Evidence Supporting LI-RADS Major Features for CT- and MR Imaging-based Diagnosis of Hepatocellular Carcinoma: A Systematic Review

LI-RADS Major Features on MRI for Diagnosing Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

The reported diagnostic performance for hepatocellular carcinoma (HCC) of each major imaging feature on MRI using standardized definitions of the Liver Imaging Reporting and Data System (LI-RADS) is variable. It is important to know the actual performance of each LI-RADS major imaging feature for imaging diagnosis of HCC and determine the sources of heterogeneity between the reported results.

PURPOSE

To systematically determine the performance of each major imaging feature of LI-RADS for diagnosing HCC using either extracellular contrast agent-enhanced MRI (ECA-MRI) or gadoxetate disodium-enhanced MRI (EOB-MRI).

STUDY TYPE

Systematic review and meta-analysis.

SUBJECTS

Sixteen original articles with 3542 lesions.

FIELD STRENGTH

A 1.5 T and 3.0 T.

ASSESSMENT

Data extraction was independently performed by two reviewers who identified and reviewed original articles reporting the diagnostic performance of each LI-RADS major imaging feature-arterial phase hyperenhancement (APHE), observation size, washout appearance, enhancing "capsule," and threshold growth-using MRI. Study characteristics, study population characteristics, MRI characteristics, contrast agent, LI-RADS version, 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 obtain summary estimates of the diagnostic performance of each LI-RADS major imaging feature. Hierarchical summary receiver operating characteristic curves were plotted. Meta-regression analyses were performed to explore potential sources of heterogeneity.

RESULTS

The pooled per-observation sensitivities and specificities for diagnosing HCC were 85% (95% confidence interval [CI] = 78%-89%) and 57% (95% CI = 44%-70%) for arterial phase hyperenhancement (APHE), 77% (95% CI = 72%-82%), and 74% (95% CI = 63%-83%) for washout appearance, and 52% (95% CI = 41%-64%) and 90% (95% CI = 85%-94%) for enhancing "capsule," respectively.

DATA CONCLUSIONS

Among the LI-RADS major features, the sensitivity was the highest for APHE and the specificity was the highest for enhancing "capsule" in the diagnosis of HCC.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Liver Imaging Reporting and Data System Comprehensive Guide: MR Imaging Edition

The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing the lexicon, technique, interpretation, reporting, and data collection of liver imaging. Developed specifically for assessment of liver observations in patients at risk for hepatocellular carcinoma (HCC), LI-RADS classifies hepatic observations on the basis of the probability of their being HCC, from LR-1 (definitely benign) to LR-5 (definitely HCC). This article discusses the technical requirements, major features, and ancillary features of and a systematic approach for using the LI-RADS diagnostic algorithm, with special emphasis on MR imaging.

MR Imaging Contrast Agents: Role in Imaging of Chronic Liver Diseases

Contrast-enhanced MR imaging plays an important role in the evaluation of patients with chronic liver disease, particularly for detection and characterization of liver lesions. The two most commonly used contrast agents for liver MR imaging are extracellular agents (ECAs) and hepatobiliary agents (HBAs). In patients with liver disease, the main advantage of ECA-enhanced MR imaging is its high specificity for the diagnosis of progressed HCCs. Conversely, HBAs have an additional contrast mechanism, which results in high liver-to-lesion contrast and highest sensitivity for lesion detection in the hepatobiliary phase. Emerging data suggest that features depicted on contrast-enhanced MR imaging scans are related to tumor biology and are predictive of patients' prognosis, likely to further expand the role of contrast-enhanced MR imaging in the clinical care of patients with chronic liver disease.

Errors and Misinterpretations in Imaging of Chronic Liver Diseases

MRI is an important problem-solving tool for accurate characterization of liver lesions. Chronic liver disease alters the typical imaging characteristics and complicates liver imaging. Awareness of imaging pitfalls and technical artifacts and ways to mitigate them allows for more accurate and timely diagnosis.

Atypical presentation of a locally advanced hepatocellular carcinoma: Extensive workup of an incidental finding on computed tomography performed for planning of transcatheter aortic valve implantation

This case report presents the diagnostic workup of liver malignancy incidentally detected in a 72-year-old male patient on routine body computed tomography angiography (CTA) performed for planning transcatheter aortic valve implantation (TAVI).

The patient initially presented to an outside hospital with chest discomfort, where routine diagnostic procedures in the emergency room revealed grade III aortic valve stenosis.

Routine CTA for TAVI planning in our department then revealed tumor thrombosis of the portal vein suspicious for hepatic malignancy.

In contrast-enhanced ultrasound (CEUS) only the left hepatic lobe was inhomogeneously transformed with early arterial contrast enhancement. Magnetic resonance imaging (MRI) confirmed a primary hepatic malignancy involving the left liver. Transcutaneous biopsy with ultrasound guidance established the diagnosis of hepatocellular carcinoma (HCC).

Incidental findings may be of prognostic relevance for the patient and in a number of cases, TAVI can be a prerequisite for the appropriate therapy.

Diagnosis of LI-RADS M lesions on gadoxetate-enhanced MRI: identifying cholangiocarcinoma-containing tumor with serum markers and imaging features

OBJECTIVES

The LI-RADS M (LR-M) category describes hepatic lesions probably or definitely malignant, but not specific for hepatocellular carcinoma in at-risk patients. Differentiation among LR-M entities, particularly detecting cholangiocarcinoma-containing tumors (M-CCs), is essential for treatment and prognosis. Thus, we aimed to develop diagnostic models on gadoxetate disodium-enhanced MRI comprising serum tumor markers and LI-RADS imaging features for M-CC.

METHODS

Consecutive at-risk patients with LR-M lesions exclusively (no co-existing LR-4 and/or LR-5 lesions) were retrieved retrospectively from a prospectively collected database spanning 3 years. Intrahepatic cholangiocarcinoma (ICC) and combined hepatocellular-cholangiocarcinoma (c-HCC-CCA) were classified together as M-CC. LI-RADS features determined by three independent radiologists and clinically relevant serum tumor markers were used to generate M-CC diagnostic models through logistic regression analysis against histology. Per-patient performance was evaluated using area under the receiver operating curve (AUC), sensitivity, and specificity.

RESULTS

Forty-five patients were included, 42.2% (19/45) with hepatocellular carcinoma, 33.3% (15/45) with ICC, 13.3% (6/45) with c-HCC-CCA, and 11.1% (5/45) with other hepatic lesions. Carbohydrate antigen (CA)19-9 > 38 U/mL, α-fetoprotein (AFP) > 4.8 ng/mL, and absence of the LI-RADS feature "blood products in mass" were significant predictors of M-CC. Combining three predictors demonstrated AUC of 0.862, sensitivity of 76%, and specificity of 88%. The risk of M-CC with all three criteria fulfilled was 98% (AUC, 0.690; sensitivity, 38%; specificity, 100%).

