MRI in differentiating malignant versus benign portal vein thrombosis in patients with hepatocellular carcinoma: Value of post contrast imaging with subtraction

Role of contrast-enhanced ultrasound for differentiation of benign vs. malignant portal vein thrombosis in hepatocellular carcinoma - A systematic review a meta-analysis

Introduction/Purpose

Patients with cirrhosis and hepatocellular carcinoma (HCC) can develop both benign and malignant portal vein thrombosis (PVT). Characterising the nature of PVT is important for planning an optimal therapeutic strategy. In the absence of typical findings or contraindications to computed tomography (CT) or magnetic resonance imaging (MRI), contrast-enhanced ultrasound (CEUS) could help in this differentiation. The present meta-analysis aimed to evaluate the performance of CEUS for characterising PVT in patients with HCC.

Methods

Electronic databases of PubMed, Embase and Scopus were searched from inception to 31 December 2022 for studies analysing the role of CEUS in the differentiation of benign and malignant PVT in HCC. Using the bivariate random effect model, pooled sensitivity and specificity were calculated, and the summary receiver operating characteristic (sROC) curve was plotted.

Results

A total of 12 studies with data from 712 patients were included in the meta-analysis. The pooled sensitivity and specificity of CEUS for the diagnosis of tumour in vein were 97.0% (95% CI: 93.0-98.7) and 96.8% (95% CI: 92.1-98.7), respectively, without significant heterogeneity. A sROC curve was plotted, and the area under the receiver operating characteristic was 0.99 (95% CI: 0.98-1.00). Despite the presence of publication bias, sensitivity analysis did not show any change in sensitivity and specificity.

Discussion

Our meta-analysis summarises the accuracy data from 12 studies, including >700 subjects. Contrast-enhanced ultrasound had excellent diagnostic accuracy with pooled sensitivity and specificity of 97.5% (95% CI: 93.5-99.1) and 98.2% (95% CI: 91.5-99.6), respectively, without any significant heterogeneity. Additionally, the pooled positive LR, negative LR and DOR were 54.6 (95% CI: 11.1-25.6), 0.02 (0.01-0.07) and 2186.8 (318.3-15022.2), respectively. A positive result increases the pretest probability of malignant PVT from 50% to 98%, whereas a negative result decreases it from 50% to 2%. Most of the studies included in our meta-analysis used identical techniques and 6-12-month follow-up scans to check for thrombus progression or regression. Our analysis showed no significant heterogeneity in the studies, and area under receiver operating characteristic curve (AUROC) with 95% CI was 1.00 (95% CI: 0.99-1.00). This critical meta-analysis thus propels CEUS to the forefront for differentiating benign from tumoural PVT and suggests routinely using CEUS in patients presenting with HCC and evidence of thrombus on greyscale ultrasound.

Conclusion

Contrast-enhanced ultrasound is an effective diagnostic modality differentiation of benign and malignant PVT in patients with HCC and can be an alternative modality to CT or MRI. Further studies are required to study the role of CEUS as initial diagnostic modality for the characterisation of PVT in HCC.

Multimodality imaging approach in identifying invasive hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the 5th most common neoplasm and the 3rd leading cause of cancer related mortality worldwide. Early stages of the neoplasm may be treated curatively with liver resection or orthotopic liver transplant. However, HCC has a high propensity for vascular and locoregional invasion, which can preclude these treatment options. The portal vein is the most invaded structure, while other regional structures affected include the hepatic vein, inferior vena cava, gallbladder, peritoneum, diaphragm, and the gastrointestinal tract. Management of invasive and advanced stages of HCC includes modalities such as transarterial chemoembolization (TACE), transarterial radioembolization (TARE), and systemic chemotherapy, which are non-curative and focus on relieving tumor burden and slowing progression. A multimodality imaging approach is effective in identifying areas of tumor invasion and distinguishing between bland and tumor thrombi. Due to implications in prognosis and management, it is imperative for radiologists to accurately identify imaging patterns of regional invasion by HCC and to distinguish between bland and tumor thrombus in cases of potential vascular invasion.

Portal vein thrombosis in cirrhosis: A literature review

Portal Vein Thrombosis (PVT), a common complication of advanced liver disease, is defined as an obstruction of the portal vein due to thrombus formation that can extend to the superior mesenteric and splenic veins. It was believed that PVT occurred predominantly due to prothrombotic potential. However, recent studies have shown that decreased blood flow related to portal hypertension appears to increase PVT risk as per Virchow's triad. It is well known that there is a higher incidence of PVTs in cirrhosis with a higher MELD and Child Pugh score. The controversy for management of PVTs in cirrhotics lies in the individualized assessment of risks versus benefits of anticoagulation, since these patients have a complex hemostatic profile with both bleeding and procoagulant propensities. In this review, we will systematically compile the etiology, pathophysiology, clinical features, and management of portal vein thrombosis in cirrhosis.

