Imaging of HCC

Liver Imaging Reporting and Data System Contrast-Enhanced US Nonradiation Treatment Response Assessment Version 2024

The American College of Radiology Liver Imaging Reporting and Data System (LI-RADS) standardizes the imaging technique, reporting lexicon, disease categorization, and management for patients with or at risk for hepatocellular carcinoma (HCC). LI-RADS encompasses HCC surveillance with US; HCC diagnosis with CT, MRI, or contrast-enhanced US (CEUS); and treatment response assessment (TRA) with CT or MRI. LI-RADS was recently expanded to include CEUS TRA after nonradiation locoregional therapy or surgical resection. This report provides an overview of LI-RADS CEUS Nonradiation TRA v2024, including a lexicon of imaging findings, techniques, and imaging criteria for posttreatment tumor viability assessment. LI-RADS CEUS Nonradiation TRA v2024 takes into consideration differences in the CEUS appearance of viable tumor and posttreatment changes within and in close proximity to a treated lesion. Due to the high sensitivity of CEUS to vascular flow, posttreatment reactive changes commonly manifest as areas of abnormal perilesional enhancement without washout, especially in the first 3 months after treatment. To improve the accuracy of CEUS for nonradiation TRA, different diagnostic criteria are used to evaluate tumor viability within and outside of the treated lesion margin. Broader criteria for intralesional enhancement increase sensitivity for tumor viability detection. Stricter criteria for perilesional enhancement limit miscategorization of posttreatment reactive changes as viable tumor. Finally, the TRA algorithm reconciles intralesional and perilesional tumor viability assessment and assigns a single LI-RADS treatment response (LR-TR) category: LR-TR nonviable, LR-TR equivocal, or LR-TR viable.

Vertebral metastasis of hepatocellular carcinoma secondary to viral hepatitis B: case report of 2 patients

Bone metastases from liver cancer are rare. We report two cases of bone metastases revealing HBV-induced HCC. A 26-year-old african man presented with 4 months of low back pain in the context of general deterioration. Examination revealed a lumbar spinal syndrome and hepatomegaly. Abdominal ultrasound revealed a multinodular liver, and a CT scan of the spine revealed osteolytic lesions. Biological tests revealed a hepatic cytolysis syndrome, hepatic cholestasis and hepatocellular insufficiency. Alpha foetoprotein levels were elevated and hepatitis B serology was positive. We adopted the diagnosis of HCC of viral B origin with bone metastasis. The second case involved a 44-year-old African man admitted for 10 days with back pain. Examination revealed a spinal syndrome, paraplegia and hepatomegaly. A thoracic-abdominal-pelvic CT scan revealed typical HCC lesions and osteolytic lesions on the ribs, pelvis and vertebrae. The biology revealed a biological inflammatory syndrome, hepatic cytolysis, a hepatocellular insufficiency syndrome and a cholestasis syndrome. Alfa-feto proteins were elevated and HBV serology was positive. The diagnosis of bone metastasis of HCC secondary to HBV infection was accepted.

Simultaneous quantification of Gadoxetic acid and Cisplatin in hepatocellular carcinomas using laser ablation-inductively coupled plasma-mass spectrometry

The gadolinium-based contrast agent Gadoxetic acid and the platinum-based antitumor agent Cisplatin were quantitatively imaged in liver and liver cancer (hepatocellular carcinoma, HCC) tissue of rats by means of laser ablation-inductively coupled plasma-mass spectrometry. HCC bearing rats simultaneously received a tail vein injection of the hepatocyte-specific magnetic resonance imaging contrast agent Gadoxetic acid and a transarterial injection of Cisplatin 15 min before sacrifice and liver removal. Resecting HCC with adjacent liver tissue allows the comparison of Gd, Pt, and endogenous elements like Fe, Cu, and Zn in the various tissue types. Region of interest analysis reveals lower concentrations of Gd in HCC and higher Gd content in the adjacent liver, fitting the selective uptake of Gadoxetic acid into hepatocytes. Furthermore, two malignancy grades and their possible impact on the Gadoxetic acid and Cisplatin uptake are compared. For this, four high grade (G3) and two moderate grade (G2) HCCs were analysed, including a control sample each. Gd concentrations were lower in HCC irrespective of the grade of dedifferentiation (G2, G3) compared to adjacent liver. Despite local arterial Cisplatin injection, concentrations of Pt were similar or also reduced in HCC compared to liver tissue. In addition, endogenous Fe, Cu, and Zn were quantified. While Zn was homogenously distributed, higher Fe concentrations were determined in liver tissue compared to HCC. Hotspots of Cu suggest a deregulated copper homeostasis in certain liver lesions. The Gd and Fe distributions are compared in detail with cellular alterations examined by hematoxylin and eosin staining.

Multimodality imaging of hepatocellular carcinoma and intrahepatic cholangiocarcinoma

Hepatocellular carcinoma and intrahepatic cholangiocarcinoma are the two most common primary malignant tumors of the liver. The similarities and variations in imaging characteristics that may aid in distinguishing between these two primary tumors will be discussed and outlined in this review. Knowledge of imaging techniques that are currently available would assist in the differentiation between these primary malignancies.

Non-invasive preoperative prediction of Edmondson-Steiner grade of hepatocellular carcinoma based on contrast-enhanced ultrasound using ensemble learning

Purpose

This study aimed to explore the clinical value of non-invasive preoperative Edmondson-Steiner grade of hepatocellular carcinoma (HCC) using contrast-enhanced ultrasound (CEUS).

Methods

212 cases of HCCs were retrospectively included, including 83 cases of high-grade HCCs and 129 cases of low-grade HCCs. Three representative CEUS images were selected from the arterial phase, portal vein phase, and delayed phase and stored in a 3-dimensional array. ITK-SNAP was used to segment the tumor lesions manually. The Radiomics method was conducted to extract high-dimensional features on these contrast-enhanced ultrasound images. Then the independent sample T-test and the Least Absolute Shrinkage and Selection Operator (LASSO) were employed to reduce the feature dimensions. The optimized features were modeled by a classifier based on ensemble learning, and the Edmondson Steiner grading was predicted in an independent testing set using this model.

Results

A total of 1338 features were extracted from the 3D images. After the dimension reduction, 10 features were finally selected to establish the model. In the independent testing set, the integrated model performed best, with an AUC of 0.931.

Conclusion

This study proposed an Edmondson-Steiner grading method for HCC with CEUS. The method has good classification performance on independent testing sets, which can provide quantitative analysis support for clinical decision-making.

Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment

Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms.

Evaluation of Multisource Adaptive MRI Fusion for Gross Tumor Volume Delineation of Hepatocellular Carcinoma

Purpose

Tumor delineation plays a critical role in radiotherapy for hepatocellular carcinoma (HCC) patients. The incorporation of MRI might improve the ability to correctly identify tumor boundaries and delineation consistency. In this study, we evaluated a novel Multisource Adaptive MRI Fusion (MAMF) method in HCC patients for tumor delineation.

Methods

Ten patients with HCC were included in this study retrospectively. Contrast-enhanced T1-weighted MRI at portal-venous phase (T1W_PP), contrast-enhanced T1-weighted MRI at 19-min delayed phase (T1W_DP), T2-weighted (T2W), and diffusion-weighted MRI (DWI) were acquired on a 3T MRI scanner and imported to in-house-developed MAMF software to generate synthetic MR fusion images. The original multi-contrast MR image sets were registered to planning CT by deformable image registration (DIR) using MIM. Four observers independently delineated gross tumor volumes (GTVs) on the planning CT, four original MR image sets, and the fused MRI for all patients. Tumor contrast-to-noise ratio (CNR) and Dice similarity coefficient (DSC) of the GTVs between each observer and a reference observer were measured on the six image sets. Inter-observer and inter-patient mean, SD, and coefficient of variation (CV) of the DSC were evaluated.

