LI-RADS 2017: An update

Development and Comparison of Prediction Models Based on Sonovue- and Sonazoid-Enhanced Ultrasound for Pathologic Grade and Microvascular Invasion in Hepatocellular Carcinoma

OBJECTIVE

This study was aimed at developing and comparing prediction models based on Sonovue and Sonazoid contrast-enhanced ultrasound (CEUS) in predicting pathologic grade and microvascular invasion (MVI) of hepatocellular carcinoma (HCC). Also investigated was whether Kupffer phase images have additional predictive value for the above pathologic features.

METHODS

Ninety patients diagnosed with primary HCC who had undergone curative hepatectomy were prospectively enrolled. All patients underwent conventional ultrasound (CUS), Sonovue-CEUS and Sonazoid-CEUS examinations pre-operatively. Clinical, radiologic and pathologic features including pathologic grade, MVI and CD68 expression were collected. We developed prediction models comprising clinical, CUS and CEUS (Sonovue and Sonazoid, respectively) features for pathologic grade and MVI with both the logistic regression and machine learning (ML) methods.

RESULTS

Forty-one patients (45.6%) had poorly differentiated HCC (p-HCC) and 37 (41.1%) were MVI positive. For pathologic grade, the logistic model based on Sonazoid-CEUS had significantly better performance than that based on Sonovue-CEUS (area under the curve [AUC], 0.929 vs. 0.848, p = 0.035), whereas for MVI, these two models had similar accuracy (AUC, 0.810 vs. 0.786, p = 0.068). Meanwhile, we found that well-differentiated HCC tended to have a higher enhancement ratio in 6-12 min during the Kupffer phase of Sonazoid-CEUS, as well as higher CD68 expression compared with p-HCC. In addition, all of these models can effectively predict the risk of recurrence (p < 0.05).

CONCLUSION

Sonovue-CEUS and Sonazoid-CEUS were comparably excellent in predicting MVI, while Sonazoid-CEUS was superior to Sonovue-CEUS in predicting pathologic grade because of the Kupffer phase. The enhancement ratio in the Kupffer phase has additional predictive value for pathologic grade prediction.

Revealing chronic disease progression patterns using Gaussian process for stage inference

OBJECTIVE

The early stages of chronic disease typically progress slowly, so symptoms are usually only noticed until the disease is advanced. Slow progression and heterogeneous manifestations make it challenging to model the transition from normal to disease status. As patient conditions are only observed at discrete timestamps with varying intervals, an incomplete understanding of disease progression and heterogeneity affects clinical practice and drug development.

MATERIALS AND METHODS

We developed the Gaussian Process for Stage Inference (GPSI) approach to uncover chronic disease progression patterns and assess the dynamic contribution of clinical features. We tested the ability of the GPSI to reliably stratify synthetic and real-world data for osteoarthritis (OA) in the Osteoarthritis Initiative (OAI), bipolar disorder (BP) in the Adolescent Brain Cognitive Development Study (ABCD), and hepatocellular carcinoma (HCC) in the UTHealth and The Cancer Genome Atlas (TCGA).

RESULTS

First, GPSI identified two subgroups of OA based on image features, where these subgroups corresponded to different genotypes, indicating the bone-remodeling and overweight-related pathways. Second, GPSI differentiated BP into two distinct developmental patterns and defined the contribution of specific brain region atrophy from early to advanced disease stages, demonstrating the ability of the GPSI to identify diagnostic subgroups. Third, HCC progression patterns were well reproduced in the two independent UTHealth and TCGA datasets.

CONCLUSION

Our study demonstrated that an unsupervised approach can disentangle temporal and phenotypic heterogeneity and identify population subgroups with common patterns of disease progression. Based on the differences in these features across stages, physicians can better tailor treatment plans and medications to individual patients.

Detection of arterial phase hyperenhancement of small hepatocellular carcinoma with MRI: Comparison between single arterial and multi-arterial phases and between extracellular and hepatospecific contrast agents

PURPOSE

The purpose of this study was to compare the detection rate of arterial phase hyperenhancement (APHE) in small hepatocellular carcinoma (HCC) between single arterial phase (single-AP) and triple hepatic arterial (triple-AP) phase MRI and between extracellular (ECA) and hepato-specific (HBA) contrast agents.

MATERIALS AND METHODS

A total of 109 cirrhotic patients with 136 HCCs from seven centers were included. There were 93 men and 16 women, with a mean age of 64.0 ± 8.9 (standard deviation) years (range: 42-82 years). Each patient underwent both ECA-MRI and HBA (gadoxetic acid)-MRI examination within one month of each other. Each MRI examination was retrospectively reviewed by two readers blinded to the second MRI examination. The sensitivities of triple- and single-AP for the detection of APHE were compared, and each phase of the triple-AP sequence was compared with the other two.

RESULTS

No differences in APHE detection were found between single-AP (97.2%; 69/71) and triple-AP (98.5%; 64/65) (P > 0.99) at ECA-MRI. No differences in APHE detection were found between single-AP (93%; 66/71) and triple-AP (100%; 65/65) at HBA-MRI (P = 0.12). Patient age, size of the nodules, use of automatic triggering, type of contrast agent, and type of sequence were not significantly associated with APHE detection. The reader was the single variable significantly associated with APHE detection. For triple-AP, best APHE detection rate was found for early and middle-AP images compared to late-AP images (P = 0.001 and P = 0.003). All APHEs were detected with the combination of early-AP and middle-AP images, except one that was detected on late-AP images by one reader.

CONCLUSION

Our study suggests that both single- and triple-AP can be used in liver MRI for the detection of small HCC especially when using ECA. Early AP and middle-AP are the most efficient phases and should be preferred for detecting APHE, regardless of the contrast agent used.

[CT/MRI Liver Imaging Reporting and Data System (LI-RADS): Standardization, Evidence, and Future Direction]

The liver imaging reporting and data system (LI-RADS) has been developed with the support of the American College of Radiology to standardize the diagnosis and evaluation of treatment response of hepatocellular carcinoma (HCC). The CT/MRI LI-RADS version 2018 has been incorporated in the American Association for the Study of Liver Diseases guidance. This review examines the effect of CT/MRI LI-RADS on the standardized reporting of liver imaging, and the evidence in diagnosing HCC and evaluating treatment response after locoregional treatment using CT/MRI LI-RADS. The results are compared with other HCC diagnosis guidelines, and future directions are described.

