Venous invasion by hepatic tumors: imaging appearance and implications for management

Advances in Understanding Hepatocellular Carcinoma Vasculature: Implications for Diagnosis, Prognostication, and Treatment

Hepatocellular carcinoma (HCC) progresses through multiple stages of hepatocarcinogenesis, with each stage characterized by specific changes in vascular supply, drainage, and microvascular structure. These vascular changes significantly influence the imaging findings of HCC, enabling non-invasive diagnosis. Vascular changes in HCC are closely related to aggressive histological characteristics and treatment responses. Venous drainage from the tumor toward the portal vein in the surrounding liver facilitates vascular invasion, and the unique microvascular pattern of vessels that encapsulate the tumor cluster (known as a VETC pattern) promotes vascular invasion and metastasis. Systemic treatments for HCC, which are increasingly being used, primarily target angiogenesis and immune checkpoint pathways, which are closely intertwined. By understanding the complex relationship between histopathological vascular changes in hepatocarcinogenesis and their implications for imaging findings, radiologists can enhance the accuracy of imaging diagnosis and improve the prediction of prognosis and treatment response. This, in turn, will ultimately lead to better patient care.

Refining MRI-based criteria for portal vein invasion in hepatocellular carcinoma: improving sensitivity beyond portal vein tumor thrombosis

PURPOSE

To investigate the imaging features indicating portal vein invasion (PVI) of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI and to create more accurate diagnostic criteria than the presence of portal vein tumor thrombosis (PVTT) on MRI.

METHODS

This retrospective study included patients with surgically resected HCC larger than 5 cm, and the presence of PVI was investigated. On MRI, we evaluated the image findings of portal vein occlusion, the parenchymal signal change caused by hemodynamic alterations of the portal vein, and their combination showing the highest odds ratio (OR) to define the diagnostic criteria for radiological PVI detection (rPVI criteria). The diagnostic performance and recurrence-free survival were compared between the rPVI criteria and the presence of PVTT using McNemar's test and Kaplan-Meier method, respectively. Interobserver agreement was evaluated using Cohen's weighted ĸ statistics.

RESULTS

Of 189 enrolled patients, 25 (13.2%) had PVI on histology. To diagnose PVI on MRI, either peripheral wedge-shaped arterial peritumoral hyperemia with an abrupt cut-off of a portal vein or the presence of PVTT had the highest OR (41.67, p < 0.001). The sensitivity of PVI was significantly increased under this diagnostic criterion (64.0% to 88.0%; p = 0.031) with comparable accuracy (95.2% vs. 94.7%; p > 0.999). In terms of recurrence-free survival, the patient group with rPVI was significantly worse (p = 0.017) compared with the patients without rPVI. Interobserver agreement of radiologic findings was substantial (ĸ = 0.64).

CONCLUSION

Diagnostic criteria for radiologically PVI detection increase the sensitivity more than the only presence of PVTT.

Inter-observer agreement and accuracy of LI-RADS v2018 for differentiating tumor in vein from bland thrombus using gadoxetic acid-enhanced magnetic resonance imaging

PURPOSE

To assess inter-observer agreement and accuracy of LI-RADS v2018 for differentiating tumor in vein (TIV) from bland thrombus on gadoxetic acid-enhanced magnetic resonance imaging (Gx-MRI). Secondarily, to determine whether a multi-feature model improves accuracy compared to LI-RADS.

METHODS

We retrospectively identified consecutive patients at risk for hepatocellular carcinoma with venous occlusion(s) reported on Gx-MRI. Five radiologists independently classified each occlusion as TIV or bland thrombus using the LI-RADS TIV criterion (enhancing soft tissue in vein). They also evaluated imaging features suggestive of TIV or bland thrombus. Intra-class correlation coefficient (ICC) was calculated for individual features. A multi-feature model was developed based on consensus scores of features with > 5% consensus prevalence and > 0.40 ICC. Sensitivity and specificity of the LI-RADS criterion and of the cross-validated multi-feature model were compared.