Results

Fused MRI showed the highest tumor CNR compared to planning CT and original MR sets in the ten patients. The mean ± SD tumor CNR was 0.72 ± 0.73, 3.66 ± 2.96, 4.13 ± 3.98, 4.10 ± 3.17, 5.25 ± 2.44, and 9.82 ± 4.19 for CT, T1W_PP, T2W, DWI, T1W_DP, and fused MRI, respectively. Fused MRI has the minimum inter-observer and inter-patient variations as compared to original MR sets and planning CT sets. GTV delineation inter-observer mean DSC across the ten patients was 0.81 ± 0.09, 0.85 ± 0.08, 0.88 ± 0.04, 0.89 ± 0.08, 0.90 ± 0.04, and 0.95 ± 0.02 for planning CT, T1W_PP, T2W, DWI, T1W_DP, and fused MRI, respectively. The patient mean inter-observer CV of DSC was 3.3%, 3.2%, 1.7%, 2.6%, 1.5%, and 0.9% for planning CT, T1W_PP, T2W, DWI, T1W_DP, and fused MRI, respectively.

Conclusion

The results demonstrated that the fused MRI generated using the MAMF method can enhance tumor CNR and improve inter-observer consistency of GTV delineation in HCC as compared to planning CT and four commonly used MR image sets (T1W_PP, T1W_DP, T2W, and DWI). The MAMF method holds great promise in MRI applications in HCC radiotherapy treatment planning.

NIR-II imaging of hepatocellular carcinoma based on a humanized anti-GPC3 antibody

Liver cancer, of which hepatocellular carcinoma (HCC) is the most common form, is one of the most lethal cancers worldwide. The five-year survival rate for HCC is below 9%, which can be attributed to late diagnosis and limited treatment options at the late stage. Therefore, safe and efficient imaging strategies are urgently needed to facilitate HCC diagnosis and stage evaluation. The development of the second near infrared window (NIR-II, 1000-1700 nm) fluorescence imaging offers the advantages of enhanced resolutions, deeper penetration depth, and less autofluorescence compared to traditional NIR-I window (700-900 nm) imaging. Herein, an HCC targeted NIR-II fluorescent probe, GPC-ICG, was developed by labelling a humanized anti-GPC3 monoclonal antibody with indocyanine green (ICG). Compared to the negative control IgG-ICG probe, the GPC3-ICG probe demonstrated specific GPC3 targeting capability in vitro. And for GPC3 positive Huh-7 tumor bearing mice, the GPC3-ICG probe specifically accumulated in subcutaneous xenografts, with a tumor-background ratio (TBR) of up to 3. The NIR-II imaging of mice organs ex vivo also indicated that GPC3-ICG specifically targeted Huh-7 tumor tissue. Overall, GPC3-ICG is a promising NIR-II probe for GPC3 targeted imaging of HCC.

Meta-analysis and systematic review of contrast-enhanced ultrasound in evaluating the treatment response after locoregional therapy of hepatocellular carcinoma

PURPOSE

Contrast-enhanced ultrasound (CEUS) is a useful tool to assess treatment response after percutaneous ablation or transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). Here, we performed a systematic review and meta-analysis to evaluate the usefulness of CEUS in identifying residual tumor after locoregional therapy.

METHODS

PubMed, Scopus, and Cochrane library databases were searched from their inception until March 8, 2021, for diagnostic test accuracy studies comparing CEUS to a reference standard for identifying residual tumors after locoregional therapy of HCC. The pooled sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) were obtained using a bivariate random effects model. Subgroup analyses were performed by stratifying the studies based on study design, type of locoregional therapy, CEUS criteria for residual tumor, timing of CEUS follow up, and type of standard reference.

RESULTS

Two reviewers independently evaluated 1479 publications. After full-text review, 142 studies were found to be relevant, and 43 publications (50 cohorts) were finally included. The overall sensitivity of CEUS in detection of residual disease estimated from the bivariate random effects model was 0.85 (95% CI 0.80-0.89). Similarly, the overall specificity was 0.94 (95% CI 0.91-0.96). The diagnostic accuracy was 93.5%. The DOR was 70.1 (95% CI 62.2-148), and the AUROC was 0.95. Importantly, subgroup analysis showed no apparent differences in the diagnostic performance between locoregional therapy (TACE vs. ablation) and criteria used to define residual enhancement, timing of performing CEUS, study design, or type of reference standard.

CONCLUSION

CEUS is a highly accurate method to identify HCC residual tumor after TACE or percutaneous ablation.

Preoperative prediction of pathological grading of hepatocellular carcinoma using machine learning-based ultrasomics: A multicenter study

PURPOSE

The present study investigated the value of ultrasomics signatures in the preoperative prediction of the pathological grading of hepatocellular carcinoma (HCC) via machine learning.

METHODS

A total of 193 patients were collected from three hospitals. The patients from two hospitals (n = 160) were randomly divided into training set (n = 128) and test set (n = 32) at a 8:2 ratio. The patients from a third hospital were used as an independent validation set (n = 33). The ultrasomics features were extracted from the tumor lesions on the ultrasound images. Support vector machine (SVM) was used to construct three preoperative pathological grading models for HCC on each dataset. The performance of the three models was evaluated by area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and accuracy.

RESULTS

The ultrasomics signatures extracted from the grayscale ultrasound images could successfully differentiate between high- and low-grade HCC lesions on the training set, test set, and the independent validation set (p < 0.05). On the test set and the validation set, the combined model's performance was the highest, followed by the ultrasomics model and the clinical model successively (p < 0.05). Their AUC (along with 95 %CI) of these models was 0.874(0.709-0.964), 0.789(0.608-0.912), 0.720(0.534-0.863) and 0.849(0.682-0.949), 0.825(0.654-0.935), 0.770(0.591-0.898), respectively.

CONCLUSION

Machine learning-based ultrasomics signatures could be used for noninvasive preoperative prediction of pathological grading of HCC. The combined model displayed a better predictive performance for pathological grading of HCC and had a stronger generalization ability.

Contrast-enhanced ultrasound (CEUS) in HCC diagnosis and assessment of tumor response to locoregional therapies

Hepatocellular carcinoma (HCC) is a global problem constituting the second leading cause of cancer deaths worldwide, thereby necessitating an accurate and cost-effective solution for managing care. Ultrasound is well poised to address this need due to its low cost, portability, safety, and excellent temporal resolution. The role of ultrasound for HCC screening has been well established and supported by multiple international guidelines. Similarly, contrast-enhanced ultrasound (CEUS) can be used for the characterization of focal liver lesions in high-risk populations, and standardized criteria for CEUS have been established by the American College of Radiology Liver Imaging Reporting & Data System (LI-RADS). Following HCC identification, CEUS can also be highly beneficial in treatment planning, delivery, and monitoring HCC response to locoregional therapies. Specific advantages of CEUS include providing real-time treatment guidance and improved diagnostic performance for the detection of residual tumor viability or recurrence, thereby identifying patients in need of retreatment substantially earlier than contrast-enhanced CT and MRI. This review provides a primer on ultrasound and CEUS for the screening and characterization of HCC, with an emphasis on assessing tumor response to locoregional therapies.

Is the Concurrent Use of Sorafenib and External Radiotherapy Feasible for Advanced Hepatocellular Carcinoma? A Meta-Analysis

We evaluate the feasibility of a concurrent application of sorafenib and external beam radiation therapy (EBRT) for advanced hepatocellular carcinoma (HCC). PubMed, Embase, Medline, and Cochrane Library were searched up to 9 April 2021. The primary endpoint was grade ≥3 complications, and the secondary endpoint was overall survival (OS). Subgroup analyses were performed for studies with the EBRT targets, intrahepatic vs. non-intrahepatic lesions (e.g., extrahepatic metastases or malignant vessel involvement only). Eleven studies involving 512 patients were included in this meta-analysis. Pooled rates of gastrointestinal, hepatologic, hematologic, and dermatologic grade ≥3 toxicities were 8.1% (95% confidence interval (CI): 4.8-13.5, I2 = ~0%), 12.9% (95% CI: 7.1-22.1, I2 = 22.4%), 9.1% (95% CI: 3.8-20.3, I2 = 51.3%), and 6.8% (95% CI: 3.8-11.7, I2 = ~0%), respectively. Pooled grade ≥3 hepatologic and hematologic toxicity rates were lower in studies targeting non-intrahepatic lesions than those targeting intrahepatic lesions (hepatologic: 3.3% vs. 17.1%, p = 0.041; hematologic: 3.3% vs. 16.0%, p = 0.078). Gastrointestinal and dermatologic grade ≥3 complications were not significantly different between the subgroups. Regarding OS, concurrent treatment was more beneficial than non-concurrent treatment (odds ratio: 3.3, 95% CI: 1.3-8.59, p = 0.015). One study reported a case of lethal toxicity due to tumor rupture and gastrointestinal bleeding. Concurrent treatment can be considered and applied to target metastatic lesions or local vessel involvement. Intrahepatic lesions should be treated cautiously by considering the target size and hepatic reserve.