CONCLUSIONS

In at-risk patients with LR-M lesions, integrating CA19-9, AFP, and the LI-RADS feature "blood products in mass" achieved high diagnostic performance for M-CC. When all three criteria were fulfilled, the specificity for M-CC was 100%.

KEY POINTS

• In at-risk patients who had LR-M lesions exclusively (no concomitant LR-4/5 lesions), a model with carbohydrate antigen > 38 U/mL, α-fetoprotein > 4.8 ng/mL, and absence of the LI-RADS feature "blood products in mass" achieved high accuracy for diagnosing cholangiocarcinoma-containing tumors. • In patients of whom all three criteria were fulfilled, the specificity for M-CC was 100%, which might reduce or eliminate the need for biopsy confirmation.

Expression of Cancer Testis Antigens in Tumor-Adjacent Normal Liver Is Associated with Post-Resection Recurrence of Hepatocellular Carcinoma

Simple Summary

High recurrence rates after resection of liver cancer (hepatocellular carcinoma) with curative intent impair clinical outcomes of patients diagnosed with liver cancer. Cancer/testis antigens (CTAs) are expressed in cancer and can serve as therapeutic targets. We identified 12 CTAs expressed in 80% of liver cancer patients, and each one individually in at least 10%. Furthermore, we found that patients with expression of CTAs in macroscopically tumor-free liver tissue, experience more tumor recurrence and poor survival after surgical tumor removal. The increased risk of tumor recurrence in patients with CTA expression in tumor-free liver suggests that these patients already have micro-metastasis at the time of operation. These CTA-expressing (pre-)malignant cells may thus be a source of liver cancer recurrence, reflecting the relevance of targeting these to prevent liver cancer recurrence.

Abstract

High recurrence rates after resection of hepatocellular carcinoma (HCC) with curative intent impair clinical outcomes of HCC. Cancer/testis antigens (CTAs) are suitable targets for cancer immunotherapy if selectively expressed in tumor cells. The aims were to identify CTAs that are frequently and selectively expressed in HCC-tumors, and to investigate whether CTAs could serve as biomarkers for occult metastasis. Tumor and paired tumor-free liver (TFL) tissues of HCC-patients and healthy tissues were assessed for mRNA expression of 49 CTAs by RT-qPCR and protein expression of five CTAs by immunohistochemistry. Twelve CTA-mRNAs were expressed in ≥10% of HCC-tumors and not in healthy tissues except testis. In tumors, mRNA and protein of ≥ 1 CTA was expressed in 78% and 71% of HCC-patients, respectively. In TFL, CTA mRNA and protein was found in 45% and 30% of HCC-patients, respectively. Interestingly, CTA-expression in TFL was an independent negative prognostic factor for post-resection HCC-recurrence and survival. We established a panel of 12 testis-restricted CTAs expressed in tumors of most HCC-patients. The increased risk of HCC-recurrence in patients with CTA expression in TFL, suggests that CTA-expressing (pre-)malignant cells may be a source of HCC-recurrence, reflecting the relevance of targeting these to prevent HCC-recurrence.

Diagnosis and treatment of hepatocellular carcinoma. Update of the consensus document of the AEEH, AEC, SEOM, SERAM, SERVEI, and SETH

Hepatocellular carcinoma (HCC) is the most common primary liver neoplasm and one of the most common causes of death in patients with cirrhosis of the liver. In parallel, with recognition of the clinical relevance of this cancer, major new developments have recently appeared in its diagnosis, prognostic assessment and in particular, in its treatment. Therefore, the Spanish Association for the Study of the Liver (AEEH) has driven the need to update the clinical practice guidelines, once again inviting all the societies involved in the diagnosis and treatment of this disease to participate in the drafting and approval of the document: Spanish Society for Liver Transplantation (SETH), Spanish Society of Diagnostic Radiology (SERAM), Spanish Society of Vascular and Interventional Radiology (SERVEI), Spanish Association of Surgeons (AEC) and Spanish Society of Medical Oncology (SEOM). The clinical practice guidelines published in 2016 and accepted as National Health System Clinical Practice Guidelines were taken as the reference documents, incorporating the most important recent advances. The scientific evidence and the strength of the recommendation is based on the GRADE system.

CT/MRI LI-RADS v2018 vs. CEUS LI-RADS v2017-Can Things Be Put Together?

Different LI-RADS core documents were released for CEUS and for CT/MRI. Both documents rely on major and ancillary diagnostic criteria. The present paper offers an exhaustive comparison of the two documents focusing on the similarities, but especially on the differences, complementarity, and added value of imaging techniques in classifying liver nodules in cirrhotic livers. The major diagnostic criteria are defined, and the sensitivity and specificity of each major diagnostic criteria are presented according to the literature. The existing differences between techniques in assessing the major diagnostic features can be then exploited in order to ensure a better classification and a better clinical management of liver nodules in cirrhotic livers. Ancillary features depend on the imaging technique used, and their presence can upgrade or downgrade the LI-RADS score of an observation, but only as far as LI-RADS 4. MRI is the imaging technique that provides the greatest number of ancillary features, whereas CEUS has fewer ancillary features than other imaging techniques. In the final part of the manuscript, some recommendations are made by the authors in order to guidephysicians as to when adding another imaging technique can be helpful in managing liver nodules in cirrhotic livers.

Hepatobiliary Cancers, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Hepatobiliary Cancers focus on the screening, diagnosis, staging, treatment, and management of hepatocellular carcinoma (HCC), gallbladder cancer, and cancer of the bile ducts (intrahepatic and extrahepatic cholangiocarcinoma). Due to the multiple modalities that can be used to treat the disease and the complications that can arise from comorbid liver dysfunction, a multidisciplinary evaluation is essential for determining an optimal treatment strategy. A multidisciplinary team should include hepatologists, diagnostic radiologists, interventional radiologists, surgeons, medical oncologists, and pathologists with hepatobiliary cancer expertise. In addition to surgery, transplant, and intra-arterial therapies, there have been great advances in the systemic treatment of HCC. Until recently, sorafenib was the only systemic therapy option for patients with advanced HCC. In 2020, the combination of atezolizumab and bevacizumab became the first regimen to show superior survival to sorafenib, gaining it FDA approval as a new frontline standard regimen for unresectable or metastatic HCC. This article discusses the NCCN Guidelines recommendations for HCC.

Corona enhancement can substitute enhancing capsule in the imaging diagnosis of small (≤ 3 cm) HCCs on gadoxetic acid-enhanced MRI

OBJECTIVES

This study aimed to elucidate the relationship between gadoxetic acid-enhanced magnetic resonance imaging (MRI) features-enhancing capsule, corona enhancement or hypointense rim-observed in hepatocellular carcinomas (HCCs).