Liver Imaging Reporting and Data System criteria for the diagnosis of hepatocellular carcinoma in clinical practice: A pictorial minireview

Hepatocellular carcinoma (HCC) is the sixth most common cancer. The main risk factors associated with HCC development include hepatitis B virus, hepatitis C virus, alcohol consumption, aflatoxin B1, and nonalcoholic fatty liver disease. However, hepatocarcinogenesis is a complex multistep process. Various factors lead to hepatocyte malignant transformation and HCC development. Diagnosis and surveillance of HCC can be made with the use of liver ultrasound (US) every 6 mo. However, the sensitivity of this imaging method to detect HCC in a cirrhotic liver is limited, due to the abnormal liver parenchyma. Computed tomography (CT) and magnetic resonance imaging (MRI) are considered to be most useful tools for at-risk patients or patients with inadequate US. Liver biopsy is still used for diagnosis and prognosis of HCC in specific nodules that cannot be definitely characterized as HCC by imaging. Recently the American College of Radiology designed the Liver Imaging Reporting and Data System (LI-RADS), which is a comprehensive system for standardized interpretation of CT and MRI liver examinations that was first proposed in 2011. In 2018, it was integrated into the American Association for the Study of Liver Diseases guidance statement for HCC. LI-RADS is designed to ensure high sensitivity, precise categorization, and high positive predictive value for the diagnosis of HCC and is applied to “high-risk populations” according to specific criteria. Most importantly LI-RADS criteria achieved international collaboration and consensus among liver experts around the world on the best practices for caring for patients with or at risk for HCC.

A Narrative Review on LI-RADS Algorithm in Liver Tumors: Prospects and Pitfalls

Liver cancer is the sixth most detected tumor and the third leading cause of tumor death worldwide. Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with specific risk factors and a targeted population. Imaging plays a major role in the management of HCC from screening to post-therapy follow-up. In order to optimize the diagnostic-therapeutic management and using a universal report, which allows more effective communication among the multidisciplinary team, several classification systems have been proposed over time, and LI-RADS is the most utilized. Currently, LI-RADS comprises four algorithms addressing screening and surveillance, diagnosis on computed tomography (CT)/magnetic resonance imaging (MRI), diagnosis on contrast-enhanced ultrasound (CEUS) and treatment response on CT/MRI. The algorithm allows guiding the radiologist through a stepwise process of assigning a category to a liver observation, recognizing both major and ancillary features. This process allows for characterizing liver lesions and assessing treatment. In this review, we highlighted both major and ancillary features that could define HCC. The distinctive dynamic vascular pattern of arterial hyperenhancement followed by washout in the portal-venous phase is the key hallmark of HCC, with a specificity value close to 100%. However, the sensitivity value of these combined criteria is inadequate. Recent evidence has proven that liver-specific contrast could be an important tool not only in increasing sensitivity but also in diagnosis as a major criterion. Although LI-RADS emerges as an essential instrument to support the management of liver tumors, still many improvements are needed to overcome the current limitations. In particular, features that may clearly distinguish HCC from cholangiocarcinoma (CCA) and combined HCC-CCA lesions and the assessment after locoregional radiation-based therapy are still fields of research.

The diagnostic performance of contrast-enhanced CT versus extracellular contrast agent-enhanced MRI in detecting hepatocellular carcinoma: direct comparison and a meta-analysis

To compare the diagnostic value of contrast-enhanced computed tomography (CT) with extracellular contrast agent-enhanced magnetic resonance imaging (ECA-MRI) for the detection of hepatocellular carcinoma (HCC). Pubmed, Embase, Web of Science and Cochrane Library were searched (1/5/2021) for studies comparing contrast-enhanced CT with ECA-MRI in patients suspected of HCC. Studies without head-to-head comparison were excluded. The pooled sensitivity, specificity and summary area under the curve (sAUC) of contrast-enhanced CT and ECA-MRI in detecting HCC was calculated based on bivariate random effects model. Heterogeneity test included threshold effect analysis and meta-regression. Subgroup analyses were conducted according to lesion size (< 20 mm or ≥ 20 mm). Overall, 10 articles containing 1333 patients were deemed suitable for inclusion in this meta-analysis. ECA-MRI displayed increased sensitivity to contrast-enhanced CT in detecting HCC (0.77 vs. 0.63, P < 0.01). The difference in specificity between ECA-MRI and contrast-enhanced CT was not statistically significant (0.93 vs. 0.94, P = 0.25). ECA-MRI yielded higher diagnostic accuracy (sAUCs = 0.88 vs. 0.80, P < 0.01). In the subgroup analysis with a lesion size < 20 mm, ECA-MRI allowed significant gains of accuracy compared to contrast-enhanced CT (0.79 vs. 0.72, P = 0.02). ECA-MRI also outperformed contrast-enhanced CT in patients with lesion size ≥ 20 mm (sAUCs = 0.96 vs. 0.93, P = 0.04). ECA-MRI provided higher sensitivity and accuracy than contrast-enhanced CT in detecting HCC, especially lesions size < 20 mm.

Conventional, functional and radiomics assessment for intrahepatic cholangiocarcinoma

Background

This paper offers an assessment of diagnostic tools in the evaluation of Intrahepatic Cholangiocarcinoma (ICC).

Methods

Several electronic datasets were analysed to search papers on morphological and functional evaluation in ICC patients. Papers published in English language has been scheduled from January 2010 to December 2021.

Results

We found that 88 clinical studies satisfied our research criteria. Several functional parameters and morphological elements allow a truthful ICC diagnosis. The contrast medium evaluation, during the different phases of contrast studies, support the recognition of several distinctive features of ICC. The imaging tool to employed and the type of contrast medium in magnetic resonance imaging, extracellular or hepatobiliary, should change considering patient, departement, and regional features. Also, Radiomics is an emerging area in the evaluation of ICCs.

Post treatment studies are required to evaluate the efficacy and the safety of therapies so as the patient surveillance.

Conclusions

Several morphological and functional data obtained during Imaging studies allow a truthful ICC diagnosis.

Added Value of Quantitative Apparent Diffusion Coefficients for Identifying Small Hepatocellular Carcinoma from Benign Nodule Categorized as LI-RADS 3 and 4 in Cirrhosis

BACKGROUND AND AIMS

Correct identification of small hepatocellular carcinomas (HCCs) and benign nodules in cirrhosis remains challenging, quantitative apparent diffusion coefficients (ADCs) have shown potential value in characterization of benign and malignant liver lesions. We aimed to explore the added value of ADCs in the identification of small (≤3 cm) HCCs and benign nodules categorized as Liver Imaging Reporting and Data System (LI-RADS) 3 (LR-3) and 4 (LR-4) in cirrhosis.

