VEGFR-2 expression in HCC, dysplastic and regenerative liver nodules, and correlation with pre-biopsy Dynamic Contrast Enhanced CT

Combined clinical features and MRI parameters for the prediction of VEGFR2 in hepatocellular carcinoma patients

Purpose

To develop a prediction model for estimating the expression of vascular endothelial growth factor receptor 2 (VEGFR2) in hepatocellular carcinoma (HCC) patients using clinical features and the contrast-enhanced MRI Liver Imaging Reporting and Data System (LI-RADS).

Methods

A total of 206 HCC patients were subjected to preoperative contrast-enhanced MRI, radical resection, and VEGFR2 immunohistochemistry labeling. The intensity of VEGFR2 expression was used to split patients into either the positive group or the negative group. For continuous data, the Mann-Whitney U test was employed, and for categorical variables, the χ2 test was utilized.

Results

VEGFR2-positivity was identified in 41.7% (86/206) of the patients. VEGFR2-positive HCCs were confirmed by higher serum alpha-fetoprotein (AFP) levels, larger tumor dimensions (either on MRI or upon final pathology), and a higher LI-RADS score (all p < 0.001). LI-RADS scores and AFP levels were independent predictors for high VEGFR2 expression. These two parameters were used to establish a VEGFR2-positive risk nomogram, which was validated to possess both good discrimination and calibration. The area under the curve was 0.830 (sensitivity 83.6%, specificity 72.5%) and the mean absolute error was 0.021. The threshold probabilities ranged between 0.07 and 0.95, and usage of the model contributed net benefits.

Conclusion

A nomogram including clinical features and contrast-enhanced MRI parameters was developed and was demonstrably effective at predicting VEGFR2 expression in HCC patients.

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.

Rim Enhancement after Technically Successful Transarterial Chemoembolization in Hepatocellular Carcinoma: A Potential Mimic of Incomplete Embolization or Reactive Hyperemia?

Contrast enhancement at the margins/rim of embolization areas in hepatocellular-carcinoma (HCC) lesions treated with transarterial chemoembolization (TACE) might be an early prognostic indicator for HCC recurrence. The aim of this study was to evaluate the predictive value of rim perfusion for TACE recurrence as determined by perfusion CT (PCT). A total of 52 patients (65.6 ± 9.3 years) underwent PCT directly before, immediately after (within 48 h) and at follow-up (95.3 ± 12.5 days) after TACE. Arterial-liver perfusion (ALP), portal-venous perfusion (PVP) and hepatic-perfusion index (HPI) were evaluated in normal liver parenchyma, and on the embolization rim as well as the tumor bed. A total of 42 lesions were successfully treated, and PCT measurements showed no residually vascularized tumor areas. Embolization was not entirely successful in 10 patients with remaining arterialized focal nodular areas (ALP 34.7 ± 10.1 vs. 4.4 ± 5.3 mL/100 mL/min, p < 0.0001). Perfusion values at the TACE rim were lower in responders compared to normal adjacent liver parenchyma and edges of incompletely embolized tumors (ALP liver 16.3 ± 10.1 mL/100 mL/min, rim responder 8.8 ± 8.7 mL/100 mL/min, rim non-responder 23.4 ± 8.6 mL/100 mL/min, p = 0.005). At follow-up, local tumor relapse was observed in 17/42, and 15/42 showed no recurrence (ALP 39.1 ± 10.1 mL/100 mL/min vs. 10.0 ± 7.4 mL/100 mL/min, p = 0.0008); four patients had de novo disseminated disease and six patients were lost in follow-up. Rim perfusion was lower compared to adjacent recurring HCC and not different between groups. HCC lesions showed no rim perfusion after TACE, neither immediately after nor at follow-up at three months, both for mid-term responders and mid-term relapsing HCCs, indicating that rim enhancement is not a sign of reactive hyperemia and not predictive of early HCC recurrence.

Clinical features and diagnostic and therapeutic strategies of hepatic dysplastic nodules

Hepatic dysplastic nodules (DNs) are a group of neoplastic lesions with a diameter of more than 1 cm that belong to precancerous lesions, with abnormal cytoplasm and cells but without malignant basis in histology. Hepatic DNs lack typical tumor markers and clinical symptoms, and their clinical diagnosis relys mainly on imaging or/and tissue pathological examination. Thanks to the further research on the pathogenesis of hepatic DNs and the development of imaging technology, the combination of medical history, various examinationss, individual tumor markers, and imaging and histopathology techniques can significantly improve the early detection and diagnosis accuracy for hepatic DNs, and reduce the rate of missed and false diagnosis. Due to the potential malignancy risk of hepatic DNs, intervention measures should be carried out on hepatic DNs at all stages, in order to block the transformation process of DNs into hepatocellular carcinoma (HCC), which is of great clinical significance to reduce the incidence and mortality of HCC.