Major and ancillary features according to LI-RADS in the assessment of combined hepatocellular-cholangiocarcinoma

Background

The aim of the study was to investigate the performance of the Liver Imaging Reporting and Data System (LI-RADS) v2018 for combined hepatocellular-cholangiocarcinoma (cHCC-CCA) identifying the features that allow an accurate characterization.

Patients and methods

Sixty-two patients (median age, 63 years; range, 38–80 years), with pre-surgical biopsy diagnosis of hepatocellular carcinoma (HCC) that underwent hepatic resection, comprised our retrospective study. All patients were subject to multidetector computed tomography (MDCT); 23 patients underwent to magnetic resonance (MR) study. The radiologist reported the presence of the HCC by using LIRADS v2018 assessing major and ancillary features.

Results

Final histological diagnosis was HCC for 51 patients and cHCC-CCA for 11 patients. The median nodule size was 46.0 mm (range 10–190 mm). For cHCC-CCA the median size was 33.5 mm (range 20–80 mm), for true HCC the median size was 47.5 mm (range 10–190 mm). According to LIRADS categories: 54 (87.1%) nodules as defined as LR-5, 1 (1.6%) as LR-3, and 7 (11.3%) as LR-M. Thirty-nine nodules (63%) showed hyper-enhancement in arterial phase; among them 4 were cHCC-CCA (36.4% of cHCC-CCA) and 35 (68.6%) true HCC. Forty-three nodules (69.3%) showed washout appearance; 6 cHCC-CCAs (54.5% of cHCC-CCA) and 37 true HCC (72.5%) had this feature. Only two cHCC-CCA patients (18.2% of cHCC-CCA) showed capsule appearance. Five cHCC-CCA (71.4% of cHCC-CCA) showed hyperintensity on T2-W sequences while two (28.6%) showed inhomogeneous signal in T2-W. All cHCC-CCA showed restricted diffusion. Seven cHCC-CCA patients showed a progressive contrast enhancement and satellite nodules.

Conclusions

The presence of satellite nodules, hyperintense signal on T2-W, restricted diffusion, the absence of capsule appearance in nodule that shows peripheral and progressive contrast enhancement are suggestive features of cHCC-CCA.

Targeted and Multifunctional Technology for Identification between Hepatocellular Carcinoma and Liver Cirrhosis

Continuously updated diagnostic methods and advanced imaging methods have led to an increase in the early detection rate of small liver cancer; however, even with current diagnosis methods, it is still challenging to accurately judge a nodule with a diameter less than 2 cm whether it is hepatocellular carcinoma or liver cirrhosis. To solve this issue, a new technology is needed to distinguish above two kinds of liver nodules. There is an emerging imaging method that improves tissue resolution and sensitivity to detect micronodules with diameters less than 2 cm. To detect micronodules, photoacoustic imaging was used to provide noninvasive images at depths of several centimeters with a resolution of approximately 100 μm. To improve specificity, we developed a probe that specifically targets hepatocellular carcinoma by recognizing the biomarker GPC3 on the hepatocellular carcinoma cell membrane. The probe not only has a strong photoacoustic signal but also has a magnetic resonance signal. Furthermore, the material owns photothermal effect that absorbs longer wavelength light and releases heat that effectively and accurately kills tumor cells, thus improving patient's survival and postoperative quality of life. Herein, we present a new technology that uses photoacoustic imaging to image and target microhepatocellular carcinoma biological processes derived from liver cirrhosis with high spatial resolution.

State of the art in magnetic resonance imaging of hepatocellular carcinoma

Background

Liver cancer is the sixth most common cancer worldwide and the second leading cause of cancer mortality. Chronic liver disease caused by viral infection, alcohol abuse, or other factors can lead to cirrhosis. Cirrhosis is the most important clinical risk factor for hepatocellular carcinoma (HCC) whereby the normal hepatic architecture is replaced by fibrous septa and a spectrum of nodules ranging from benign regenerative nodules to HCC, each one of them with different imaging features.

Conclusions

Furthermore, advanced techniques including the quantification of hepatic and intralesional fat and iron, magnetic resonance elastography, radiomics, radiogenomics, and positron emission tomography (PET)-MRI are highly promising for the extraction of new imaging biomarkers that reflect the tumor microenvironment and, in the future, may add decision-making value in the management of patients with HCC.

The Diagnostic Role of SPINK1 in Differentiating Hepatocellular Carcinoma From Nonmalignant Lesions

BACKGROUND AND AIM

Distinction of small-sized hepatocellular carcinoma (HCC) from dysplastic nodules may be difficult. In addition, distinction of well-differentiated HCC (WD-HCC) from high-grade dysplastic nodule (HGDN) is also difficult in small needle biopsy. We aimed to study serine peptidase inhibitor, Kazal type 1 (SPINK1) immunohistochemical expression in HCC to differentiate it from nonmalignant lesions.

METHODS

This study included 179 specimens from the archival material of Pathology Department, National Liver Institute, Menoufia University, between 2007 and 2014, divided as 93 HCC and 86 nonmalignant lesions. All cases were stained for SPINK1 antibody.

RESULTS

SPINK1 was expressed in 76.3% of HCC cases with a diagnostic accuracy of 79.3%.There was a significant difference between focal nodular hyperplasia and WD-HCC cases regarding mean value of SPINK1 expression (P=0.015). In addition, there was low SPINK1 score in cirrhosis cases compared with WD-HCC. Moreover, there was a high significant difference between WD-HCC and HGDN regarding SPINK1 expression (P=0.001), with 83.3% sensitivity and 84.6% specificity.

CONCLUSIONS

SPINK1 can be used to differentiate between a WD-HCC and a HGDN with high diagnostic validity.

Predicting the grade of hepatocellular carcinoma based on non-contrast-enhanced MRI radiomics signature

PURPOSE

This study was conducted in order to investigate the value of magnetic resonance imaging (MRI)-based radiomics signatures for the preoperative prediction of hepatocellular carcinoma (HCC) grade.

METHODS

Data from 170 patients confirmed to have HCC by surgical pathology were divided into a training group (n = 125) and a test group (n = 45). The radiomics features of tumours based on both T1-weighted imaging (WI) and T2WI were extracted by using Matrix Laboratory (MATLAB), and radiomics signatures were generated using the least absolute shrinkage and selection operator (LASSO) logistic regression model. The predicted values of pathological HCC grades using radiomics signatures, clinical factors (including age, sex, tumour size, alpha fetoprotein (AFP) level, history of hepatitis B, hepatocirrhosis, portal vein tumour thrombosis, portal hypertension and pseudocapsule) and the combined models were assessed.

RESULTS

Radiomics signatures could successfully categorise high-grade and low-grade HCC cases (p < 0.05) in both the training and test datasets. Regarding the performances of clinical factors, radiomics signatures and the combined clinical and radiomics signature (from the combined T1WI and T2WI images) models for HCC grading prediction, the areas under the curve (AUCs) were 0.600, 0.742 and 0.800 in the test datasets, respectively. Both the AFP level and radiomics signature were independent predictors of HCC grade (p < 0.05).

CONCLUSIONS

Radiomics signatures may be important for discriminating high-grade and low-grade HCC cases. The combination of the radiomics signatures with clinical factors may be helpful for the preoperative prediction of HCC grade.

KEY POINTS

• The radiomics signature based on non-contrast-enhanced MR images was significantly associated with the pathological grade of HCC. • The radiomics signatures based on T1WI or T2WI images performed similarly at predicting the pathological grade of HCC. • Combining the radiomics signature and clinical factors (including age, sex, tumour size, AFP level, history of hepatitis B, hepatocirrhosis, portal vein tumour thrombosis, portal hypertension and pseudocapsule) may be helpful for the preoperative prediction of HCC grade.