METHODS

Of the HCCs surgically confirmed during a 5-year period (2013-2017), ≤ 3-cm lesions (n = 83) in 78 patients were evaluated. Presence of corona enhancement and enhancing capsule on multiphasic dynamic imaging and presence of hypointense rim on hepatobiliary phase imaging were determined retrospectively by two independent observers. The relationship among the three imaging features was statistically analysed and correlated with the presence of histologic fibrous capsules, tumour differentiation and gross morphologic type.

RESULTS

There was substantial overall interobserver agreement in determining the presence of the three imaging features. Sixty (72.3%) lesions had histologic fibrous capsule positively correlated with all three imaging features (p < 0.05). Corona enhancement was the most common (66.3%) feature followed by enhancing capsule (61.4%) and hypointense rim (33.7%), and the correspondence rate of enhancing capsule to corona enhancement was 68.6% (p = 0.004). Corona enhancement was more frequently observed in moderately differentiated HCCs than other lesions (p = 0.012) and not dependent (p = 0.465) on the tumour size, while enhancing capsule was significantly dependent on tumour size, as indicated by univariate (p < 0.001) and multivariate analyses (odds ratio, 4.241; p = 0.002).

CONCLUSIONS

Among the capsular features, corona enhancement might closely relate to enhancing capsule in HCCs. Corona enhancement was not dependent on tumour size and had the highest incidence of appearance on gadoxetic acid-enhanced multiphasic dynamic MRI.

KEY POINTS

• Enhancing capsule has a limited role in the LI-RADS categorisation during gadoxetic acid-enhanced MRI. • Appearance of corona enhancement is closely related to enhancing capsule and is not dependent on size of HCCs. • Corona enhancement can substitute enhancing capsule in the diagnosis of HCCs during multiple arterial and portal venous phase gadoxetic acid-enhanced MRI.

Percutaneous Irreversible Electroporation for Treatment of Small Hepatocellular Carcinoma Invisible on Unenhanced CT: A Novel Combined Strategy with Prior Transarterial Tumor Marking

INTRODUCTION

To explore the feasibility, safety, and efficiency of ethiodized oil tumor marking combined with irreversible electroporation (IRE) for small hepatocellular carcinomas (HCCs) that were invisible on unenhanced computed tomography (CT).

METHODS

A retrospective analysis of the institutional database was performed from January 2018 to September 2018. Patients undergoing ethiodized oil tumor marking to improve target-HCC visualization in subsequent CT-guided IRE were retrieved. Target-HCC visualization after marking was assessed, and the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNR) were compared between pre-marking and post-marking CT images using the paired t-test. Standard IRE reports, adverse events, therapeutic endpoints, and survival were summarized and assessed.

RESULTS

Nine patients with 11 target-HCCs (11.1-18.8 mm) were included. After marking, all target-HCCs demonstrated complete visualization in post-marking CT, which were invisible in pre-marking CT. Quantitatively, the SNR of the target-HCCs significantly increased after marking (11.07 ± 4.23 vs. 3.36 ± 1.79, p = 0.006), as did the CNR (4.32 ± 3.31 vs. 0.43 ± 0.28, p = 0.023). In sequential IRE procedures, the average current was 30.1 ± 5.3 A, and both the delta ampere and percentage were positive with the mean values of 5.8 ± 2.1 A and 23.8 ± 6.3%, respectively. All procedures were technically successful without any adverse events. In the follow-up, no residual unablated tumor (endpoint-1) was observed. The half-year, one-year, and two-year local tumor progression (endpoint-2) rate was 0%, 9.1%, and 27.3%. The two-year overall survival rate was 100%.

CONCLUSIONS

Ethiodized oil tumor marking enables to demarcate small HCCs that were invisible on unenhanced CT. It potentially allows a safe and complete ablation in subsequent CT-guided IRE.

Identification of Tumor-Specific MRI Biomarkers Using Machine Learning (ML)

The identification of reliable and non-invasive oncology biomarkers remains a main priority in healthcare. There are only a few biomarkers that have been approved as diagnostic for cancer. The most frequently used cancer biomarkers are derived from either biological materials or imaging data. Most cancer biomarkers suffer from a lack of high specificity. However, the latest advancements in machine learning (ML) and artificial intelligence (AI) have enabled the identification of highly predictive, disease-specific biomarkers. Such biomarkers can be used to diagnose cancer patients, to predict cancer prognosis, or even to predict treatment efficacy. Herein, we provide a summary of the current status of developing and applying Magnetic resonance imaging (MRI) biomarkers in cancer care. We focus on all aspects of MRI biomarkers, starting from MRI data collection, preprocessing and machine learning methods, and ending with summarizing the types of existing biomarkers and their clinical applications in different cancer types.

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.

R2* value derived from multi-echo Dixon technique can aid discrimination between benign and malignant focal liver lesions

BACKGROUND

R2* estimation reflects the paramagnetism of the tumor tissue, which may be used to differentiate between benign and malignant liver lesions when contrast agents are contraindicated.

AIM

To investigate whether R2* derived from multi-echo Dixon imaging can aid differentiating benign from malignant focal liver lesions (FLLs) and the impact of 2D region of interest (2D-ROI) and volume of interest (VOI) on the outcomes.

METHODS

We retrospectively enrolled 73 patients with 108 benign or malignant FLLs. All patients underwent conventional abdominal magnetic resonance imaging and multi-echo Dixon imaging. Two radiologists independently measured the mean R2* values of lesions using 2D-ROI and VOI approaches. The Bland-Altman plot was used to determine the interobserver agreement between R2* measurements. Intraclass correlation coefficient (ICC) was used to determine the reliability between the two readers. Mean R2* values were compared between benign and malignant FFLs using the nonparametric Mann-Whitney test. Receiver operating characteristic curve analysis was used to determine the diagnostic performance of R2* in differentiation between benign and malignant FFLs. We compared the diagnostic performance of R2* measured by 2D-ROI and VOI approaches.

RESULTS

This study included 30 benign and 78 malignant FLLs. The interobserver reproducibility of R2* measurements was excellent for the 2D-ROI (ICC = 0.994) and VOI (ICC = 0.998) methods. Bland-Altman analysis also demonstrated excellent agreement. Mean R2* was significantly higher for malignant than benign FFLs as measured by 2D-ROI (P < 0.001) and VOI (P < 0.001). The area under the curve (AUC) of R2* measured by 2D-ROI was 0.884 at a cut-off of 25.2/s, with a sensitivity of 84.6% and specificity of 80.0% for differentiating benign from malignant FFLs. R2* measured by VOI yielded an AUC of 0.875 at a cut-off of 26.7/s in distinguishing benign from malignant FFLs, with a sensitivity of 85.9% and specificity of 76.7%. The AUCs of R2* were not significantly different between the 2D-ROI and VOI methods.

CONCLUSION

R2* derived from multi-echo Dixon imaging whether by 2D-ROI or VOI can aid in differentiation between benign and malignant FLLs.