RESULTS

Ninety-eight patients with 103 venous occlusions (58 TIV, 45 bland thrombus) were included. The LI-RADS criterion provided 0.63 ICC and, depending on the reader, 0.62-0.93 sensitivity and 0.87-1.00 specificity. Five other features had > 5% consensus prevalence and > 0.40 ICC, including three LI-RADS suggestive features and two non-LI-RADS features. The optimal multi-feature model incorporated the LI-RADS criterion and one LI-RADS suggestive feature (occluded or obscured vein contiguous with malignant parenchymal mass). After cross-validation, the multi-feature model did not improve sensitivity or specificity compared to the LI-RADS criterion (P = 0.23 and 0.25, respectively).

CONCLUSION

Using Gx-MRI, the LI-RADS criterion for TIV provides substantial inter-observer agreement, variable sensitivity, and high specificity for differentiating TIV from bland thrombus. A cross-validated multi-feature model did not improve diagnostic performance.

Radiomics-Based Prediction of Future Portal Vein Tumor Infiltration in Patients with HCC-A Proof-of-Concept Study

Portal vein infiltration (PVI) is a typical complication of HCC. Once diagnosed, it leads to classification as BCLC C with an enormous impact on patient management, as systemic therapies are henceforth recommended. Our aim was to investigate whether radiomics analysis using imaging at initial diagnosis can predict the occurrence of PVI in the course of disease. Between 2008 and 2018, we retrospectively identified 44 patients with HCC and an in-house, multiphase CT scan at initial diagnosis who presented without CT-detectable PVI but developed it in the course of disease. Accounting for size and number of lesions, growth type, arterial enhancement pattern, Child-Pugh stage, AFP levels, and subsequent therapy, we matched 44 patients with HCC who did not develop PVI to those developing PVI in the course of disease (follow-up ended December 2021). After segmentation of the tumor at initial diagnosis and texture analysis, we used LASSO regression to find radiomics features suitable for PVI detection in this matched set. Using an 80:20 split between training and holdout validation dataset, 17 radiomics features remained in the fitted model. Applying the model to the holdout validation dataset, sensitivity to detect occurrence of PVI was 0.78 and specificity was 0.78. Radiomics feature extraction had the ability to detect aggressive HCC morphology likely to result in future PVI. An additional radiomics evaluation at initial diagnosis might be a useful tool to identify patients with HCC at risk for PVI during follow-up benefiting from a closer surveillance.

Tumor in vein (LR-TIV) and liver imaging reporting and data system (LI-RADS) v2018: diagnostic features, pitfalls, prognostic and management implications

Vascular invasion by hepatocellular carcinoma (HCC), also known as tumor in vein (TIV), indicates highly invasive tumor behavior and is also associated with poor outcome. Because a diagnosis of TIV precludes liver transplantation, knowledge of the imaging findings to differentiate between TIV and bland thrombus is key for proper patient management. Prior versions of liver imaging reporting and data system (LI-RADS) included presence of TIV as part of LR-5 criteria. However, even if HCC is the most common liver malignancy associated with TIV, other tumors can have vascular invasion and may occur in cirrhotic patients. For these reasons, in LI-RADS v2017 LR-TIV has been introduced as a new different diagnostic category. The aim of this article is to discuss the diagnostic criteria of LR-TIV according to LI-RADS v2018 and analyze potential pitfalls encountered on daily clinical practice. Indeterminate cases and how to manage them will also be discussed.

Hepatic vein tumor thrombosis in patients with hepatocellular carcinoma: Prevalence and clinical significance

BACKGROUND

There is strong evidence that portal vein tumor thrombosis (PVTT) is associated with poor survival in patients with hepatocellular carcinoma (HCC). However, data regarding the clinical significance of hepatic vein tumor thrombosis (HVTT) is rare, particularly in Western patients.

OBJECTIVE

To determine the HVTT prevalence in a Western patient population and its impact on survival.

METHODS

We included 1310 patients with HCC treated in our tertiary referral center between January 2005 and December 2016. HVTT and PVTT were diagnosed with contrast-enhanced cross-sectional imaging. Overall survival (OS) was calculated starting from the initial HCC diagnosis, and in a second step, starting from the first appearance of vascular invasion.