PET/MRI for Gastrointestinal Imaging: Current Clinical Status and Future Prospects

Positron emission tomography (PET)/computed tomography (CT) with 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment for numerous gastrointestinal malignancies. However, it is often supplemented by magnetic resonance imaging (MRI) for local tumor staging. Hybrid PET/MRI scanners, which acquire PET data and MRI data simultaneously, have the potential to provide accurate whole-body staging in a single examination. Furthermore, to address certain limitations of FDG, many new PET tracers have been developed to probe distinctive aspects of tumor biology.

Hepatocellular Carcinoma: In Vivo Evaluation of Water Percentage as a Prognostic Biomarker Using Magnetic Resonance Imaging 3D-VIBE Multiecho Dixon

INTRODUCTION

It is urgent to find an effective method to diagnose and prognose early hepatocellular carcinoma (HCC). The purpose of this study was to investigate the correlation between HCC histological degree and water percentage (WP) obtained from magnetic resonance imaging 3D-VIBE multiecho Dixon, and to evaluate the feasibility of WP in the postoperative prediction of early HCC recurrence.

METHODS AND MATERIALS

From June 2016 to July 2017, 76 patients with diagnostic HCC all underwent 3D-VIBE Multiecho Dixon and ultrahigh b value diffusion-weighted imaging (DWI) examination. Freehand regions of interests were placed to measure the WP and apparent diffusion coefficient (ADC) value. The Edmondson-Steiner (E-S) grades proved by histopathological results were acquired from all patients. Comparisons between mean WP and ADC with E-S grades I-IV were performed using Kruskal-Wallis test and one-way ANOVA. Least Significant Difference t-test (LSD-t test) was applied to compare particular pairs of mean ADC value between every two E-S groups. Correlations between WP, ADC, and E-S grades were assessed by Spearman's rank correlation test. The Mann-Whitney U test was utilized to compare the difference of mean WP between recurrence and nonrecurrence group. The receiver operating characteristic (ROC) curves were calculated to estimate the diagnostic effect of 3D-VIBE Multiecho Dixon and ultrahigh b value DWI to HCC. Kaplan-Meier method was used to evaluate the recurrence free survival (RFS) after surgical resection.

RESULTS

Mean WP values among groups E-S I to IV were 91.8%, 95.2%, 96.4%, and 97.7%, respectively. A positive correlation was exhibited between the WP and histopathological E-S grades (r = 0.480, p < 0.01). The ADC values based on E-S grades were 0.93, 0.82, 0.74, and 0.62 × 10^-3 mm²/s, respectively. Significant differences were found between every two E-S groups (p < 0.01), and a negative correlation between ADC and E-S grades (r = -0.784, p = 0.000) was observed. Mean value of WP was 97.2% in recurrence group and 94.6% in nonrecurrence group (p < 0.01). The optimal cutoff value was 95.7%. The maximal area under the ROC curve was 0.747 ± 0.06 for WP, 0.631 ± 0.07 for ADC, and 0.753 ± 0.06 for the combination of WP and ADC. Mean RFS was 18.1 months in the lower WP and 10.7 months in higher WP group (p < 0.01).

CONCLUSIONS

WP can be used as a potential biomarker for the diagnosis and prognosis of HCC. A lower value of WP may imply a better outcome in patients after surgical resection.

2017 Version of LI-RADS for CT and MR Imaging: An Update

The Liver Imaging Reporting and Data System (LI-RADS) is a reporting system created for the standardized interpretation of liver imaging findings in patients who are at risk for hepatocellular carcinoma (HCC). This system was developed with the cooperative and ongoing efforts of an American College of Radiology-supported committee of diagnostic radiologists with expertise in liver imaging and valuable input from hepatobiliary surgeons, hepatologists, hepatopathologists, and interventional radiologists. In this article, the 2017 version of LI-RADS for computed tomography and magnetic resonance imaging is reviewed. Specific topics include the appropriate population for application of LI-RADS; technical recommendations for image optimization, including definitions of dynamic enhancement phases; diagnostic and treatment response categories; definitions of major and ancillary imaging features; criteria for distinguishing definite HCC from a malignancy that might be non-HCC; management options following LI-RADS categorization; and reporting. ^©RSNA, 2017.

Accuracy of the diagnostic evaluation of hepatocellular carcinoma with LI-RADS

Background There are few studies about the Liver Imaging Reporting and Data System (LI-RADS), which was developed with the purpose of standardizing the interpretation and reporting of liver imaging examinations in patients at risk for hepatocellular carcinoma (HCC). Purpose To evaluate the diagnostic accuracy of HCC diagnosis using LI-RADS. Material and Methods The computed tomography (CT), magnetic resonance imaging (MRI), and clinical data of 297 lesions in 249 patients between June 2012 and August 2013 were retrospectively analyzed. Using LI-RADS 2014, two radiologists evaluated the lesions and a LI-RADS category was retrospectively assigned to each nodule. Results The final diagnoses of 297 nodules in 249 patients consisted of 191 malignant and 106 benign lesions. Out of 44 LI-RADS category 1 lesions, none were HCCs. However, 2/25 category 2 lesions, 3/35 category 3 lesions, 16/25 category 4 lesions, 151/156 category 5 lesions, and 3/12 category LRM/OM (probable malignancy, not specific for HCC/other malignancy) lesions were HCCs. The Kappa value was 0.44 (95% confidence interval [CI] = 0.39-0.49) between two observers during LI-RADS grading. Conclusion The negative predictive value of LI-RADS category 1 was 100%. In addition, a relevant proportion of lesions categorized as category 2 or 3, or even as other malignancies, were HCCs. LI-RADS category 5 had a high specificity for HCC. LI-RADS was not able to give a differential diagnosis for the false-positive lesions of LI-RADS category 5.

Material density iodine images in dual-energy CT: Detection and characterization of hypervascular liver lesions compared to magnetic resonance imaging

PURPOSE

To determine the diagnostic potential of Material Density (MD) iodine images in dual-energy CT (DECT) for the detection and characterization of hypervascular liver lesions compared to monenergetic 65keV images, using MRI as the standard.

MATERIALS AND METHODS

The study complied with HIPAA guidelines and was approved by the institutional review board. Fifty-two patients (36 men, 16 women; age range, 29-87 years) with 236 hypervascular liver lesions (benign, n=31; malignant, n=205; mean diameter, 29.4mm; range: 6-90.6mm) were included. All of them underwent both contrast-enhanced single-source DECT and contrast-enhanced abdominal MRI within three months. Late arterial phase CT imaging was performed with dual energies of 140 and 80kVp. Protocol A showed monoenergetic 65keV images, and protocol B presented MD-iodine images. Three radiologists qualitatively evaluated randomized images, and lesion detection, characterization, and reader confidence were recorded. Liver-to-lesion ratio (LLR) and contrast-to-noise ratio (CNR) were assessed on protocol A, protocol B, and MRI. Paired t-tests were used to compare LLR, CNR, and the number of detected lesions.

RESULTS

LLR was significantly increased in protocol B (2.8±2.33) compared to protocol A (0.77±0.55) and MRI (0.61±0.66). CNR was significantly higher in protocol B (0.08±0.04) compared to protocol A (0.01±0.01) and MRI (0.01±0.01). All three observers correctly identified more liver lesions using protocol B vs protocol A: 83.13% vs 63.64%, 84.57% vs 68.09%, and 79.37% vs 65.52%. There was no significant difference between the three observers in classification of a lesion as benign or malignant. However, higher diagnostic confidence was reported more frequently by the experienced radiologist when using protocol B vs protocol A (84.6% vs 75%).

CONCLUSION

MD-iodine images in DECT help to increase the conspicuity and detection of hypervascular liver lesions.

Liver Imaging Reporting and Data System: an expert consensus statement

The increasing incidence and high morbidity and mortality of hepatocellular carcinoma (HCC) have inspired the creation of the Liver Imaging Reporting and Data System (LI-RADS). LI-RADS aims to reduce variability in exam interpretation, improve communication, facilitate clinical therapeutic decisions, reduce omission of pertinent information, and facilitate the monitoring of outcomes. LI-RADS is a dynamic process, which is updated frequently. In this article, we describe the LI-RADS 2014 version (v2014), which marks the second update since the initial version in 2011.