Performance of initial LI-RADS 2018 treatment response in predicting survival of patients with hepatocellular carcinoma following TACE: a retrospective, single-center cohort study

Purpose

Treatment response following transarterial chemoembolization (TACE) is frequently evaluated with Liver Imaging Reporting and Data System Treatment Response (LR-TR) algorithm, but its association with patients’ outcomes is not supported in the literature. The purpose of this study was to provide such data.

Methods

A retrospective analysis of 99 TACE patients with stage A/B hepatocellular carcinoma according to Barcelona-Clinic Liver Cancer staging system was performed. Two radiologists assessed LR-TR, while a third radiologist re-assessed divergent results. Overall survival (OS) and time to disease progression (TTP) were the primary endpoints of the study, while the Cox proportional hazard model was used for outcome analyses.

Results

Interobserver agreement was substantial between the two readers with κ = 0.69 (95% CI 0.58–0.81). The median OS in viable, equivocal, and non-viable groups were 27, 27, and 73 months, respectively (p < 0.001). However, after adjustment for confounding factors, there was no significant association between initial viable response and OS (HR 0.98 [95% CI 0.37–2.63], p = 0.97), while equivocal response remained statistically significant (HR 3.52. [95% CI 1.27–9.71], p = 0.015). No significant association was noted when viable and equivocal groups were analyzed in aggregate (HR 1.03 [95% CI 0.4–2.4], p = 0.96). The median TTP did not differ between non-viable and viable groups (23 vs 18 months, respectively; p = 0.98). None of the analyzed predictors was associated with TTP.

Conclusion

Initial LR-TR response was not an independent predictor for OS nor TTP. The preliminary results suggest the necessity for more aggressive management of equivocal patients.

Three-Dimensional Radiological Assessment of Ablative Margins in Hepatocellular Carcinoma: Pilot Study of Overlay Fused CT/MRI Imaging with Automatic Registration

BACKGROUND

We investigate the feasibility of image fusion application for ablative margin assessment in radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) and possible causes for a wrong initial evaluation of technical success through a side-by-side comparison.

METHODS

A total of 467 patients with 1100 HCCs who underwent RFA were reviewed retrospectively. Seventeen patients developed local tumor progressions (LTPs) (median size, 1.0 cm) despite initial judgments of successful ablation referring to contrast-enhanced images obtained in the 24 h after ablation. The ablative margins were reevaluated radiologically by overlaying fused images pre- and post-ablation.

RESULTS

The initial categorizations of the 17 LTPs had been grade A (absolutely curative) (n = 5) and grade B (relatively curative) (n = 12); however, the reevaluation altered the response categories to eight grade C (margin-zero ablation) and nine grade D (existence of residual HCC). LTP occurred in eight patients re-graded as C within 4 to 30.3 months (median, 14.3) and in nine patients re-graded as D within 2.4 to 6.7 months (median, 4.2) (p = 0.006). Periablational hyperemia enhancements concealed all nine HCCs reevaluated as grade D.

CONCLUSION

Side-by-side comparisons carry a risk of misleading diagnoses for LTP of HCC. Overlay fused imaging technology can be used to evaluate HCC ablative margin with high accuracy.

LI-RADS v2018 major criteria: Do hepatocellular carcinomas in non-alcoholic steatohepatitis differ from those in virus-induced chronic liver disease on MRI?

PURPOSE

LI-RADS v2018 diagnostic system is used to diagnose hepatocellular carcinoma (HCC) in at risk patients. However, its applicability to HCC in non-alcoholic steatohepatitis (NASH) has not been specifically studied. The purpose of this study was to assess the applicability of LI-RADS v2018 diagnostic system for HCC in patients with NASH.

MATERIALS AND METHODS

The MRI examinations of 41 patients with HCC and NASH (NASH group) were reviewed and compared to those obtained in 41 patients with HCC and virus-induced chronic liver disease (Virus group). MRI examinations of the two groups were compared for imaging presentation, LI-RADS major criteria and LI-RADS categorization. Qualitative variables were compared using Fisher exact test and quantitative variables using Mann-Whitney U test Interreader agreement was assessed using kappa statistic.

RESULTS

No significant differences in qualitative and quantitative variables were observed between the two groups. Most common findings in the two groups were hyperenhancement during the arterial phase and visibility on T2-weighted images (93 % vs. 98 %, P = 0.616 and 85 % vs. 88 %, P = 1.000 for NASH group and Virus group, respectively). No differences in prevalence between the two groups were found for any major LI-RADS v2018 criterion. Interreader agreement for LI-RADS categorization was strong for the NASH group (kappa = 0.802) and moderate for the virus group (kappa = 0.720). No differences were found between the two groups for LI-RADS categories (P =  0.303).

CONCLUSIONS

The LI-RADS v2018 diagnostic algorithm can be applied in patients with NASH.

MRI LI-RADS Version 2018: Impact of and Reduction in Ancillary Features

OBJECTIVE. The purpose of this study is to determine the impact of LI-RADS ancillary features on MRI and to ascertain whether the number of ancillary features can be reduced without compromising LI-RADS accuracy. MATERIALS AND METHODS. A total of 222 liver observations in 81 consecutive patients were identified on MRI between August 2013 and December 2018. The presence or absence of major and ancillary features was used to determine the LI-RADS category for LR-1 to LR-5 observations. Final diagnosis was established on the basis of pathologic findings or one of several composite clinical reference standards. Diagnostic accuracy was compared with and without ancillary features by use of the z test of proportions. Decision tree analysis and machine learning-based feature pruning were used to identify noncontributory ancillary features for LI-RADS categorization. Interobserver agreement with and without ancillary features was measured using the Krippendorff alpha coefficient, and comparisons were made using bootstrapping. A p < .05 was considered statistically significant. RESULTS. Application of ancillary features resulted in a change in the LI-RADS category of seven hepatocellular carcinomas (HCCs), with the category of six of seven (86%) HCCs upgraded; 51 benign observations also had a change in LI-RADS category, with the category of 33 (65%) of these observations downgraded. When ancillary features were applied, the percentage of HCCs in each LI-RADS category did not differ significantly compared with major features alone (p = .06-.49). Decision tree analysis and the machine learning model identified five ancillary features as noncontributory: corona enhancement, nodule-in-nodule, mosaic architecture, blood products in mass, and fat in a mass, more than in adjacent liver. Interobserver agreement was high with and without application of ancillary features; however, it was significantly higher without ancillary features (p < .001). CONCLUSION. Although ancillary features are an important component of LI-RADS, their impact may be small. Several ancillary features likely can be removed from LI-RADS without compromising diagnostic performance.

Intraindividual Comparison of Hepatocellular Carcinoma Washout between MRIs with Hepatobiliary and Extracellular Contrast Agents

Objective

To intraindividually compare hepatocellular carcinoma (HCC) washout between MRIs using hepatobiliary agent (HBA) and extracellular agent (ECA).