RESULTS

We observed macrovascular invasion (MVI) in 519 patients who suffered from either isolated HVTT (n = 40), isolated PVTT (n = 352), or both combined (HVTT + PVTT) (n = 127). Calculated from the initial HCC diagnosis, the median OS for patients with isolated HVTT was significantly shorter than that of patients without MVI (13.3 vs. 32.5 months, p < 0.001). Calculated from the first appearance of MVI, the median OS was similar among patients with isolated HVTT (6.5 months), isolated PVTT (5 months), and HVTT + PVTT (5 months). Multivariate analysis confirmed HVTT as an independent risk factor for poor survival.

CONCLUSIONS

HVTT may be more common than typically reported. In most patients, it was accompanied by PVTT. Isolated HVTT occurred less frequently and later than isolated PVTT; however, once developed, it had the same deleterious impact on survival. Therefore, patients with HVTT should be classified as advanced stage of HCC.

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.

Extent of portal vein tumour thrombosis in patients with hepatocellular carcinoma: The more, the worse?

BACKGROUND & AIMS

Portal vein tumour thrombosis (PVTT) has a significant impact on the prognosis of patients with hepatocellular carcinoma (HCC). The degree of PVTT varies from sub-/segmental invasion to complete occlusion of the main trunk. Aim of this study was to evaluate whether the degree of PVTT correlates with prognosis.

METHODS

A total of 1317 patients with HCC treated at our tertiary referral centre between January 2005 and December 2016 were included. PVTT was diagnosed by contrast-enhanced computed tomography or magnetic resonance imaging. The extent of PVTT was documented according to the Liver Cancer Study Group of Japan classification: Vp0 = no PVTT, Vp1 = segmental portal vein invasion, Vp2 = right anterior/posterior portal vein, Vp3 = right/left portal vein and Vp4 = main trunk. Median overall survival (OS) was calculated for each group.

RESULTS

Portal vein tumour thrombosis was present in 484 (36.8%) patients. Median OS without PVTT was 35.7 months, significantly longer than in patients with PVTT (7.2 months, P < 0.001). The patients with PVTT were subclassified as follows: 103 Vp1, 87 Vp2, 143 Vp3 and 151 Vp4. The corresponding median OS yielded 14.6, 9.4, 5.8 and 4.8 months for Vp1-Vp4, respectively (P < 0.001).

CONCLUSIONS

Portal vein tumour thrombosis in patients with HCC is associated with a dismal prognosis. The results indicate an association between the extent of PVTT and OS. However, the extent of PVTT is not that decisive, as even minor PVTT leads to a very poor prognosis. Therefore, meticulous evaluation of cross-sectional imaging is crucial for the clinical management of patients with HCC.

Portal vein thrombosis: What surgeons need to know

KEY POINTS

(a) The lifetime risk of portal vein thrombosis (PVT) is approximately 1%; (b) The portal vein is formed by the union of the splenic and superior mesenteric veins posterior to the pancreas; (c) Imaging modalities most frequently used to diagnose PVT include sonography, computed tomography, and magnetic resonance imaging; (d) Malignancy, hepatic cirrhosis, surgical trauma, and hypercoagulable conditions are the most common risk factors for the development of PVT; (e) PVT eventually leads to the formation of numerous collateral vessels around the thrombosed portal vein; (f) First-line treatment for PVT is therapeutic anticoagulation-it helps prevent the progression of the thrombotic process; (g) Other therapeutic options include surgery and interventional radiographic procedures including mechanical thrombectomy and thrombolysis; (h) Portal biliopathy is a clinicopathologic entity characterized by biliary abnormalities due to portal hypertension secondary to PVT and appears to be more common in cases of extrahepatic PVT.

REPUBLISHED WITH PERMISSION FROM

Quarrie R, Stawicki SP. Portal vein thrombosis: What surgeons need to know. OPUS 12 Scientist 2008;2(3):30-33.