Radiofrequency ablation for HCC patients with multifocal tumours meeting the Milan criteria: A single-centre experience

BACKGROUND

Radiofrequency ablation (RFA) has been recommended as a curative treatment for patients with single early-stage unifocal hepatocellular carcinomas (HCCs) for years; however, the effect of this treatment on multifocal tumours has remained uncertain.

AIMS

We conducted a retrospective study to evaluate the overall survival (OS) and recurrence-free survival (RFS) rates of early HCC patients with multiple tumours subjected to different RFA modalities.

METHODS

One hundred fifty-four HCC patients with multifocal tumours who met the Milan criteria and underwent RFA were enrolled in this study. We divided the patients into 3 groups according to the surgical approach utilised (percutaneous, laparoscopic and open RFA; selection was based on the locations of the tumours for whether they were adhered to the subhepatic inferior vena cava or the gastrointestinal tract) and into 2 subgroups according to the tumour numbers and locations.

RESULTS

No deaths occurred in the 30-day post-operation period, and there were no significant differences in the complication, OS or RFS rates between the 3 groups. The 1-, 3- and 5-year OS rates were 88.9%, 75.5% and 50.9% in the subgroup with 2 tumours, respectively, versus 91.3%, 56.3% and 17.5% in the subgroup with 3 tumours, respectively (P=0.001). The corresponding values were 93.2%, 77.4% and 50.8% in the subgroup with tumours in the same segment and 82.4%, 54.8% and 23.0% in the subgroup with tumours in different segments (P=0.001).

CONCLUSION

RFA was proven to be an effective and safe method for the treatment of multifocal HCCs. Among the patients with 2 tumours within the same segment, RFA achieved better long-term outcomes in terms of both overall and recurrence-free survival.

Malignancy characterization of hepatocellular carcinomas based on texture analysis of contrast-enhanced MR images

PURPOSE

To investigate the performance of texture analysis in characterizing malignancy of hepatocellular carcinomas (HCCs) based on contrast-enhanced magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Gd-DTPA contrast-enhanced MRI data of 46 consecutive subjects with resected HCC were retrieved. The mean intensity and gray-level run-length nonuniformity (GLN) were quantified as the discriminative features based on the arterial phase images and compared between groups with different histological grading using independent Student's t-test or Welch-Satterthwaite approximate t-test for data following a normal distribution and Mann-Whitney U-test for data violating the normal distribution. The performance of texture features in differentiating the biological aggressiveness of HCC was assessed using receiver operating characteristic (ROC) analysis. P < 0.05 was set as the significance level.

RESULTS

Low-grade HCCs had increased mean intensity and decreased GLN in four directions, as compared with high-grade HCCs (P < 0.0005). A cutoff value of 739.37 for the average intensity resulted in an optimal sensitivity of 76% and specificity of 100% for histological grading discrimination. Cutoff values of 34.18, 66.59, 36.82, and 80.31 for the GLN in four directions (0°, 45°, 90°, 135°) resulted in an optimal sensitivity of 92%, 84%, 68%, 76% and specificity 66.70%, 71.40%, 85.70%, 76.20%, respectively. The areas under the ROC curve for the average intensity and GLN in four directions were 0.918, 0.846, 0.836, 0.827, and 0.838, respectively.

CONCLUSION

Texture features indexed by mean and GLN based on the arterial phase images reflect biologic aggressiveness, and may have potential applications in predicting the histological grading of HCC preoperatively. Evidence level: 4 J. MAGN. RESON. IMAGING 2017;45:1476-1484.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging With Gadolinium Ethoxybenzyl Diethylenetriamine Pentaacetic Acid for Quantitative Assessment of Vascular Effects on Hepatocellular-Carcinoma Lesions Treated by Transarterial Chemoembolization or Radiofrequency Ablation

PURPOSE

The aim of this study was to investigate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in evaluation of blood flow changes related to transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) procedures in patients with hepatocellular carcinoma (HCC) lesions.

METHODS

Fifty-four patients, with biopsy-proven HCC, who underwent TACE or RFA, were evaluated, 1 month after treatment, with upper abdominal MRI examination. Multiplanar T2-weighted, T1-weighted, and dynamic contrast-enhanced sequences were acquired. Dedicated perfusion software (T1 Perfusion Package, Viewforum; Philips Medical Systems, The Netherlands) was used to generate color permeability maps. After placing regions of interest in normal hepatic parenchyma, in successfully treated lesions, and in area of recurrence, the following perfusion parameters were calculated and statistically analyzed: relative arterial, venous, and late enhancement; maximum enhancement; maximum relative enhancement, and time to peak.

RESULTS

Twenty-one of 54 patients had residual disease, and perfusion parameters values measured within tumor tissue were: relative arterial enhancement median, 42%; relative venous enhancement median, 69%; relative late enhancement median, 57.7%; maximum enhancement median, 749.6%; maximum relative enhancement median, 69%; time to peak median, 81.1 seconds. As for all the evaluated parameters, a significant difference (P < 0.05) was found between residual viable tumor tissue and effective treated lesions.

CONCLUSIONS

Dynamic contrast-enhanced MRI represents a complementary noninvasive tool that may offer quantitative and qualitative information about HCC lesions treated with TACE and RFA.

Intraobserver and Interobserver Agreement in the Evaluation of Tumor Vascularization With Computed Tomography Perfusion in Cirrhotic Patients With Hepatocellular Carcinoma

OBJECTIVES

To evaluate intrareader and inter-reader agreement in CT perfusion (Perf) measurements in cirrhotic patients with hepatocellular carcinoma (HCC) lesions.

METHODS

Sixteen patients with HCC (9 untreated, 5 recurrence/residual disease after transarterial chemoembolization, and 2 after radiofrequency ablation treatment) underwent standard CT examination and a Perf study; a quantitative map of arterial and portal Perf by means of a color scale was generated. With dedicated Perf software, the following parameters were calculated on untreated and treated HCC lesions and on cirrhotic parenchyma: hepatic Perf, tissue blood volume, hepatic perfusion index, arterial perfusion, and time to peak. Intraobserver and interobserver agreements were assessed for 2 readers with Bland-Altman plots, intraclass correlation coefficients (ICCs), coefficients of variation, and repeatability.

RESULTS

In HCC lesions, agreement analysis demonstrated higher intra-agreement values in comparison with interagreement (range of ICC values, 0.26-0.59 between readers and 0.67-0.94 between readings). Lower interagreement was found for treated HCC lesions in comparison with untreated lesions (range of ICC values, respectively, 0.12-0.54 and 0.31-0.89).

CONCLUSIONS

For all Perf parameters intra-agreement was higher than interagreement, even though a relatively wide range of 95% limits of agreement was found in both cases.

Recent advances in the imaging of hepatocellular carcinoma

The role of imaging is crucial for the surveillance, diagnosis, staging and treatment monitoring of hepatocellular carcinoma (HCC). Over the past few years, considerable technical advances were made in imaging of HCCs. New imaging technology, however, has introduced new challenges in our clinical practice. In this article, the current status of clinical imaging techniques for HCC is addressed. The diagnostic performance of imaging techniques in the context of recent clinical guidelines is also presented.

Navigated three-dimensional T1-weighted gradient-echo sequence for gadoxetic acid liver magnetic resonance imaging in patients with limited breath-holding capacity

PURPOSE

To determine whether a navigator-gated three-dimensional T1-weighted gradient-echo sequence (T1W-GRE, navigated LAVA) can improve diagnostic performance for the detection of focal liver lesions (FLLs) compared to standard breath-hold (BH) T1W-GRE breath-hold LAVA (BH-LAVA) during the hepatobiliary phase (HBP) of gadoxetic acid liver magnetic resonance imaging (MRI) in patients with limited breath-holding capacity.

MATERIALS AND METHODS

This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. We included 372 patients who underwent liver MRI including both navigated LAVA and BH-LAVA sequences. Overall image quality of the two HBP image sets was compared. In patients with limited breath-holding capacity, diagnostic performances in detecting FLLs on the two HBP images were compared using jackknife-alternative free-response receiver-operating characteristic (JAFROC) analysis by two reviewers.