Microvessel density and angiogenesis in primary hepatic malignancies: Differential expression of CD31 and VEGFR-2 in hepatocellular carcinoma and intrahepatic cholangiocarcinoma

BACKGROUND

Microvessel density is an indicator of tumor-driven neoangiogenesis. Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) have distinct vascular patterns, which are also reflected in their imaging characteristics. Since a significant proportion of HCC are treated without biopsy confirmation, it is essential to discriminate HCC and ICC radiologically. The aim of our study was therefore to compare microvessel density and expression of VEGFR-2 in HCC and ICC, since these data may ultimately help us to better understand their imaging characteristics. Whereas CD31 documents vessel density, VEGFR-2 expression is an indicator of tumor-related neoangiogenesis.

METHODS

CD31 and VEGFR-2 expressing microvessels were quantified on tissue microarrays of 95 resection specimens of HCC and 47 cases of ICC. Microvessel density was evaluated by counting immuno-reactive vascular structures both within the tumor and adjacent liver control tissue, respectively. Further 16 cases of ICC were immunostained for CD31 and VEGFR-2 on full sections.

RESULTS

The frequency of VEGFR-2 (46.2/HPF; range 0-150) and CD31 (61.2/HPF; range 2.6-140) expressing vascular structures was significantly increased in HCC compared to adjacent liver parenchyma (VEGFR-2 33.3/HPF, range 0-87, CD31 21.4/HPF, range 0-78, both p < 0,001). ICC revealed significantly less VEGFR2-positive microvessels (15.4/HPF; range 2-77) compared to matched control tissue (42.3/HPF; range 4.6-109), whereas microvessel density with CD31 was comparable between ICC and adjacent liver (32.1/HPF; range 5.3-78 versus 28.0/HPF; range 5.3-57; p = 0.89). In ICC, the tumor-to-normal microvessel density ratio was 0.38 for VEGFR-2 and 1.24 for CD31. These ratios were nearly identical (VEGFR: 0.38; CD31: 0,97) for the 16 cases of ICC studied on whole sections, confirming the validity of the TMA approach. In contrast, ratios of VEGFR-2 and CD31 in HCC vs. adjacent liver were significantly higher (VEGFR: 2.23; CD31: 6.57). Expression of VEGFR-2 by tumor cells was not observed in any of the cases.

CONCLUSIONS

HCC and ICC differ significantly in their microvessel density, confirming the hypovascular nature of ICC as compared to the hypervascularity of HCC. Of note, inverse tumor-to-normal ratios of microvascular VEGFR-2 expression between the two neoplasms indicate distinct features of neoangiogenesis. Whether these differences can be exploited for improvements in imaging of hepatic tumors and may play a role for anti-angiogenic treatment strategies requires further studies.

Multiparametric imaging for detection and characterization of hepatocellular carcinoma using gadoxetic acid-enhanced MRI and perfusion-CT: which parameters work best?

Background

MRI and perfusion-CT (PCT) are both useful imaging techniques for detection and characterization of liver lesions. The aim of this study was to compare the diagnostic accuracy of imaging parameters derived from PCT and gadoxetic acid-enhanced MRI in patients with hepatocellular carcinoma (HCC).

Methods

36 patients with liver cirrhosis and a total of 67 lesions referred to our hospital for multi-parametric diagnosis of HCC-suspected liver lesions in the setting of liver cirrhosis were prospectively enrolled and underwent PCT and MRI. HCC diagnosis was confirmed either by histology (n = 60) or interval growth (n = 7). For PCT, mean/max blood flow (BF), blood volume (BV), k-trans, arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI) were quantified. Two readers identified the lesions based on single maps each being blinded to the number of lesions.

MRI-protocol included fat-suppressed T1w-VIBE sequences obtained before, 2, 5, 10 and 20 min after the injection of gadoxetic acid as well as non-enhanced coronal HASTE, axial T1w-VIBE, fat-suppressed T2w-TSE and DWI. Quantitative analysis was performed using enhancement ratios between tumor and liver parenchyma for post-contrast in the hepatobiliary phase (RIR_HB), arterial (ER_a) and late-venous (ER_v) phases as well as signal intensity ratios (liver/parenchyma) on T1w (RIR_T1) and T2w (RIR_T2).

Results

In PCT analysis, all lesions exhibited high BF_max values (63–250 mL/100 g tissue) and were visible on HPI maps with high degrees of arterial blood supply of (HPI > 96%).

In MRI, RIR_HB was negative in 8/67. 12/67 HCCs were missed on DWI. 46/67 HCCs showed wash-in and 47/67 HCC showed wash-out of contrast agent. 6/67 HCCs were missed on T1w and 11/67 were missed on T2w-sequences when analyzed separately, while analysis of multiparametric MRI combining typical enhancement pattern, visibility on hepatobiliary phase and T1w-images the same number of lesions as PCT irrespective of their size (1–19 cm) were detected. Quantification of early enhancement by ER_a or ER_v did not improve detection rates.

Conclusions

Perfusion-CT and gadoxetic acid-enhanced MRI were comparable in detecting HCC lesions. For PCT a mean HPI > 96% proved to be a very robust parameter for detection and characterization of HCC.