METHODS

Ninety-seven cirrhosis patients with 109 small nodules (70 HCCs, 39 benign nodules) of LR-3 and 4 LR-4 based on major and ancillary magnetic resonance imaging features were included. Multiparametric quantitative ADCs of the lesions, including the mean ADC (ADC_mean), minimum ADC (ADC_min), maximal ADC (ADC_max), ADC standard deviation (ADC_std), and mean ADC value ratio of lesion-to-liver parenchyma (ADC_ratio) were calculated. Regarding the joint diagnosis, a nomogram model was plotted using multivariate logistic regression analysis. The performance was assessed using the area under the receiver operating characteristic curve (AUC).

RESULTS

The ADC_mean, ADC_min, ADC_ratio, and ADC_std were significantly associated with the identification of small HCC and benign nodules (p<0.001). For the joint diagnosis, the LI-RADS category (odds ratio [OR]=12.50), ADC_min (OR=0.14), and ADC_ratio (OR=0.12) were identified as independent factors for distinguishing HCCs from benign nodules. The joint nomogram model showed good calibration and discrimination, with a C-index of 0.947. Compared with the LI-RADS category alone, this nomogram model demonstrated a significant improvement in diagnostic performance, with AUC increasing from 0.820 to 0.967 (p=0.001).

CONCLUSIONS

The addition of quantitative ADCs could improve the identification of small HCC and benign nodules categorized as LR-3 and 4 LR-4 in patients with cirrhosis.

The Course of LIRADS 3 and 4 Hepatic Abnormalities as Correlated With Explant Pathology: A Single Center Experience

BACKGROUND AND AIMS

The Liver Reporting and Data System (LI-RADS) is the standard classification of imaging findings of hepatic abnormalities for hepatocellular carcinoma (HCC) surveillance. We aimed to study the course of LI-RADS 3 and 4 (LR-3 and LR-4) abnormalities through correlations with explant pathology.

METHODS

A single center retrospective study of liver transplant recipients between January 2016 and September 2019 with HCC on explant pathology was conducted. Eligible patients were divided into three subgroups based on their LI-RADS classification: LR-3/4, LR-5 only, and combination of LR-3/4/5.

RESULTS

There were 116 eligible patients with 99 LR-3/4 observations (60 LR-3 and 39 LR-4); the rest had LR-5 lesions. LR-4 more often than LR-3 observations progressed to LR-5 (36% vs 12%) and with shorter duration during follow-up (median 175 days and 196 days). Mean size growth of LR-3 and LR-4 abnormalities were 2.6 and 3.8 mm; median growth rates were 0.2 and 0.4 mm/month, respectively. Numbers of HCC lesions per explant, largest HCC lesion size, and cumulative size were higher in LR-3/4/5 subgroup than LR-5 subgroup (P = 0.007, 0.007 and 0.006, respectively); 68% of LR-3 and 82% of LR-4 abnormalities were confirmed HCC on explant (P = 0.09).

CONCLUSION

Compared to LR-3, more LR-4 abnormalities progressed to LR-5 (12% and 36%, respectively) in a shorter time and with faster growth rate. A high proportion of LR-3 and LR-4 lesions (68% and 82%, respectively) were confirmed HCC on explant, raising the question of whether excluding HCC based on radiologic criteria alone is adequate in those with LR-3/4 abnormalities.

Chronic Liver Disease and Liver Cancer: What the Hepatologists, Oncologists, and Surgeons Want to Know from Radiologists

Effective communication between radiologists and physicians involved in the management of patients with chronic liver disease is paramount to ensuring appropriate and advantageous incorporation of liver imaging findings into patient care. This review discusses the clinical benefits of innovations in radiology reporting, what information the various stakeholders wish to know from the radiologist, and how radiology can help to ensure the effective communication of findings.

Diagnostic evaluation and ablation treatments assessment in hepatocellular carcinoma

This article provides an overview of diagnostic evaluation and ablation treatment assessment in Hepatocellular Carcinoma (HCC). Only studies, in the English language from January 2010 to January 202, evaluating the diagnostic tools and assessment of ablative therapies in HCC patients were included. We found 173 clinical studies that satisfied the inclusion criteria.HCC may be noninvasively diagnosed by imaging findings. Multiphase contrast-enhanced imaging is necessary to assess HCC. Intravenous extracellular contrast agents are used for CT, while the agents used for MRI may be extracellular or hepatobiliary. Both gadoxetate disodium and gadobenate dimeglumine may be used in hepatobiliary phase imaging. For treatment-naive patients undergoing CT, unenhanced imaging is optional; however, it is required in the post treatment setting for CT and all MRI studies. Late arterial phase is strongly preferred over early arterial phase. The choice of modality (CT, US/CEUS or MRI) and MRI contrast agent (extracelllar or hepatobiliary) depends on patient, institutional, and regional factors. MRI allows to link morfological and functional data in the HCC evaluation. Also, Radiomics is an emerging field in the assessment of HCC patients.Postablation imaging is necessary to assess the treatment results, to monitor evolution of the ablated tissue over time, and to evaluate for complications. Post- thermal treatments, imaging should be performed at regularly scheduled intervals to assess treatment response and to evaluate for new lesions and potential complications.

Diagnostic Performance of Liver Imaging Reporting and Data System Version 2017 Versus Version 2018 for Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis of Comparative Studies

BACKGROUND

The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing liver imaging in patients at risk for hepatocellular carcinoma (HCC).

PURPOSE

To systematically compare the performance of computed tomography (CT)/MRI LI-RADS category 5 (LR-5) for diagnosing HCC between versions 2017 and 2018.

STUDY TYPE

Systematic review and meta-analysis.

SUBJECTS

Six articles with 1181 lesions.

FIELD STRENGTH/SEQUENCE

1.5 T and 3.0 T.

ASSESSMENT

Data extraction was independently performed by two reviewers who identified and reviewed articles comparing the performance of LR-5 for diagnosing HCC between CT/MRI LI-RADS versions 2017 and 2018. Study and patient characteristics, index test characteristics, reference standards, and study outcomes were extracted from included studies. Risk of bias and concerns regarding applicability were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

STATISTICAL TESTS

Bivariate random-effects models were used to calculate the pooled per-observation sensitivity and specificity of LR-5 using both versions. The summary receiver operating characteristic curves were plotted. Meta-regression analysis was performed to explore heterogeneity. A P-value <0.05 was considered to be statistically significant for all analyses other than heterogeneity, where the significance threshold was 0.1.