RESULTS

There were 13 cases (13/372; 3.5%) of image acquisition failure using the navigated LAVA sequence due to severe irregular breathing, and 50 of 359 patients had limited breath-holding capacity. In these patients, overall image quality of navigated LAVA (2.78 ± 0.95) was significantly better than that of BH-LAVA (2.42 ± 0.81, P < 0.005), and both readers showed significantly higher JAFROC figure-of-merit values with navigated LAVA compared to BH-LAVA (0.94 and 0.86 in reviewer 1, respectively; 0.89 and 0.83 in reviewer 2, respectively, P < 0.005). Overall image quality of navigated LAVA was also better than that of BH-LAVA in patients with sufficient breath-holding capacity (n = 309, 3.96 ± 0.88, 3.81 ± 0.66, respectively, P < 0.001).

CONCLUSION

The navigated LAVA sequence could provide better image quality and diagnostic performance in detecting FLLs than BH-LAVA in patients with limited breath-holding capacity during HBP of gadoxetic acid MRI.

Irreversible electroporation of hepatocellular carcinoma: preliminary report on the diagnostic accuracy of magnetic resonance, computer tomography, and contrast-enhanced ultrasound in evaluation of the ablated area

OBJECTIVE

Irreversible electroporation (IRE) is a new ablation modality. Our purpose was to describe the effectiveness and the safety of the treatment and to evaluate the magnetic resonance imaging (MRI), computed tomography (CT) and contrast-enhanced ultrasound (CEUS) diagnostic accuracy in HCC patients treated with IRE at 1-, 3-, and 6-month follow-up.

MATERIALS AND METHODS

In an 18-month period, we treated 24 HCC lesions in 20 patients unfit for surgery. MRI, CT and CEUS were performed before and one, 3 and 6 month after IRE. We employed the liver-specific contrast medium Primovist (gadolinium ethoxybenzyl dimeglumine) in MRI. After IRE the lesions were classified as responders or non-responders to the treatment according to the mRECIST and the complications were recorded. We evaluated the size, shape, signal intensity (T1-W, T2-W, and DWI) in MRI, dynamic contrast enhancement pattern for CEUS, CT and MRI and signal behavior during the liver-specific phase for MRI.

RESULTS

According to mRECIST, at 1 month MRI and CEUS showed a complete response (CR) in 91.7% of cases (22/24) tumors, while there was partial response (PR) in the remaining 2/24 (8.3%) treated nodules; in CT study all ablated zone appeared as necrotic (CR 100%). The residual viable tumor in MRI and in CEUS study had similar diameter (10 mm). No new HCC were identified from MRI, CT or CEUS. At 3 months MRI and CEUS showed the same results seen after 1 month from the treatment. Twenty-two necrotic lesions, and 2 residual tumors were found (CR = 91.7% and PD = 8.3%). In MRI study the two cases of residual tumor tissue had a diameter of 11 and 12 mm each. At CEUS the diameter of residual HCC was similar to the diameter at 1 month. CT showed 23 necrotic areas and one residual viable tissue in the treated zone, with a diameter of 10 mm (CR = 95.3% and PD = 4.7%). No new foci of HCC were identified from all imaging studies. At 6 months MRI, CEUS, and CT showed 22 necrotic lesions and 2 residual tumors in ablated zone (CR = 91.7% and PD = 8.3%). At MRI the diameters of the two residual viable HCCs were 12 and 14 mm, at CEUS the diameters were 11 and 12 mm, while at CT the diameters were 10 and 10 mm. No statistical difference was evaluated between CR, PR, PD percentage values for MRI, CT and CEUS (p value > 0.05 at Chi-square test). No major vascular complication was recorded after IRE. Six out of 20 patients (30%) showed a transient hepatic intensity difference (THID) area within the normal liver parenchyma adjacent to the treated lesions. Two of the 20 patients (10%) showed an absent concentration of liver-specific contrast medium around the ablation zone. Two patients developed complications, consisting in a peripheral arteriovenous shunt and a segmental dilation of the intrahepatic biliary ducts. We found no statistically significant difference in morphology, size (variation in the largest diameter), signal intensity in T1-weighted images, in T2-weighted images, in DWI and in the related map of the apparent diffusion coefficient (ADC), presence or absence of contrast enhanced during the arterial, portal, and late phase in MRI, CT, and CEUS, and signal characteristic during the liver-specific phase in MRI of the ablation zone at 1, 3, and 6 months.

CONCLUSION

IRE is a feasible, safe and efficient modality in the treatment of patients with non-resectable HCC. We had no major complication, even when the ablated lesion was adjacent to major branches of the portal vein. All images techniques showed similar accuracy during the follow-up at 1, 3, and 6 months in the assessment ablated zone.

Focal liver lesions: Practical magnetic resonance imaging approach

With the widespread of cross-sectional imaging, a growth of incidentally detected focal liver lesions (FLL) has been observed. A reliable detection and characterization of FLL is critical for optimal patient management. Maximizing accuracy of imaging in the context of FLL is paramount in avoiding unnecessary biopsies, which may result in post-procedural complications. A tremendous development of new imaging techniques has taken place during these last years. Nowadays, Magnetic resonance imaging (MRI) plays a key role in management of liver lesions, using a radiation-free technique and a safe contrast agent profile. MRI plays a key role in the non-invasive correct characterization of FLL. MRI is capable of providing comprehensive and highly accurate diagnostic information, with the additional advantage of lack of harmful ionizing radiation. These properties make MRI the mainstay for the noninvasive evaluation of focal liver lesions. In this paper we review the state-of-the-art MRI liver protocol, briefly discussing different sequence types, the unique characteristics of imaging non-cooperative patients and discuss the role of hepatocyte-specific contrast agents. A review of the imaging features of the most common benign and malignant FLL is presented, supplemented by a schematic representation of a simplistic practical approach on MRI.

MRI of hepatocellular carcinoma: an update of current practices

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and liver transplantation is the optimal treatment for selected patients with HCC and chronic liver disease (CLD). Accurate selection of patients for transplantation is essential to maximize patient outcomes and ensure optimized allocation of donor organs. Magnetic resonance imaging (MRI) is a powerful tool for the detection, characterization, and staging of HCC. In patients with CLD, the MRI findings of an arterial-enhancing mass with subsequent washout and enhancing capsule on delayed interstitial phase images are diagnostic for HCC. Major organizations with oversight for organ donor distribution, such as The Organ Procurement and Transplantation Network (OPTN), accept an imaging diagnosis of HCC, no longer requiring tissue biopsy. In patients that are awaiting transplantation, or are not candidates for liver transplantation, localized therapies such as transarterial chemoembolization and radiofrequency ablation may be offered. MRI can be used to monitor treatment response. The purpose of this review article is to describe the role of imaging methods in the diagnosis, staging, and follow-up of HCC, with particular emphasis on established and evolving MRI techniques employing nonspecific gadolinium chelates, hepatobiliary contrast agents, and diffusion weighted imaging. We also briefly review the recently developed Liver Imaging Reporting and Data System (LI-RADS) formulating a standardized terminology and reporting structure for evaluation of lesions detected in patients with CLD.

Hepatocellular Carcinoma: Review of Epidemiology, Screening, Imaging Diagnosis, Response Assessment, and Treatment

Hepatocellular carcinoma is a common malignancy for which prevention, screening, diagnosis, treatment, and surveillance demand a multidisciplinary approach. Knowledge of the underlying pathophysiology as well as advances in clinical management should be employed by radiologists to effectively communicate with hepatologists, surgeons, and oncologists. In this review article, we present recent developments in the clinical management of hepatocellular carcinoma.

Magnetic resonance imaging of the cirrhotic liver: An update

Noninvasive imaging has become the standard for hepatocellular carcinoma (HCC) diagnosis in cirrhotic livers. In this review paper, we go over the basics of MR imaging in cirrhotic livers and describe the imaging appearance of a spectrum of hepatic nodules marking the progression from regenerative nodules to low- and high-grade dysplastic nodules, and ultimately to HCCs. We detail and illustrate the typical imaging appearances of different types of HCC including focal, multi-focal, massive, diffuse/infiltrative, and intra-hepatic metastases; with emphasis on the diagnostic value of MR in imaging these lesions. We also shed some light on liver imaging reporting and data system, and the role of different magnetic resonance imaging (MRI) contrast agents and future MRI techniques including the use of advanced MR pulse sequences and utilization of hepatocyte-specific MRI contrast agents, and how they might contribute to improving the diagnostic performance of MRI in early stage HCC diagnosis.