Materials and Methods

This study included 114 prospectively enrolled patients with chronic liver disease (mean age, 55 ± 9 years; 94 men) who underwent both HBA-MRI and ECA-MRI before surgical resection for HCC between November 2016 and May 2019. For 114 HCCs, the lesion-to-liver visual signal intensity ratio (SIR) using a 5-point scale (−2 to +2) was evaluated in each phase. Washout was defined as negative visual SIR with temporal reduction of visual SIR from the arterial phase. Illusional washout (IW) was defined as a visual SIR of 0 with an enhancing capsule. The frequency of washout and MRI sensitivity for HCC using LR-5 or its modifications were compared between HBA-MRI and ECA-MRI. Subgroup analysis was performed according to lesion size (< 20 mm or ≥ 20 mm).

Results

The frequency of portal venous phase (PP) washout with HBA-MRI was comparable to that of delayed phase (DP) washout with ECA-MRI (77.2% [88/114] vs. 68.4% [78/114]; p = 0.134). The frequencies were also comparable when IW was allowed (79.8% [91/114] for HBA-MRI vs. 81.6% [93/114] for ECA-MRI; p = 0.845). The sensitivities for HCC of LR-5 (using PP or DP washout) were comparable between HBA-MRI and ECA-MRI (78.1% [89/114] vs. 73.7% [84/114]; p = 0.458). In HCCs < 20 mm, the sensitivity of LR-5 was higher on HBA-MRI than on ECA-MRI (70.8% [34/48] vs. 50.0% [24/48]; p = 0.034). The sensitivity was similar to each other if IW was added to LR-5 (72.9% [35/48] for HBA-MRI vs. 70.8% [34/48] for ECA-MRI; p > 0.999).

Conclusion

Extracellular phase washout for HCC diagnosis was comparable between MRIs with both contrast agents, except for tumors < 20 mm. Adding IW could improve the sensitivity for HCC on ECA-MRI in tumors < 20 mm.

Effectiveness of intraprocedural dual-phase cone-beam computed tomography in detecting hepatocellular carcinoma and improving treatment outcomes following conventional transarterial chemoembolization

To investigate the effectiveness of intraprocedural dual-phase cone-beam computed tomography (CBCT) in detecting hepatocellular carcinoma (HCC) during conventional transcatheter arterial chemoembolization (TACE) and its effect on improving treatment outcomes. Between November 2018 and November 2019, data from 111 patients with unresectable HCCs (N = 263 lesions) were reviewed retrospectively. All patients had undergone baseline magnetic resonance imaging (MRI) scans within one month prior to the procedure. Both arterial-phase (AP) and delayed-phase CBCT images were acquired during all conventional TACEs. Each HCC detection rate when read by AP-CBCT and when read by dual-phase (DP) CBCT including both AP and delayed phase was compared with that of MRI, and the diagnosis of HCC was based on MRI. Additionally, the follow-up results concerning lipiodol uptake status and tumor response of the lesions detected only by AP-/DP-CBCT were analyzed and compared with MRI-only detected lesions. The overall sensitivity of DP-CBCT (94.7%) was significantly higher than that of AP-CBCT (89.0%) (p = 0.003). In particular, the rate of subcentimeter HCC detection by DP-CBCT was pronounced (91.5% vs. 80.3%) (p = 0.01). Lesions found only by DP-CBCT exhibited positive lipiodol uptake (n = 31/31; 100%) and showed complete or partial responses (n = 24/31; 77.4%) on follow-up CT imaging, while MRI-only detected lesions had less lipiodol uptake (n = 6/14, 42.9%) and complete or partial responses (n = 4/14; 28.6%) (p ≤ 0.001). DP-CBCT imaging during TACE enabled better detection of HCCs than when using AP-CBCT alone, and AP- and DP-CBCT is superior to MRI in detecting chemoembolization-sensitive lesions. This resulted in increased detectability of HCCs and the achievement of better treatment outcomes.

Comparison of LI-RADS with other non-invasive liver MRI criteria and radiological opinion for diagnosing hepatocellular carcinoma in cirrhotic livers using gadoxetic acid with histopathological explant correlation

AIM

To establish the diagnostic accuracy of the Liver Imaging Reporting and Data System (LI-RADS) for hepatocellular carcinoma (HCC) and compare its performance to that of international criteria from European Assofor the Study of the Liver (EASL), Japan Society of Hepatology (JSH), Asian Pacific Association for the Study of the Liver (APASL), and Organ Procurement and Transplantation Network (OPTN), and to the reporting radiologist's overall opinion regarding the probability of a nodule being a HCC by correlating with a histological diagnosis from whole liver explants.

MATERIALS AND METHODS

The present single-centre, retrospective review selected participants based on the following criteria: adults (≥18 years) listed for liver transplantation in 2014/2015, with liver cirrhosis at the time of magnetic resonance imaging (MRI) with hepatocyte specific contrast agent, and at least one liver lesion ≥10 mm on MRI with histology from subsequent liver explant for comparison. Each lesion was assessed against international criteria and given a "radiologist opinion" score of 1-5 (1 = definitely benign, 5 = definitely HCC).

RESULTS

Total 268 patient records were reviewed, with 105 eligible lesions identified from 47 patients. Median lesion size was 15.5 mm (range 10-68 mm). Sensitivity (%), specificity (%), and positive predictive value (PPV; %) for LI-RADS LR5 was 45, 89, and 89, for LI-RADS LR4+5 + TIV was 61, 80, and 86, for EASL was 44, 86 and 86, for JSH/APASL was 64, 81, and 87, for OPTN was 36, 90, and 88, and for "radiologist impression" of probably or definitely HCC was 79, 79, and 88 respectively.

CONCLUSIONS

MRI has moderate sensitivity and good specificity for the diagnosis of HCC with considerable variation depending on criteria used. OPTN criteria have the best specificity, but low sensitivity. "Radiologist opinion" gives highest overall accuracy with increases in sensitivity and reduction in specificity when compared to the imaging criteria.

A Pre-TACE Radiomics Model to Predict HCC Progression and Recurrence in Liver Transplantation. A Pilot Study on a Novel Biomarker

BACKGROUND

Despite Trans-Arterial Chemo Embolization (TACE) for hepatocellular carcinoma (HCC), a significant number of patients will develop progression on the liver transplant (LT) waiting list or disease recurrence post-LT. We sought to evaluate the feasibility of a pre-TACE radiomic model, an imaging-based tool to predict these adverse outcomes.

METHODS

We analyzed the pre-TACE computed tomography images of patients waiting for a LT. The primary endpoint was a combined event that included waitlist dropout for tumor progression or tumor recurrence post-LT. The radiomic features were extracted from the largest HCC volume from the arterial and portal venous phase. A third set of features was created, combining the features from these 2 contrast phases. We applied a LASSO feature selection method and a support vector machine classifier. Three prognostic models were built using each feature set. The models' performance was compared using 5-fold cross-validated Area Under the Receiver Operating Characteristic curves (AUC).