RESULTS

The pooled per-observation sensitivity of LR-5 for diagnosing HCC did not show statistically significant difference between versions 2017 (60%; 95% confidence interval [CI], 49%-70%) and 2018 (67%; 95% CI, 56%-76%; P = 0.381). The pooled per-observation specificities of LR-5 were not significantly different between versions 2017 (92%; 95% CI, 90%-95%) and 2018 (91%; 95% CI, 88%-93%; P = 0.332). Meta-regression analyses revealed that the most common underlying liver disease (hepatitis B or hepatitis C) was a significant factor contributing to the heterogeneity of sensitivities among studies for both versions.

DATA CONCLUSION

In this meta-analysis using intraindividual paired comparisons, the pooled sensitivity and pooled specificity of LR-5 were not significantly different between 2017 and 2018 LI-RADS versions.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Diagnosis of Non-Hepatocellular Carcinoma Malignancies in Patients With Risks for Hepatocellular Carcinoma: CEUS LI-RADS Versus CT/MRI LI-RADS

Objective

Data regarding direct comparison of contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) and Computed Tomography/Magnetic Resonance Imaging (CT/MR) LI-RADS in diagnosis of non-hepatocelluar carcinoma (non-HCC) malignancies remain limited. Our study aimed to compare the diagnostic performance of the CEUS LI-RADS version 2017 and CT/MRI LI-RADS v2018 for diagnosing non-HCC malignancies in patients with risks for HCC.

Materials and Methods

In this retrospective study, 94 liver nodules pathologically-confirmed as non-HCC malignancies in 92 patients at risks for HCC from January 2009 to December 2018 were enrolled. The imaging features and the LI-RADS categories on corresponding CEUS and CT/MRI within 1 month were retrospectively analyzed according to the ACR CEUS LI-RADS v2017 and ACR CT/MRI LI-RADS v2018 by two radiologists in consensus for each algorithm. The sensitivity of LR-M category, inter-reader agreement and inter-modality agreement was compared between these two standardized algorithms.

Results

Ninety-four nodules in 92 patients (mean age, 54 years ± 10 [standard deviation] with 65 men [54 years ± 11] and 27 women [54 years ± 8]), including 56 intrahepatic cholangiocarcinomas, 34 combined hepatocellular cholangiocarcinomas, two adenosquamous carcinomas of the liver, one primary hepatic neuroendocrine carcinoma and one hepatic undifferentiated sarcoma were included. On CEUS, numbers of lesions classified as LR-3, LR-4, LR-5 and LR-M were 0, 1, 10 and 83, and on CT/MRI, the corresponding numbers were 3, 0, 14 and 77. There was no significant difference in the sensitivity of LR-M between these two standardized algorithms (88.3% of CEUS vs 81.9% of CT/MRI, p = 0.210). Seventy-seven lesions (81.9%) were classified as the same LI-RADS categories by both standardized algorithms (five for LR-5 and 72 for LR-M, kappa value = 0.307). In the subgroup analysis for ICC and CHC, no significant differences were found in the sensitivity of LR-M category between these two standardized algorithms (for ICC, 94.6% of CEUS vs 89.3% of CT/MRI, p = 0.375; for CHC, 76.5% of CEUS vs 70.6% of CT/MRI, p = 0. 649).

Conclusion

CEUS LI-RADS v2017 and CT/MRI LI-RADS v2018 showed similar value for diagnosing non-HCC primary hepatic malignancies in patients with risks.

Differentiation of small (≤ 3 cm) hepatocellular carcinomas from benign nodules in cirrhotic liver: the added additive value of MRI-based radiomics analysis to LI-RADS version 2018 algorithm

Background

Accurate characterization of small nodules in a cirrhotic liver is challenging. We aimed to determine the additive value of MRI-based radiomics analysis to Liver Imaging Reporting and Data System version 2018 (LI-RADS v 2018) algorithm in differentiating small (≤ 3 cm) hepatocellular carcinomas (HCCs) from benign nodules in cirrhotic liver.

Methods

In this retrospective study, 150 cirrhosis patients with histopathologically confirmed small liver nodules (HCC, 112; benign nodules, 44) were evaluated from January 2013 to October 2018. Based on the LI-RADS algorithm, a LI-RADS category was assigned for each lesion. A radiomics signature was generated based on texture features extracted from T1-weighted, T2W, and apparent diffusion coefficient (ADC) images by using the least absolute shrinkage and selection operator regression model. A nomogram model was developed for the combined diagnosis. Diagnostic performance was assessed using receiver operating characteristic curve (ROC) analysis.

Results

A radiomics signature consisting of eight features was significantly associated with the differentiation of HCCs from benign nodules. Both LI-RADS algorithm (area under ROC [A_z] = 0.898) and the MRI-Based radiomics signature (A_z = 0.917) demonstrated good discrimination, and the nomogram model showed a superior classification performance (A_z = 0.975). Compared with LI-RADS alone, the combined approach significantly improved the specificity (97.7% vs 81.8%, p = 0.030) and positive predictive value (99.1% vs 92.9%, p = 0.031) and afforded comparable sensitivity (97.3% vs 93.8%, p = 0.215) and negative predictive value (93.5% vs 83.7%, p = 0.188).

Conclusions

MRI-based radiomics analysis showed additive value to the LI-RADS v 2018 algorithm for differentiating small HCCs from benign nodules in the cirrhotic liver.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01710-y.

Double Low-Dose Dual-Energy Liver CT in Patients at High-Risk of HCC: A Prospective, Randomized, Single-Center Study

OBJECTIVES

The aim of this study was to investigate the clinical feasibility of the simultaneous reduction of radiation and contrast doses using spectral computed tomography (CT) in patients at high-risk for hepatocellular carcinoma.

MATERIALS AND METHODS

Between May 2017 and March 2018, this prospective study recruited participants at risk of hepatocellular carcinoma with body mass indexes less than 30 and randomly assigned them to either the standard-dose group or the double low-dose group, which targeted 30% reductions in both radiation and contrast media (NCT03045445). Lesion conspicuity as a primary endpoint and lesion detection rates were then compared between hybrid iterative reconstruction (iDose) images of standard-dose group and low monoenergetic (50 keV) images of double low-dose group. Qualitative and quantitative image noise and contrast were also compared between the 2 groups. Participants and reviewers were blinded for scan protocols and reconstruction algorithms. Lesion conspicuity was analyzed using generalized estimating equation analysis. Lesion detection was evaluated using weighted jackknife alternative free-response receiver operating characteristic analysis.