Safety assessment and therapeutic efficacy of percutaneous microwave ablation therapy combined with percutaneous ethanol injection for hepatocellular carcinoma adjacent to the gallbladder

OBJECTIVE

This study sought to evaluate the safety and efficacy of ultrasound-guided (US-guided) percutaneous microwave (MW) ablation combined with percutaneous ethanol injection (PEI) to treat liver tumours adjacent to the gallbladder.

MATERIALS AND METHODS

A total of 136 patients with hepatocellular carcinoma (HCC) adjacent to the gallbladder, who underwent ultra-sonographically-guided percutaneous MW ablation, which was combined with PEI in 132 patients, were retrospectively assessed. The patient population characteristics, tumour features, local tumour progression and treatment were compared and analysed. The safety and efficacy of the therapy were assessed by clinical data and imaging in follow-up examinations.

RESULTS

All patients were completely treated with two sessions; 120 patients underwent one session, 16 patients underwent two sessions. The primary technique was effective in 95.6% of the cases, according to the computed tomography (CT) or magnetic resonance imaging (MRI) in the one-month follow-up (132 of 138 sessions). PEI and other therapies were performed in the patients who had been incompletely treated (all six patients underwent PEI, and some underwent other therapies, including one transcatheter arterial chemoembolisation (TACE), one liver transplantation and two liver resections). There was a median follow-up period of 30.1 months and a range of 4 to 68 months. None of the patients had major complications. There were no treatment-related deaths. Twenty-six patients died of primary disease progression that was not directly attributable to MW ablation (19.1%, 26/136). Local tumour progression was noted in five patients (3.7%, 5/136), who had completely ablated tumours at follow-up. The patients with locally progressing tumours underwent additional therapy (three patients underwent PEI, one patient TACE, and one liver resection).

CONCLUSION

Ultrasound-guided percutaneous MW ablation, in combination with percutaneous ethanol injection and thermal monitoring, is a safe and effective treatment for HCC adjacent to the gallbladder.

Post-transplantation hepatocellular carcinoma recurrence: Patterns and relation between vascularity and differentiation degree

AIM: To evaluate the relationship between hepatocellular carcinoma (HCC) vascularity and grade; to describe patterns and vascular/histopathological variations of post-transplantation recurrence.

METHODS: This retrospective study included 165 patients (143 men, 22 women; median age 56.8 years, range 28-70.4 years) transplanted for HCC who had a follow-up period longer than 2 mo. Pre-transplantation dynamic computed tomography or magnetic resonance examinations were retrospectively reviewed, classifying HCC imaging enhancement pattern into hypervascular and hypovascular based on presence of wash-in during arterial phase. All pathologic reports of the explanted livers were reviewed, collecting data about HCC differentiation degree. The association between imaging vascular pattern and pathological grade was estimated using the Fisher exact test. All follow-up clinical and imaging data were reviewed for evidence of recurrence. Recurrence rate was calculated and imaging features of recurrent tumor were collected, classifying early and late recurrences based on timing (< or ≥ 2 years after transplantation) and intrahepatic, extrahepatic and both intrahepatic and extrahepatic recurrences based on location. All intrahepatic recurrences were classified as hypervascular or hypovascular and the differentiation degree was collected where available. The presence of variations in imaging enhancement pattern and pathological grade between the primary tumor and the intrahepatic recurrence was evaluated and the association between imaging and histopatholgical variations was estimated by using the χ² test.

RESULTS: Of the 163 patients with imaging evidence of viable tumor, 156 (95.7%) had hypervascular and 7 (4.3%) hypovascular HCC. Among the 125 patients with evidence of viable tumor in the explanted liver, 19 (15.2%) had grade 1, 56 (44.8%) grade 2, 40 (32%) grade 3 and 4 (3.2%) grade 4 HCC, while the differentiation degree was not assessable for 6 patients (4.8%). A significant association was found between imaging vascularity and pathological grade (P = 0.035). Post-transplantation recurrence rate was 14.55% (24/165). All recurrences occurred in patients who had a hypervascular primary tumor. Three patients (12.5%) experienced late recurrence; the location of the first recurrence was extrahepatic in 14 patients (58.3%), intrahepatic in 7 patients (29.2%) and both intrahepatic and extrahepatic in 3 patients (12.5%). Two patients had a variation in imaging characteristics between the primary HCC (hypervascular) and the intrahepatic recurrent HCC (hypovascular), while 1 patient had a variation of histopathological characteristics (from moderate to poor differentiation), however no association was found between imaging and histopathological variations.

CONCLUSION: A correlation was found between HCC grade and vascularity; some degree of variability may exist between the primary and the recurrence imaging/histopathological characteristics, apparently not correlated.

Liver Imaging Reporting and Data System with MR Imaging: Evaluation in Nodules 20 mm or Smaller Detected in Cirrhosis at Screening US

PURPOSE

To evaluate the diagnostic accuracy of the Liver Imaging Reporting and Data System (LI-RADS) with magnetic resonance (MR) imaging for hepatic nodules 20 mm or smaller detected during ultrasonographic (US) surveillance in patients with cirrhosis.

MATERIALS AND METHODS

Between November 2003 and January 2010, patients with cirrhosis with a newly US-detected solitary hepatic nodule 20 mm or smaller were included in this institutional ethics committee-approved study. All patients provided written informed consent before the study; the need to obtain consent for reanalysis of the data was waived. Patients underwent MR imaging and fine-needle biopsy (the reference standard). Nodules without pathologic confirmation were followed up with MR imaging every 6 months. A LI-RADS category was retrospectively assigned to nodules seen at MR imaging. The diagnostic accuracy for each LI-RADS category was described by sensitivity, specificity, and positive and negative predictive values with 95% confidence intervals.

RESULTS

Final diagnoses of 133 nodules in 159 patients were as follows: 102 hepatocellular carcinomas (HCCs), three intrahepatic cholangiocarcinomas (ICCs), one neuroendocrine metastasis, and 27 benign lesions (median MR imaging follow-up, 95 months). None (0%) of five LI-RADS category 1 lesions, three (25%) of 12 category 2 lesions, 29 (69%) of 42 category 3 lesions, 24 (96%) of 25 category 4 lesions, and 44 (98%) of 45 category 5 lesions were HCCs. One category 3 lesion was ICC, one category 5 lesion was a neuroendocrine metastasis, and two (50%) of four lesions categorized as other malignancies were HCCs. In patients with nodules detected at surveillance US, LI-RADS category 4 criteria were as effective as category 5 criteria for HCC diagnosis. Combining both categories would improve sensitivity without impairing specificity or positive or negative predictive value for HCC diagnosis (42.3%, 98.2%, 97.8%, and 47.4% vs 65.4%, 96.4%, 97.1%, and 59.6%, respectively).

CONCLUSION

In patients with cirrhosis with US-detected nodules 20 mm or smaller, both LI-RADS category 4 and category 5 have high specificity for HCC. In addition, a relevant proportion of lesions categorized as LI-RADS category 2 or 3 or as other malignancies were HCCs. Thus, active diagnostic work-up, including biopsy to allow prompt treatment, is recommended in such patients. Online supplemental material is available for this article.

Integrating contrast-enhanced sonography in the follow-up algorithm of hepatocellular carcinoma treated with radiofrequency ablation: single cancer center experience

BACKGROUND

Hepatocellular carcinoma (HCC) patients treated with percutaneous ablation require close follow-up for early detecting and treating tumor recurrence.

PURPOSE

To illustrate our single-center prospective experience on using contrast-enhanced ultrasound (CEUS) as a follow-up tool alternated with computed tomography (CT).

MATERIAL AND METHODS

In a 7-year period 588 patients with one to three HCCs were treated with radiofrequency ablation (alone or combined with ethanol injection). Patients with completely ablated tumors at 1-month CT scan were followed up serially, using alternated CEUS (one microbubbles injection per lobe) and CT every 3 months for 2 years. In few cases magnetic resonance imaging (MRI) was employed instead of or in addition to CT. The following patterns of recurrence were considered: A, enhancing tissue within the lesion; B, enhancing tissue adherent to the lesion; C, enhancing tissue within the same liver segment of the treated nodule; and D, enhancing tissue within a different segment. Patients with positive CEUS underwent confirmatory CT/MRI (standard reference).