RESULTS

88 patients were included, of whom 33 experienced the combined event (37.5%). The median time to dropout was 5.6 months (IQR:3.6-9.3), and the median time for post-LT recurrence was 19.2 months (IQR:6.1-34.0). Twenty-four patients (27.3%) dropped out, and 64 (72.7%) patients were transplanted. Of these, 14 (21.9%) had recurrence post-LT. Model performance yielded a mean AUC of 0.70(±0.07), 0.87(±0.06) and 0.81(±0.06) for the arterial, venous and the combined models, respectively.

CONCLUSION

A pre-TACE radiomics model for HCC patients undergoing LT may be a useful tool for outcome prediction. Further external model validation with a larger sample size is required.

Hepatobiliary phase hypointensity on gadobenate dimeglumine-enhanced magnetic resonance imaging may improve the diagnosis of hepatocellular carcinoma

Background

To determine the clinical value of hepatobiliary phase (HBP) hypointensity for noninvasive diagnosis of hepatocellular carcinoma (HCC).

Methods

A total of 246 high-risk patients with 263 selected nodules (126 HCCs, 137 non-HCCs) undergoing gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) were included in the study. Imaging-based diagnoses of small (≤3 cm) and large (>3 cm) HCCs were made using the following 4 criteria: (I) non-rim arterial phase hyper-enhancement (APHE) plus hypointensity on the portal venous phase (PVP); (II) non-rim APHE plus hypointensity on the PVP and/or transitional phase (TP); (III) non-rim APHE plus hypointensity on the PVP and/or TP and/or HBP; (IV) criterion 3 plus non-LR-1/2/M. Based on typical imaging features, LR-1, LR-2, or LR-M (if definitely benign, probably benign, malignant but not HCC specific, respectively) were defined according to the Liver Imaging Reporting and Data System (LI-RADS). Sensitivities and specificities of imaging criteria were calculated and compared using McNemar’s test.

Results

Among the diagnostic criteria for small HCCs, criterion 3 and 4, which included HBP hypointensity, showed significantly higher sensitivities (96.4% and 94.6%, respectively) than criterion 1 (58.9%, P<0.001 for both). Moreover, criterion 4, which included HBP hypointensity and ancillary features, showed significantly higher specificity (94.7%) than criterion 3 (66.7%, P<0.001) and comparable specificity to criterion 1 (97.4%, P=0.375), achieving the highest accuracies (94.7%). The diagnostic performance of criterion 4 for large HCCs was similar to that for small HCCs.

Conclusions

HBP hypointensity acquired from Gd-BOPTA-MRI can improve sensitivity and maintain high specificity in the diagnosis of both small and large HCCs after excluding benignities or non-HCC malignancies according to characteristic imaging features.

Role of Locoregional Therapies in Patients With Hepatocellular Cancer Awaiting Liver Transplantation

Hepatocellular cancer (HCC) is the fifth most common cancer in the world and the third most common cause of cancer-related deaths. The United Network for Organ Sharing has its own staging criteria for organ allocation, which is a modification of tumor-node-metastasis staging of American Joint Committee on Cancer. For the purpose of clarity, United Network for Organ Sharing staging will be described as uT1, uT2 (Milan criteria), and uT3 (eligible for downstaging) in this review. For those with unresectable HCC or those with advanced liver disease and HCC but within the Milan criteria, liver transplantation is the treatment of choice. Because of prolonged waiting period on the liver transplant list in many parts of the world for deceased donor liver transplantation, there is a serious risk of dropout from the liver transplant list because of tumor progression. For those patients, locoregional therapies might need to be considered, and moreover, there is circumstantial evidence to suggest that tumor progression after locoregional therapies might be a surrogate marker of unfavorable tumor biology. There is no consensus on the role or type of locoregional therapies in the management of patients with uT1 and uT2 eligible for liver transplant and of those with lesions larger than uT2 but eligible for downstaging protocol (uT3 lesions). In this review, we examine the role of locoregional therapies in these patients stratified by staging and propose treatment options based on the current evidence of tumor progression rates while awaiting liver transplantation and tumor recurrence rates after liver transplantation.

Imaging of hepatocellular carcinoma: a pilot international survey

PURPOSE

To perform an international survey on current practices in imaging-based surveillance, diagnosis, staging, and assessment of treatment response for HCC.

MATERIALS AND METHODS

Three themes were covered in this international survey: demographics of respondents and liver imaging expertise; imaging practices for screening, surveillance, diagnosis, staging, and assessment of treatment response for HCC; and diagnostic imaging systems used. Descriptive summaries were created.

RESULTS

Of 151 respondents, 22.5% were from Asia, 6.0% from Europe, 19.9% from North America, 26.5% from South America, and 25.2% from Australasia; 57.0% respondents worked in academic and 34.4% in private or mixed settings. Non-contrast ultrasound was most commonly used for screening and surveillance of HCC (90.7%), and multiphase computed tomography was used for diagnosis (96.0%). Extracellular contrast agents (69.5%) were the most commonly used MRI contrast agents and Lumason/SonoVue (31.1%) is the most commonly used contrast-enhanced ultrasound contrast agent. A majority (94.0%) of respondents use ancillary imaging features for assessment of liver lesions in at-risk patients. Usage of diagnostic imaging systems for HCC varied by region. RECIST or mRECIST criteria were most commonly used for assessing HCC treatment response (48.3%). Most respondents agreed that a standardized classification for the diagnosis of HCC is needed (68.9%) and that an atlas and lexicon would help improve inter-reader agreement (71.5%).

CONCLUSION

Practices and recommendations for imaging of HCC vary between geographical regions. Future efforts to develop a unified system should address regional differences and potential barriers for adoption of a standardized diagnostic system for HCC.

Virtual unenhanced imaging of the liver derived from 160-mm rapid-switching dual-energy CT (rsDECT): Comparison of the accuracy of attenuation values and solid liver lesion conspicuity with native unenhanced images

OBJECTIVES

To evaluate the reliability of attenuation values of the liver parenchyma and focal liver lesions on virtual unenhanced images from arterial (VUEart) and portal venous phases (VUEport) compared to native unenhanced (NU) attenuation values in patients referred for assessment of malignant liver lesions.

METHODS

Seventy-three patients with confirmed primary or metastatic liver tumors who underwent a multiphase contrast-enhanced rapid-switching kVp dual-energy CT (rsDECT) were included in this IRB-approved retrospective study. Both qualitative and quantitative analyses - including the lesion-to-liver contrast-to-noise ratio (LL-CNR) - were performed and compared between NU and both VUEart and VUEport images.