RESULTS

Sixty-seven participants (male-to-female ratio, 59:8; mean age, 64 ± 9 years) were analyzed. Compared with the standard-dose group (n = 32), significantly lower CTDIvol (8.8 ± 1.7 mGy vs 6.1 ± 0.6 mGy) and contrast media (116.9 ± 15.7 mL vs 83.1 ± 9.9 mL) were utilized in the double low-dose group (n = 35; P < 0.001). Comparative analysis demonstrated that lesion conspicuity was significantly higher on 50 keV images of double low-dose group than on iDose images of standard dose on both arterial (2.62 [95% confidence interval (CI), 2.31-2.93] vs 2.02 [95% CI, 1.73-2.30], respectively, P = 0.004) and portal venous phases (2.39 [95% CI, 2.11-2.67] vs 1.88 [95% CI, 1.67-2.10], respectively, P = 0.005). No differences in lesion detection capability were observed between the 2 groups (figure of merit: 0.63 in standard-dose group; 0.65, double low-dose group; P = 0.52). Fifty kiloelectronvolt images of double low-dose group showed better subjective image noise and contrast than iDose image of standard-dose group on arterial and portal venous phases (P < 0.001 for all). Contrast-to-noise ratio of the aorta and portal vein was also higher in double low-dose group than in standard-dose group (P < 0.001 for all), whereas there was no significant difference of quantitative image noise between the 2 groups on arterial and portal phases (P = 0.4~0.5).

CONCLUSIONS

Low monoenergetic spectral CT images (50 keV) can provide better focal liver lesion conspicuity than hybrid iterative reconstruction image of standard-dose CT in nonobese patients while using lower radiation and contrast media doses.

Diagnostic accuracy of Liver Imaging Reporting and Data System locoregional treatment response criteria: a systematic review and meta-analysis

OBJECTIVE

There is increasing adoption of Liver Imaging Reporting and Data System (LI-RADS) treatment response (LR-TR) criteria. However, there is still a relative lack of evidence evaluating the performance of these criteria. We performed this study to assess the diagnostic accuracy of LI-RADS LR-TR criteria.

METHODS

A thorough search of PubMed, Embase, Scopus, and Cochrane Central Register of Controlled Trials for studies reporting diagnostic accuracy of LI-RADS LR-TR criteria was conducted through 30 June 2020. The meta-analytic summary of sensitivity, specificity, and diagnostic odds ratio of LI-RADS LR-TR criteria was computed using explant histopathology as the reference standard. The quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

Four studies were found eligible for meta-analysis. The total number of LR-TR observations was 462 (240 patients, 82.5% males). Different locoregional therapies (LRTs), including bland embolization, chemoembolization, radiofrequency ablation, and microwave ablation, had been used. The mean time interval between LRT and liver transplantation ranged from 181 to 219 days. There was a moderate to good inter-reader agreement for LR-TR criteria. The pooled sensitivity and specificity of LR-TR criteria for viable disease were 62% (95% CI, 49-74%; I² = 69%) and 87% (95% CI, 76-93%; I² = 57%), respectively. The pooled diagnostic odds ratio and area under the curve were 9.83 (95% CI, 5.34-18.08; I² = 19%) and 0.80.

CONCLUSIONS

LI-RADS LR-TR criteria have acceptable diagnostic performance for the diagnosis of viable tumor after LRT. Well-designed prospective studies evaluating criteria of equivocal lesions and effect of different LRTs should be performed.

KEY POINTS

• The pooled sensitivity and specificity of LI-RADS LR-TR criteria for the diagnosis of viable tumor were 62% and 87%, respectively. • The pooled diagnostic odds ratio and area under the curve were 9.83 and 0.80. • LR-TR criteria had a moderate to good inter-reader agreement.

Usefulness of the Contrast-Enhanced Ultrasound Liver Imaging Reporting and Data System in Diagnosing Focal Liver Lesions by Inexperienced Radiologists

OBJECTIVES

To evaluate the usefulness of the contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) in diagnosing focal liver lesions (FLLs) by inexperienced radiologists.

METHODS

Images and clinical data from 258 patients at risk for hepatocellular carcinoma who underwent CEUS were collected retrospectively. Two trained inexperienced radiologists and 2 experienced radiologists reviewed all CEUS clips. Each inexperienced radiologist assigned a CEUS LI-RADS category for each observation and labeled it benign or malignant independently. Each experienced radiologist labeled each lesion malignant or benign independently using a conventional diagnostic method. Interobserver agreement of CEUS LI-RADS was analyzed by the κ test. The overall diagnostic accuracy of the LI-RADS category and conventional diagnosis was described by the sensitivity, specificity, positive predictive value, and negative predictive value. All test results were considered significant at P < .05.

RESULTS

A κ value of 0.774 indicated that the CEUS LI-RADS algorithm resulted in substantial consistency between the inexperienced radiologists. For the diagnosis of hepatocellular carcinoma, the sensitivity, specificity, positive predictive value, and negative predictive value were improved significantly in inexperienced radiologists using the CEUS LI-RADS compared to conventional methods. The overall diagnostic accuracy of the experienced radiologists was almost equal to that of CEUS LI-RADS categories assigned by the inexperienced radiologists.

CONCLUSIONS

The CEUS LI-RADS algorithm can not only obtain substantial consistency among inexperienced radiologists but also have excellent diagnostic efficacy in the differentiation of benign from malignant FLLs compared to conventional methods. As a comprehensive algorithm, the CEUS LI-RADS can act as a guide for trainees in learning how to diagnose FLLs.

A New Diagnostic Criterion with Gadoxetic Acid-Enhanced MRI May Improve the Diagnostic Performance for Hepatocellular Carcinoma

BACKGROUND

To prospectively establish and validate new diagnostic criterion (DC) for liver-specific contrast agents and further compared the diagnostic sensitivity and specificity with conventional DC.

METHODS

Institutional Review Board approved and written informed consent were obtained for this prospective study. Two board-certified reviewers established the reference standard as hepatocellular carcinoma (HCC), non-HCC lesions by using marks on all cross-sectional MR images. Another 2 abdominal radiologists independently performed the marked lesion observations using 5 different DCs, including DC-1: arterial phase hyperenhancement (APHE) and portal venous phase washout; DC-2: APHE and hepatobiliary phase (HBP) hypointensity; DC-3: APHE and diffusion-weighted imaging (DWI) hyperintensity; DC-4: HBP hypointensity and DWI hyperintensity; DC-5: HBP hypointensity, DWI hyperintensity and excluded these markedly T2 hyperintensity. Diagnostic performance of sensitivity, specificity, and accuracy for each imaging DC was calculated, per-lesion diagnostic sensitivity and specificity of imaging criteria were compared by using McNemars test.