RESULTS

Median follow-up was 19 months. There were 221 recurrences. Three pattern A recurrences (2 detected by CEUS and 1 by CT), 86 pattern B recurrences (44 detected by CEUS and 42 by CT), 70 pattern C recurrences (32 detected by CEUS and 38 by CT), and 62 pattern D recurrences (23 detected by CEUS and 39 by CT). CT detected additional nodules in 16/101 patients with positive CEUS.

CONCLUSION

CEUS follow-up of HCC patients after ablation is feasible. Since 72% recurrences develop in the same segment of the necrotic nodule, CEUS proves to be effective despite the minor visualization of the entire liver during the arterial phase when compared to CT and MRI. Including CEUS in patient follow-up may reduce the number of CT and MRI examinations.

Tumour-related neoangiogenesis: functional dynamic perfusion computed tomography for diagnosis and treatment efficacy assessment in hepatocellular carcinoma

BACKGROUND

Aim of the study was to determine the value of perfusion computed tomography in the quantitative assessment of tumour-related neoangiogenesis for the diagnosis and treatment of hepatocellular carcinoma lesions.

METHODS

Overall, 47 consecutive patients with cirrhotic liver disease, with a high risk of hepatocellular carcinoma, and undergoing standard surveillance (six-month intervals) were eligible for inclusion in this prospective study; based on Barcelona Clinic Liver Cancer guidelines, 27 patients were enrolled. Perfusion computed tomography was performed in 29 biopsy-proven hepatocellular carcinoma lesions before and after treatment with transarterial chemoembolization or radiofrequency ablation. The dynamic study was performed with a 256-slice multidetector-computed tomography scanner; the following parameters were measured: hepatic perfusion, arterial perfusion, blood volume, hepatic perfusion index, and time-to-peak in all patients.

RESULTS

Hepatocellular carcinoma lesions had the following median perfusion values: perfusion 46.3mL/min/100g; blood volume 20.4mL/100mg; arterial perfusion 42.9mL/min; hepatic perfusion index 92.5%; time to peak 18.7s. Significantly lower perfusion values were obtained in correctly treated lesions or surrounding parenchyma than in viable hepatocellular carcinoma tissue.

CONCLUSIONS

In hepatocellular carcinoma, perfusion computed tomography could contribute to a non-invasive quantification of tumour blood supply related to the formation of new arterial structures, and enable the assessment of therapeutic response.

Liver masses: a clinical, radiologic, and pathologic perspective

Liver masses present a relatively common clinical dilemma, particularly with the increasing use of various imaging modalities in the diagnosis of abdominal and other symptoms. The accurate and reliable determination of the nature of the liver mass is critical, not only to reassure individuals with benign lesions but also, and perhaps more importantly, to ensure that malignant lesions are diagnosed correctly. This avoids the devastating consequences of missed diagnosis and the delayed treatment of malignancy or the unnecessary treatment of benign lesions. With appropriate interpretation of the clinical history and physical examination, and the judicious use of laboratory and imaging studies, the majority of liver masses can be characterized noninvasively. Accurate characterization of liver masses by cross-sectional imaging is particularly dependent on an understanding of the unique phasic vascular perfusion of the liver and the characteristic behaviors of different lesions during multiphasic contrast imaging. When noninvasive characterization is indeterminate, a liver biopsy may be necessary for definitive diagnosis. Standard histologic examination usually is complemented by immunohistochemical analysis of protein biomarkers. Accurate diagnosis allows the appropriate selection of optimal management, which is frequently reassurance or intermittent follow-up evaluations for benign masses. For malignant lesions or those at risk of malignant transformation, management depends on the tumor staging, the functional status of the uninvolved liver, and technical surgical considerations. Unresectable metastatic masses require oncologic consultation and therapy. The efficient characterization and management of liver masses therefore requires a multidisciplinary collaboration between the gastroenterologist/hepatologist, radiologist, pathologist, hepatobiliary or transplant surgeon, and medical oncologist.

Liver transplantation for hepatocellular carcinoma: a surgical perspective

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality in the world. Early detection and timely treatment of HCC is critical for better patient outcomes. Curative therapy consists of surgical hepatic resection or liver transplantation (LTx); however, both are restricted to explicit selective criteria. Liver resection is the gold standard of treatment for noncirrhotic patients but can be done in only a small fraction of cirrhotic patients depending on synthetic dysfunction, degree of portal hypertension, and number and location(s) of tumor(s). Therefore, the best treatment modality in cirrhotic patients with HCC is LTx as it will cure both HCC and the underlying cirrhosis. The limitation to offer transplant to all cirrhotic patients with HCC is the shortage of available donor organs. While these patients are waiting for transplant, their tumors may progress and develop distant metastases and may lead to patients losing their candidacy for LTx. Various ablation therapies can be used to treat HCC, prevent tumor progression, and thus, avoid patients losing the option of LTx. Future directions to improve HCC patient outcomes include advancement in tumor gene analysis and histopathology for better prediction of tumor behavior, improved immunosuppression regimens to reduce tumor recurrence in the posttransplant setting, and efficient use of an expanded donor pool that includes living donor organs. This paper will review the current methods of HCC diagnosis, selection for either hepatic resection or LTx, and will also summarize posttreatment outcomes. We will suggest future directions for the field as we strive to improve outcomes for our HCC patients.

Gastrointestinal imaging: tips and traps in the diagnosis of small HCC

Improvement in survival of patients with HCC depends on detecting small lesions. This is possible by screening all patients with cirrhosis for HCC. However, these small lesions are difficult to characterise as only 50 to 80% of lesions less than 3cm have a typical HCC appearance, depending on the imaging technique used. MRI, with its various possibilities (dynamic sequences, diffusion-weighting, liver-specific contrast agents), is currently the most effective imaging technique for characterising these small HCCs, but at present we do not know the best combination of imaging examinations for diagnosing the condition.

LI-RADS: a case-based review of the new categorization of liver findings in patients with end-stage liver disease

Hepatocellular carcinoma (HCC) is a global health problem, with the burden of disease expected to increase in the coming years. Patients who are at increased risk for developing HCC undergo routine imaging surveillance, and once a focal abnormality is detected, evaluation with multiphasic contrast material-enhanced computed tomography or magnetic resonance imaging is necessary for diagnosis and staging. Currently, findings at liver imaging are inconsistently interpreted and reported by most radiologists. The Liver Imaging-Reporting and Data System (LI-RADS) is an initiative supported by the American College of Radiology that aims to reduce variability in lesion interpretation by standardizing report content and structure; improving communication with clinicians; and facilitating decision making (eg, for transplantation, ablative therapy, or chemotherapy), outcome monitoring, performance auditing, quality assurance, and research. Five categories that follow the diagnostic thought process are used to stratify individual observations according to the level of concern for HCC, with the most worrisome imaging features including a masslike configuration, arterial phase hyperenhancement, portal venous phase or later phase hypoenhancement, an increase of 10 mm or more in diameter within 1 year, and tumor within the lumen of a vein. LI-RADS continues to evolve and is expected to integrate a series of improvements in future versions that will positively affect the care of at-risk patients.

Intraoperative ultrasound in patients with hepatocellular carcinoma: from daily practice to future trends

Starting from the end of the 1970s, intraoperative ultrasound was introduced and developed to stage liver disease and guide the surgical interventions in patients with hepatocellular carcinoma. Without intraoperative ultrasound, it would probably be impossible to correctly define the hepatic segments as well as the limits of a tumor, also because of the existing wide variations in the anatomy. More importantly, intraoperative ultrasound allows for three-dimensional reconstruction of the relationships between the tumor, hepatic veins, and Glissonian pedicles. Such reconstruction is essential for planning the surgical strategy, which should be individualized in each patient with the aim to spare functional liver parenchyma. This work focuses on the role of intraoperative ultrasound to stage liver disease and to plan surgical resection, describing the most recent technical achievements.