RESULTS

The mean liver attenuation values were significantly lower in VUEart images (56.7 ± 6.7 HU) than in NU images (59.6 ± 7.5 HU, p = 0.008), and were comparable between VUEart and VUEport images (57.9 ± 6 UH, p = 0.38) and between VUEport and NU images (p = 0.051). The mean liver lesions attenuation values were comparable between NU, VUEart and VUEport images (p = 0.60). Strong and significant correlations values were found both in liver lesions and tumor-free parenchyma (r = 0.82-0.91, p < 0.01). The mean LL-CNR was significantly higher in VUEart and VUEport images than in NU images (1.7 ± 1 and 1.6 ± 1.1 vs 0.9 ± 0.6; p < 0.001), but was comparable between VUEart and VUEport images (p > 0.9). Lesion conspicuity was significantly higher in VUEport images than in NU images (p < 0.001).

CONCLUSION

VUEport images derived from 3rd generation rsDECT could confidently replace NU images in patients undergoing assessment for malignant liver lesions. These images provide comparable attenuation values in both liver lesions and liver parenchyma while reducing the radiation dose and scanning time.

Vanishing washout of hepatocellular carcinoma according to the presence of hepatic steatosis: diagnostic performance of CT and MRI

OBJECTIVES

To compare the presence of washout and the diagnostic performance of computed tomography (CT) and magnetic resonance imaging (MRI) for hepatocellular carcinoma (HCC) according to the presence of hepatic steatosis.

METHODS

This retrospective study included 566 patients with chronic liver disease who had undergone hepatic resection for hepatic tumors (482 HCCs and 84 non-HCCs) between January 2016 and June 2018 and had available multiphasic CT and MR images. Patients were allocated in the fatty liver (n = 141) or non-fatty liver (n = 425) group according to the presence of hepatic steatosis, defined as lipid droplets in at least 5% of hepatocytes on pathological examination. The presence of HCC washout and the diagnostic performance of CT and MRI for HCC were compared between the groups.

RESULTS

HCC washout was less frequently seen in the fatty liver group than in the non-fatty liver group on CT (61.5% vs. 88.9%, p < 0.001), whereas it was similarly present on MRI in both groups (77.0% vs. 74.4%, p = 0.565). For diagnosis of HCC, the sensitivity (53.3% vs. 80.0%, p < 0.001) and accuracy (53.9% vs. 80.9%, p < 0.001) of CT were lower in the fatty liver group than in the non-fatty liver group. However, for MRI, these values were not significantly different between the groups (p > 0.05).

CONCLUSIONS

Hepatic steatosis significantly decreased the performance of CT for the diagnosis of HCC, whereas it did not significantly alter the performance of MRI.

KEY POINTS

• Unlike MRI, there is vanishing HCC washout on CT caused by the background hepatic steatosis. • The diagnostic performance of CT for the diagnosis of HCC was significantly altered by hepatic steatosis. • The optimal cutoff HU value of the liver parenchyma for the vanishing washout of HCC was < 50 HU on unenhanced CT images.

Unusual Primary Neoplasms of the Adult Liver: Review of Imaging Appearances and Differential Diagnosis

The radiological appearance of common primary hepatic tumors such as hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) is widely recognized. Hepatic masses with unusual histology are occasionally encountered, but seldom suspected on imaging. However, many possess characteristic imaging findings, which when assessed along with the clinical and demographic background and serum tumor markers, may enable a prospective diagnosis. This review attempts to familiarize the reader with the clinicopathological characteristics, imaging manifestations, and differential diagnosis of these unusual liver tumors in adults. Biphenotypic primary liver carcinoma is suspected in masses showing distinct areas of HCC and CCA-type enhancement pattern in cirrhotic livers. Fibrolamellar carcinoma occurs in young individuals without underlying chronic liver disease and shows a characteristic T2-hypointense scar frequently showing calcification. Perivascular epithelioid cell tumors are differentials for any arterial hyperenhancing mass in the noncirrhotic liver, particularly in patients with tuberous sclerosis. Multifocal subcapsular tumors showing target-like morphology, capsular retraction and "lollipop" sign are suspicious for epithelioid hemangioendothelioma. On the other hand, multiple hemorrhagic lesions showing patchy areas of bizarre-shaped arterial phase hyperenhancement are suspicious for angiosarcoma. Primary hepatic lymphoma (PHL) is suspected when patients with immunosuppression present with solitary or multifocal masses that insinuate around vessels and bile ducts without causing luminal narrowing. Intense diffusion restriction and low-level homogeneous or target-like enhancement are also ancillary features of PHL. Primary hepatic neuroendocrine tumor shows uptake on Ga-68 DOTANOC PET/CT. Although a straightforward diagnosis may be difficult in these cases, awareness of the characteristic imaging appearances is helpful in suspecting the diagnosis.

Diagnostic performance of the LR-M criteria and spectrum of LI-RADS imaging features among primary hepatic carcinomas

PURPOSE

To evaluate the diagnostic performance of LR-M criteria for differentiating hepatocellular carcinoma, intrahepatic mass-forming cholangiocarcinoma, and combined hepatocellular-cholangiocarcinoma and to compare the imaging features of each type.

METHODS

In this retrospective study, 110 patients were surgically diagnosed with cholangiocarcinoma (n = 67) and combined hepatocellular-cholangiocarcinoma (n = 43) at a single tertiary hospital between 2013 and 2018. Among them, those with risk factors were enrolled (16 cholangiocarcinomas and 33 combined hepatocellular-cholangiocarcinomas). Forty-nine other patients with size-matched hepatocellular carcinoma were selected as a control group. Two independent readers evaluated the imaging findings of the preoperative MRIs based on LI-RADS version 2018 and assigned an LI-RADS category. The diagnostic performance of the LR-M criteria for diagnosing cholangiocarcinoma or combined hepatocellular-cholangiocarcinoma was evaluated, and the imaging features were compared. The imaging findings of the tumors in patients without risk factors (51 cholangiocarcinomas and 10 combined hepatocellular-cholangiocarcinomas) were evaluated for subgroup analysis.

RESULTS

In the non-hepatocellular carcinoma group, 33 patients were categorized into LR-M and 14 patients into LR-5 (67.3% and 28.6%, respectively), while 5 patients with hepatocellular carcinoma were categorized into LR-M and 38 patients into LR-5 (10.2% and 77.6%, respectively). Sensitivity and specificity of the LR-M criteria were 67.3% and 89.8%, respectively. When more than two LR-M features were present, cholangiocarcinoma or combined hepatocellular-cholangiocarcinoma were suggested with a specificity of 95.9%.

CONCLUSION

The diagnostic performance of the LR-M criteria is acceptable with moderate sensitivity and high specificity for both cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma. Imaging findings of primary hepatic carcinomas should be understood as a spectrum.

Hepatocellular Carcinoma Demonstrates Heterogeneous Growth Patterns in a Multicenter Cohort of Patients With Cirrhosis

BACKGROUND AND AIMS

There are limited data on hepatocellular carcinoma (HCC) growth patterns, particularly in Western cohorts, despite implications for surveillance, prognosis, and treatment. Our study's aim was to quantify tumor doubling time (TDT) and identify correlates associated with indolent and rapid growth.

