

Tumoral pulmonary emboli from angioinvasive hepatocellular carcinoma

Tumoral pulmonary emboli from hepatocellular carcinoma (HCC) have rarely been described, although invasion of the portal and hepatic venous systems is a well-known complication. HCC originating in a noncirrhotic liver in the absence of chronic hepatitis B infection is also uncommon. We present a case of a patient with chronic hepatitis C infection without hepatic cirrhosis who developed angioinvasive HCC with intracardiac extension and tumoral pulmonary emboli. Differential considerations, including combined HCC-cholangiocarcinoma, other hepatic mesenchymal tumors, and metastasis, are discussed. Owing to poor prognosis, no resection was attempted. Autopsy was performed because of the unusual clinical presentation, and immunohistochemistry of the hepatic tumor, the intracardiac extension, and the pulmonary emboli were concordant with hepatocellular origin. Even though definitive diagnosis may not affect patient outcome, it is important for radiologists and clinicians to be aware that angioinvasive HCC may arise in the absence of cirrhosis.

Imaging in clinical decision-making for portal vein thrombosis

Thrombosis of the portal venous system is a frequent and potentially life-threatening condition that can take place in a number of different clinical settings including liver cirrhosis, hepatocellular carcinoma, other solid tumours, abdominal septic foci, acute pancreatitis, haematological malignancies and congenital or acquired prothrombotic disorders. Clinical decision-making in patients with thrombosis of the portal venous system is a particularly complex process owing to the heterogeneity of the population affected by this condition and the lack of high-quality evidence from randomized controlled trials for the use of anticoagulation therapy in these patients. This Review discusses the available data regarding how imaging can provide assistance to physicians involved in this decision-making process in different clinical settings. A flowchart illustrating how to use imaging in this setting, based on current evidence and on the experience of the Vascular Liver Diseases Group of the Hospital Clinic in Barcelona, is also presented.

Radiological assessment of hepatic vein invasion by hepatocellular carcinoma using combined computed tomography hepatic arteriography and computed tomography arterial portography

PURPOSE

The aim of this study was to elucidate computed tomography hepatic arteriography (CTHA) and CT arterial portography (CTAP) findings characteristic of hepatocellular carcinoma (HCC) with large hepatic venous invasion (HVI) and then to examine whether the presence of minute HVI can be diagnosed based on each finding.

MATERIALS AND METHODS

Combined CTHA and CTAP of 106 HCCs were examined. Two radiologists analyzed the radiological findings of five nodules with large HVI (group vv2). The remaining 101 nodules were classified into two groups: group vv1, positive minute HVI; group vv0, negative HVI. They examined whether each finding observed in group vv2 could be detected in groups vv1 and vv0.

RESULTS

Analysis of group vv2 identified (a) tumor thrombus, (b) early inflow of the contrast into the hepatic vein proximal to the invaded site, and (c) partially decreased portal venous flow in the peripheral parenchyma subject to the involved hepatic vein. Findings (b) and (c) were observed in 16% of group vv1. A significant difference in frequency of finding (c) was obtained between groups vv1 and vv0. The positive and negative predictive values of finding (c) were 66.7% and 77.9%, respectively.

CONCLUSION

Findings (b) and (c), especially the latter, may partly contribute to the radiological diagnosis of minute HVI.