The clinical value of dual-energy computed tomography and diffusion-weighted imaging in the context of liver cancer: A narrative review

The dual-energy computed tomography (DECT) and diffusion-weighted magnetic resonance imaging (DWI-MRI) are used to diagnose liver cancer. The clinical value of these two examination methods needs to be further summarized. We collected and summarized relevant literature published from 2011 to 2021. The diagnostic performance of DECT was assessed between conventional computed tomography and DWI-MRI. DWI-MRI had a 69% sensitivity for detecting small hepatocellular carcinoma (HCC) lesions and a 60% diagnostic specificity for differentiating between types of HCC lesions. DECT had a sensitivity to small liver lesions (<1 cm) of 69%, and the diagnostic specificity for HCC and metastasis was about 60%. DWI was more sensitive (90.3% vs. 74.9%) and accurate (91.9% vs. 76.9%) in diagnosing HCC compared with conventional MRI sequencing. With the aid of contrast media, DWI-MRI had 90.0% specificity for detecting small HCCs (smaller than 1 cm). Furthermore, DWI-MRI not only provided physicians with valuable diagnostic information but also delivered histological grading information, with 78% accuracy for all benign lesions and 71% for solid lesions. DECT had relatively high sensitivity and required a lower contrast medium dose. With standardized quantitative parameters, it can be an extremely useful tool for HCC surveillance. DWI-MRI is the preferred imaging process as it produces high-contrast images for supporting an early diagnosis (high sensitivity and specificity) and provides histological information using non-ionizing radiation.

Anormal uterin kanama ile seyreden tümör trombüsünün nadir bir nedeni olarak uterin leiomyomatozis

Anormal uterin kanama ile seyreden tümör trombüsünün nadir bir nedeni olarak uterin leiomyomatozis

Portal Vein Thrombosis in Cirrhosis

Patients with cirrhosis of the liver are at high risk of developing portal vein thrombosis (PVT), which has a complex, multifactorial cause. The condition may present with a myriad of symptoms and can occasionally cause severe complications. Contrast-enhanced computed tomography (CT) is the gold standard for the diagnosis of PVT. There are uncertainties regarding the effect on PVT and its treatment outcome in patients with cirrhosis. The main challenge for managing PVT in cirrhosis is analyzing the risk of hemorrhage compared to the risk of thrombus extension leading to complications. All current knowledge regarding non-tumor PVT in cirrhosis, including epidemiology, risk factors, classification, clinical presentation, diagnosis, impact on natural history, and treatment, is discussed in the present article.

MRI diffusion-weighted imaging detects a fresh portal vein thrombus as a high intensity lesion in a patient with a liver transplant: A case report

Portal vein thrombosis is one of the most serious complications after liver transplantation. It is important to determine the age of the thrombus for management of portal vein thrombosis. We present a case report of histologically confirmed heterogenous fresh portal vein thrombus which was depicted heterogenous high signal intensity on magnetic resonance diffusion weighted imaging. The sequence may be a useful imaging tool for detecting fresh thrombus components in the portal vein thrombosis.

Evolution of Nonmalignant Portal Vein Thrombosis in Liver Cirrhosis: A Pictorial Review

Portal vein thrombosis (PVT) is a common complication in liver cirrhosis, especially in advanced cirrhosis. It may be related to a higher risk of liver-related events and liver function deterioration. Imaging examinations can not only provide an accurate diagnosis of PVT, such as the extent of thrombus involvement and the degree of lumen occupied, but also identify the nature of thrombus (i.e., benign/malignant and acute/chronic). Evolution of PVT, mainly including development, recanalization, progression, stability, and recurrence, could also be assessed based on the imaging examinations. This article briefly reviews the pathophysiology, diagnosis, classification, and evolution of PVT with an emphasis on their computed tomography imaging features.

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.

LI-RADS and transplantation: challenges and controversies

Patients with early stage hepatocellular carcinoma (HCC) can be cured by liver transplantation. HCC imaging features on CT or MRI are specific enough to allow for definitive diagnosis and treatment without the need of confirmatory biopsy. When applied to the appropriate at-risk population the Liver Imaging Reporting and Data System (LI-RADS) imaging criteria achieve high specificity and positive predictive value for the diagnosis of HCC. The Organ Procurement and Transplantation Network (OPTN) is the United States organization that aims to assure the adequate and fair distribution of livers across candidates. Given the importance of fair organ allocation, OPTN also provides stringent imaging criteria for the diagnosis of HCC aiming to avoid false positive diagnosis. Although most imaging criteria are identical for both systems, discrepancies between LI-RADS and the current OPTN classification system for HCC diagnosis exists. Main differences include, but are not limited to, the binary approach of OPTN to classify lesions as HCC or not, versus the probabilistic algorithmic approach of LI-RADS, technical and interpretation considerations, and the approach towards treated lesions. The purpose of this article is to highlight the similarities and discrepancies between LI-RADS and the current OPTN criteria for HCC diagnosis and the implications that these differences may have on the management of patients who are transplant candidates.

The ABCD of portal vein thrombosis: a systematic approach

Portal vein thrombosis refers to complete or partial obstruction of the portal venous system, in the intrahepatic or extrahepatic venous tract or even in the splenic or superior mesenteric veins. This common and potentially fatal condition can develop in various clinical contexts, especially those of liver cirrhosis, hepatocellular carcinoma, and other solid tumors. Certain characteristics, such as the time since the onset of the thrombus (acute or chronic), its biology (hematic or tumoral), the presence of collateral vessels, and the magnetic resonance imaging aspects, are important components of a thorough, careful analysis, as well as informing decisions regarding the appropriate therapeutic strategy. Here, we present a brief review of the anatomy of the portal venous system and a systematic approach to analyzing the condition, using a mnemonic (ABCD, for age, biology, collaterals, and diffusion). We discuss the various imaging methods and illustrate our discussion with images selected from the case files archived at our facility.

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. ^©RSNA, 2020.