RESULTS

A total of 215 patients were included (mean age 53.82 ± 11.24 years; range 24-82 years) with 265 hepatic nodules (175 HCCs and 90 non-HCCs). The DC-4 (93.71%; 164/175) and DC-5 (92.57%; 162/175) yielded the highest diagnostic sensitivity and was better than DC-1 (72.57%; 127/175), DC-2 (82.86%; 145/175), and DC-3 (82.29%; 144/175) (all p < 0.001). The specificity of DC-1 (94.44%; 85/90) was significantly higher than that with DC-2 (83.33%; 75/90), DC-3 (84.44%; 76/90), DC-4 (74.44%; 67/90), and DC-5 (82.22%; 74/90) (all p < 0.05). Additionally, the DC-4 and DC-5 achieved the highest area under curve value of 0.841 (95% CI 0.783-0.899) and 0.874 (95% CI 0.822-0.925).

CONCLUSIONS

The combined use of HBP hypointensity and DWI hyperintensity as a new DC for HCC enables a high diagnostic sensitivity and comparable specificity.

Texture analysis of MR images to identify the differentiated degree in hepatocellular carcinoma: a retrospective study

Background

To explore the clinical value of texture analysis of MR images (multiphase Gd-EOB-DTPA-enhanced MRI and T2 weighted imaging (T2WI) to identify the differentiated degree of hepatocellular carcinoma (HCC).

Method

One hundred four participants were enrolled in this retrospective study. Each participant performed preoperative Gd-EOB-DTPA-enhanced MR scanning. Texture features were analyzed by MaZda, and B11 program was used for data analysis and classification. The diagnosis efficiencies of texture features and conventional imaging features in identifying the differentiated degree of HCC were assessed by receiver operating characteristic analysis. The relationship between texture features and differentiated degree of HCC was evaluated by Spearman’s correlation coefficient.

Results

The grey-level co-occurrence matrix -based texture features were most frequently extracted and the nonlinear discriminant analysis was excellent with the misclassification rate ranging from 3.33 to 14.93%. The area under the curve (AUC) of the combined texture features between poorly- and well-differentiated HCC, poorly- and moderately-differentiated HCC, moderately- and well-differentiated HCC was 0.812, 0.879 and 0.808 respectively, while the AUC of tumor size was 0.649, 0.660 and 0.517 respectively. The tumor size was significantly different between poorly- and moderately-HCC (p = 0.014). The COMBINE AUC values were not increased with tumor size combined.

Conclusions

Texture analysis of Gd-EOB-DTPA-enhanced MRI and T2WI was valuable and might be a promising method in identifying the differentiated degree of HCC. The poorly-differentiated HCC was more heterogeneous than well- and moderately-differentiated HCC.

Multimodality Imaging of Hepatocellular Carcinoma: From Diagnosis to Treatment Response Assessment in Everyday Clinical Practice

The Liver Imaging Reporting and Data System (LI-RADS) is a recently developed classification aiming to improve the standardization of liver imaging assessment in patients at risk of developing hepatocellular carcinoma (HCC). The LI-RADS v2017 implemented new algorithms for ultrasound (US) screening and surveillance, contrast-enhanced US diagnosis and computed tomography/magnetic resonance imaging treatment response assessment. A minor update of LI-RADS was released in 2018 to comply with the American Association for the Study of the Liver Diseases guidance recommendations. The scope of this review is to provide a practical overview of LI-RADS v2018 focused both on the multimodality HCC diagnosis and treatment response assessment.

Liver Imaging Reporting and Data System Version 2018: What Radiologists Need to Know

In this article, we aim to review Liver Imaging Reporting and Data System version 18 (LI-RADS v2018). Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy. Liver Imaging Reporting and Data System developed for standardizing interpreting, reporting, and data collection of HCC describes 5 major features for accurate HCC diagnosis and several ancillary features, some favoring HCC in particular or malignancy in general and others favoring benignity. Untreated hepatic lesions LI-RADS affords 8 unique categories based on imaging appearance on computed tomography and magnetic resonance imaging, which indicate the possibility of HCC or malignancy with or without tumor in vein. Furthermore, LI-RADS defines 4 treatment response categories for treated HCCs after different locoregional therapy. These continuous recent updates on LI-RADS improve the communication between the radiologists and the clinicians for better management and patient outcome.

Texture analysis of multi-phase MRI images to detect expression of Ki67 in hepatocellular carcinoma

AIM

To determine whether texture analysis of preoperative magnetic resonance imaging (MRI) images could be used to detect Ki67 expression, a widely used cell proliferation marker in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In total, 83 patients were included, 25 with low Ki67 (Ki67 ≤10%) HCC expression and 58 with high Ki67 (Ki67 ≥10%) HCC expression as demonstrated by retrospective surgical evaluation. All patients were examined using a 3 T MRI unit with one standard protocol. The region of interest was drawn manually by one radiologist. Texture analysis included histogram, co-occurrence matrix, run-length matrix, gradient, auto-regressive model, and wavelet transform features as calculated by MaZda (version 4.6; quantitative texture analysis software). The features reduced by the Fisher, probability of classification error, and average correlation coefficient (POE+ACC), mutual information were used to select the features that predicted Ki67 proliferation status with highest accuracy and then using the B11 program for data analysis and classification.

RESULTS

The misclassification rate of the principal component analysis (PCA) in the hepatobiliary phase (HBP), T2-weighted imaging (T2WI), arterial phase (AP), and portal vein phase (PVP) was 36/83 (43.37%), 35/82 (42.68%), 40/83 (48.19%), and 34/83 (40.96%), respectively. The misclassification of the linear discriminant analysis in HBP, T2WI, AP, and PVP phase was 13/83 (15.66%), 21/82 (25.61%), 9/83 (10.84%), and 8/83 (9.64%), respectively. The misclassification of the nonlinear discriminant analysis in HBP, T2WI, AP, and PVP phase was 7/83 (8.43%), 6/82 (7.32%), 5/83 (6.02%), and 7/83 (8.43%), respectively.

CONCLUSIONS

Texture analysis of HBP, AP, and PVP were helpful for predicting Ki67 expression and may provide a less-invasive method to investigate critical histopathology markers for HCC.

LI-RADS Treatment Response Algorithm: Performance and Diagnostic Accuracy

Background In 2017, the Liver Imaging Reporting and Data System (LI-RADS) included an algorithm for the assessment of hepatocellular carcinoma (HCC) treated with local-regional therapy. The aim of the algorithm was to enable standardized evaluation of treatment response to guide subsequent therapy. However, the performance of the algorithm has not yet been validated in the literature. Purpose To evaluate the performance of the LI-RADS 2017 Treatment Response algorithm for assessing the histopathologic viability of HCC treated with bland arterial embolization. Materials and Methods This retrospective study included patients who underwent bland arterial embolization for HCC between 2006 and 2016 and subsequent liver transplantation. Three radiologists independently assessed all treated lesions by using the CT/MRI LI-RADS 2017 Treatment Response algorithm. Radiology and posttransplant histopathology reports were then compared. Lesions were categorized on the basis of explant pathologic findings as either completely (100%) or incompletely (<100%) necrotic, and performance characteristics and predictive values for the LI-RADS Treatment Response (LR-TR) Viable and Nonviable categories were calculated for each reader. Interreader association was calculated by using the Fleiss κ. Results A total of 45 adults (mean age, 57.1 years ± 8.2; 13 women) with 63 total lesions were included. For predicting incomplete histopathologic tumor necrosis, the accuracy of the LR-TR Viable category for the three readers was 60%-65%, and the positive predictive value was 86%-96%. For predicting complete histopathologic tumor necrosis, the accuracy of the LR-TR Nonviable category was 67%-71%, and the negative predictive value was 81%-87%. By consensus, 17 (27%) of 63 lesions were categorized as LR-TR Equivocal, and 12 of these lesions were incompletely necrotic. Interreader association for the LR-TR category was moderate (κ = 0.55; 95% confidence interval: 0.47, 0.67). Conclusion The Liver Imaging Reporting and Data System 2017 Treatment Response algorithm had high predictive value and moderate interreader association for the histopathologic viability of hepatocellular carcinoma treated with bland arterial embolization when lesions were assessed as Viable or Nonviable. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Gervais in this issue.

The association between hepatocellular carcinoma and direct-acting anti-viral treatment in patients with decompensated cirrhosis

BACKGROUND

Direct-acting anti-viral therapy (DAA) has transformed hepatitis C virus (HCV) care, particularly in patients with decompensated cirrhosis. However, their impact on hepatocellular carcinoma (HCC) remains unclear.

AIM

To use a national registry of patients with advanced liver disease to explore the relationship between DAA therapy and HCC.

METHODS

All patients with de novo HCC post DAA therapy were frequency matched with patients who did not develop HCC. Demographic, clinical and laboratory data were obtained. Cross-sectional imaging and multidisciplinary team reports were reviewed for dates of HCC diagnosis and HCC progression. Patients were categorised by treatment outcome and time of HCC development. Data were examined by multivariable analysis and Kaplan-Meier estimation.

RESULTS

Eighty patients with HCC were compared with 165 patients without HCC, treated between June 2014 and September 2015. Mean follow-up from start of DAA therapy was 32.4 months. Twenty-eight patients were diagnosed with early HCC (within 6 months of therapy) and 52 presented late. Baseline nonmalignant lesions (HR: 1.99), thrombocytopaenia (HR: 1.59) and diabetes (HR: 1.68) increased likelihood of HCC. Response to therapy was reduced in patients who developed liver cancer (SVR in patients with HCC = 54/80 (68%), SVR in patients without HCC = 143/165 (87%), P < 0.001, OR: 3.13, 95% CI: 1.64-5.99). We found no difference between tumour size, progression or survival between viraemic and nonviraemic patients.

CONCLUSION

There is no alteration in prognosis or cancer progression following HCC development after HCV treatment. However, baseline nonmalignant liver lesions, diabetes and thrombocytopaenia increase the risk of HCC, and HCC is associated with a decreased SVR rate.

MR features based on LI-RADS identify cytokeratin 19 status of hepatocellular carcinomas

OBJECTIVE

To retrospectively evaluate the value of MR features based on Liver Imaging Reporting and Data System (LI-RADS ver.2017) for identifying the status of cytokeratin (CK) 19 expression of HCC before surgery.

METHODS

A total of 201 patients with 207 HCCs who underwent MR imaging were reviewed retrospectively. MR features based on LI-RADS ver.2017 as well as clinical data were compared between CK19-positive (n = 51) and CK19-negative (n = 156) HCCs groups. Potential predictive parameters were identified by univariate and multivariate logistic regression analysis and diagnostic odds ratios (ORs) were recorded.

RESULTS

MR features including targetoid appearance (p = 0.001) was more frequently observed while non-peripheral "washout" (p < 0.0001) and non-rim arterial phase hyper-enhancement (p < 0.0001) were found less frequently in CK19-positive HCCs compared to CK19-negative HCCs. At multivariate analysis, serum alphafetoprotein (AFP)>20 ng/ml (OR = 5.9) and targetoid appearance (OR = 4.2) and non-peripheral "washout" (OR = 0.2) were significant independent predictors of CK19-positive HCCs.

CONCLUSION

Targetoid appearance and absence non-peripheral "washout" combined with elevated AFP were useful for differentiating CK19-positive HCCs from CK19-negative HCC.

Comparison of gadoxetic acid versus gadopentetate dimeglumine for the detection of hepatocellular carcinoma at 1.5 T using the liver imaging reporting and data system (LI-RADS v.2017)

PURPOSE

The goal of this study was to investigate the Liver Imaging Reporting and Data System (LI-RADS) v.2017 for the categorization of hepatocellular carcinomas (HCCs) with gadoxetic acid compared with gadopentetate dimeglumine-enhanced 1.5-T magnetic resonance imaging (MRI).

MATERIAL AND METHODS

We included 141 high-risk patients with 145 pathologically-confirmed HCCs who first underwent gadopentetate dimeglumine-enhanced 1.5-T followed by gadoxetic acid-enhanced 1.5-T MRI. Two independent radiologists evaluated the presence or absence of major HCC features and assigned LI-RADS categories after considering ancillary features on both MRIs. Finally, the sensitivity of LI-RADS category 5 (LR-5) and the frequencies of major HCC features were compared between gadoxetic acid- and gadopentetate dimeglumine-enhanced 1.5-T MRI using the Wilcoxon test.

RESULTS

The sensitivity of LR-5 for diagnosing HCCs was significantly different between gadoxetic acid- and gadopentetate dimeglumine-enhanced MRI (73.8% [107/145] vs 26.2% [38/145], P < 0.001; 71% [103/145] vs 29% [42/145], P < 0.001 for reviewers 1 and 2, respectively). Among the major HCC LI-RADS features, capsule appearance was less frequently demonstrated on gadoxetic acid-enhanced MRI than on gadopentetate dimeglumine-enhanced MRI (3.4% [5/145] vs 5.5% [8/145], P = 0.793; 4.1% [6/145] vs 5.5% [8/145], P = 0.87 for reviewers 1 and 2, respectively), and the frequency of arterial hyperenhancement was not significantly different between gadoxetic acid and gadopentetate dimeglumine (89% [129/145] vs 89% [129/145], P = 1.000). In addition, the frequency of a washout appearance was less in the transitional phase (TP) than in the portal venous phase (PVP) on gadoxetic acid-enhanced MRI (43% [46/107] vs 57% [61/107], P = 0.367).

CONCLUSION

Gadoxetic acid-enhanced MRI showed a comparable sensitivity to gadopentetate dimeglumine-enhanced MRI for the diagnosis of HCCs, and LI-RADS category 4 (LR-4) hepatic nodules were upgraded to LR-5 when taking into account the major features according to LI-RADS v.2017.

Liver Imaging Reporting and Data System (LI-RADS) Version 2018: Imaging of Hepatocellular Carcinoma in At-Risk Patients

The Liver Imaging Reporting and Data System (LI-RADS) is composed of four individual algorithms intended to standardize the lexicon, as well as reporting and care, in patients with or at risk for hepatocellular carcinoma in the context of surveillance with US; diagnosis with CT, MRI, or contrast material-enhanced US; and assessment of treatment response with CT or MRI. This report provides a broad overview of LI-RADS, including its historic development, relationship to other imaging guidelines, composition, aims, and future directions. In addition, readers will understand the motivation for and key components of the 2018 update.

Retrospective validation of a new diagnostic criterion for hepatocellular carcinoma on gadoxetic acid-enhanced MRI: can hypointensity on the hepatobiliary phase be used as an alternative to washout with the aid of ancillary features?

OBJECTIVES

To validate new diagnostic criteria for hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MR imaging (Gd-EOB-MRI) using hypointensity on the hepatobiliary phase (HBP) as an alternative to washout in combination with ancillary features.

METHODS

This retrospective study included 288 patients at high risk for HCC with 387 nodules (HCCs, n=292; non-HCCs, n=95) showing arterial phase hyper-enhancement (APHE) ≥1 cm on Gd-EOB-MRI. Imaging diagnoses of HCCs were made using different criteria: APHE plus hypointensity on the portal venous phase (PVP) (criterion 1), APHE plus hypointensity on the PVP and/or transitional phase (TP) (criterion 2), APHE plus hypointensity on the PVP and/or TP and/or HBP (criterion 3), and criterion 3 plus non-LR-1/2/M according to the Liver Imaging Reporting and Data System (LI-RADS) v2017 considering ancillary features (criterion 4). Sensitivities and specificities of those criteria were compared using McNemar's test.

RESULTS

Among diagnostic criteria for HCCs, criteria 3 and 4 showed significantly higher sensitivities (93.8% and 92.5%, respectively) than criteria 1 and 2 (70.9% and 86.6%, respectively) (p values <0.001). The specificity of criterion 4 (87.4%) was shown to be significantly higher than that of criterion 3 (48.4%, p<0.001), albeit comparable to criterion 2 (86.3%, p>0.999) and significantly lower than criterion 1 (97.9%, p=0.002).

CONCLUSIONS

In the non-invasive diagnosis of HCCs on Gd-EOB-MRI, HBP hypointensity may be used as an alternative to washout enabling a highly sensitive diagnosis with little loss in specificity if it is used after excluding nodules considered to be benignities or non-HCC malignancies based on characteristic imaging features.

KEY POINTS

• Gd-EOB-MRI enhancement and ancillary features can be used to diagnose HCC. • Exclusion of LR-1/2/M improves specificity when HBP hypointensity is used.

68Ga-PSMA is a novel PET-CT tracer for imaging of hepatocellular carcinoma: A prospective pilot study

Background:⁶⁸Ga-Prostate Specific Membrane Antigen (⁶⁸Ga-PSMA), a positron emission tomography (PET) tracer that was recently introduce for imaging of prostate cancer, may accumulate in other solid tumors including Hepatocellular Carcinoma (HCC). The aim of the study was to assess the potential role of ⁶⁸Ga-PSMA PET-Computed Tomography (CT) for imaging of HCC. Material and Methods: A prospective pilot study in seven patients with HCC with 41 liver lesions: 37 suspected malignant lesions (tumor lesions) and 4 regenerative nodules. For each liver lesion, uptake of ⁶⁸Ga-PSMA and ¹⁸F-FDG uptake were measured [standard uptake value (SUV) and lesion-to-liver background ratios (TBR-SUV)], and correlated with dynamic characteristics (HU and TBR-HU) obtained on contrast enhanced CT data. Immunohistochemistry staining of PSMA in the tumor tissue was analyzed in samples obtained from 5 patients with HCC and compared to control samples from 3 patients with prostate cancer. Results: Thirty-six of the 37 tumor lesions and none of the regenerative nodules showed increased ⁶⁸Ga-PSMA uptake while only 10 lesions were ¹⁸F-FDG avid. Based on contrast enhancement, tumor lesions were categorized into 27 homogeneously enhancing lesions, nine lesions with "mosaic" enhancement composed of enhancing and non-enhancing regions in the same lesion and a single non-enhancing lesion, the latter being the only non-⁶⁸Ga-PSMA avid lesion. Using the Mann-Whitney test, ⁶⁸Ga-PSMA uptake was found significantly higher in enhancing tumor areas compared to non-enhancing areas and in contrast, ¹⁸F-FDG uptake was higher in non-enhancing areas, P<0.001 for both. ⁶⁸Ga-PSMA uptake (TBR SUV_max) was found to correlate with vascularity (TBR-HU) (Spearman r=0.866, p<0.001). Immunohistochemistry showed intense intra-tumoral microvessel staining for PSMA in HCC, in contrast with cytoplasmic and membranous staining, mainly in the luminal border, in prostate cancer samples. In two of the study patients ⁶⁸Ga-PSMA PET-CT identified unexpected extrahepatic metastases. Four regenerative liver nodules showed no increased uptake of either of the PET tracers. Conclusion:⁶⁸Ga-PSMA PET-CT is superior to ¹⁸F-FDG PET-CT in imaging patients with HCC. HCC lesions are more commonly hypervascular taking up ⁶⁸Ga-PSMA in tumoral micro-vessels. ⁶⁸Ga-PSMA PET-CT is a potential novel modality for imaging patients with HCC.