APPROACH AND RESULTS

We performed a retrospective multicenter cohort study of patients with cirrhosis diagnosed with HCC from 2008 to 2017 at six US and European health systems with two or more contrast-enhanced imaging studies performed ≥ 30 days apart prior to HCC treatment. Radiologists independently measured tumors in three dimensions to calculate TDT and specific growth rate (SGR). We used multivariable ordinal logistic regression to identify factors associated with indolent (TDT > 365 days) and rapid (TDT < 90 days) tumor growth. In the primary cohort (n = 242 patients from four centers), median TDT was 229 days (interquartile range [IQR], 89-627) and median SGR was 0.3% per day (IQR, 0.1%-0.8%). Over one-third (38%) of HCCs had indolent growth, 36.8% intermediate growth, and 25.2% rapid growth. In multivariable analysis, indolent growth was associated with larger tumor diameter (odds ratio [OR], 1.15, 95% confidence interval [CI], 1.03-1.30) and alpha-fetoprotein < 20 ng/mL (OR, 1.90; 95% CI, 1.12-3.21). Indolent growth was more common in nonviral than viral cirrhosis (50.9% versus 32.1%), particularly in patients with T1 HCC (OR, 3.41; 95% CI, 1.08-10.80). Median TDT (169 days; IQR 74-408 days) and SGR (0.4% per day) were similar in an independent cohort (n = 176 patients from two centers).

CONCLUSIONS

In a large Western cohort of patients with HCC, we found heterogeneous tumor growth patterns, with one-fourth exhibiting rapid growth and over one-third having indolent growth. Better understanding different tumor growth patterns may facilitate a precision approach to prognostication and treatment.

LI-RADS 4 or 5 categorization may not be clinically relevant for decision-making processes: A prospective cohort study

INTRODUCTION AND OBJECTIVES

The liver imaging reporting data system (LI-RADS) for hepatocellular carcinoma (HCC) was proposed to standardize and enhance consensus of reporting. However, clinical utility of LI-RADS has not been evaluated in Latin America. We therefore sought to compare LI-RADS categories with histopathology findings in liver transplant (LT) explants in a regional center.

MATERIALS AND METHODS

Prospective cohort study conducted between 2012 and 2018 in a single center from Argentina including patients with HCC listed for LT. LI-RADS definitions were applied to magnetic resonance images (MRI) or computed tomography (CT) abdominal scans at time of listing and at final pre-LT reassessment and compared to explant pathology findings; specifically, major nodule (NOD1).

RESULTS

Of 130 patients with HCC listed for LT (96.1% with cirrhosis and 35.6% with hepatitis C virus infection), 72 underwent LT. Overall, 65% had imaging HCC diagnosis based on MRI (n = 84), 26% with CT (n = 34) and 9% (n = 12) with both methods. Among LT patients with pre-transplant imaging at our institution (n = 42/72), 69% of the NOD1 were LR-5, 21% LR-4 and 10% LR-3. Definite HCC diagnosis was 50% in LR-3 NOD1 (CI 18-90); none presented microvascular invasion. In LR-4 NOD1, HCC was confirmed in 89% (CI 59-98), of which 11% showed microvascular invasion; whereas in LR-5 NOD1 77% (CI 64-87) had confirmed HCC, 17% with microvascular invasion.

CONCLUSIONS

LI-RADS was useful to standardize reports; however, no significant differences were observed between LR-4 and LR-5 HCC probability when compared to explant pathology.

Predictive factors of truncation artifacts in the arterial phase of Gd-EOB-DTPA-enhanced MRI: a nationwide multicenter study

PURPOSE

To identify predictive factors for truncation artifacts (TAs) in the arterial phase of Gd-EOB-DTPA-enhanced MRI in a multicenter study in Japan.

MATERIALS AND METHODS

Data on patient factors (age, sex, weight, presence of viral hepatitis, and other conditions) and imaging parameters (e.g., triggering, voxel size, matrix, k-space ordering, acquisition time, reduction factor, flip angle, fat suppression, field strength, injection rate, and saline volume) were obtained. Univariate and multivariate analyses were performed to investigate the correlation of these parameters.

RESULTS

We evaluated 1444 patients from 43 institutions who were scanned using GE, Siemens, Philips, or Toshiba MRI equipment (501, 354, 349, and 240 patients, respectively). The total incidence of TAs was 12.5% (17.2, 3.6, 15.7, and 12.1%, respectively). The matrix [odds ratio (OR) 0.13], flip angle (OR 5.77), use of fat suppression (OR 0.106), and field strength (OR 0.092) used in the Philips equipment significantly increased the incidence of TAs in MRI examination.

CONCLUSIONS

The incidence of TAs in the arterial phase is influenced by several patient factors and imaging parameters. Especially, Siemens and Toshiba equipment had a significantly lower frequency of TAs. This indicates that such vendor-specific technology used in the dynamic sequence may have a TA-resistant effect.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Guidelines and Good Clinical Practice Recommendations for Contrast-Enhanced Ultrasound (CEUS) in the Liver-Update 2020 WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

A meta-analysis of the added value of diffusion weighted imaging in combination with contrast-enhanced magnetic resonance imaging for the diagnosis of small hepatocellular carcinoma lesser or equal to 2 cm

Diffusion weighted imaging (DWI) has been found to increase the sensitivity in the diagnosis of small hepatocellular carcinoma (HCC), although additional studies are required to confirm its value. The aim of the present study was to explore the diagnostic performance of DWI combined with contrast-enhanced magnetic resonance imaging (MRI) for small HCC by performing a meta-analysis. Literature databases (PubMed, Embase, Web of Science and Cochrane Library databases) were searched to identify studies reporting the sensitivity and specificity of MRI with DWI for the diagnosis of small HCCs. Pooled sensitivity and specificity were generated using a bivariate random effect model. Multilevel mixed-effects logistic regression analysis was used to examine the value of DWI combined with conventional MRI. A total of 837 small HCCs and 545 benign liver lesions from 10 studies were included. The overall sensitivity and specificity of DWI combined with contrast-enhanced MRI was 0.88 (95% CI, 0.80-0.93) and 0.90 (95% CI, 0.81-0.95), respectively. Compared with that in contrast-enhanced MRI, DWI with contrast-enhanced MRI had a significantly higher sensitivity for the diagnosis of small HCC (P=0.01) while there was no significant difference in the specificity (P=0.603). The present meta-analysis suggests that DWI combined with contrast-enhanced MRI may increase the sensitivity, whilst maintaining high specificity for the diagnosis of small HCCs with a diameter ≤2 cm.

Argentinian clinical practice guideline for surveillance, diagnosis, staging and treatment of hepatocellular carcinoma

The A.A.E.E.H has developed this guideline for the best care of patients with hepatocellular carcinoma (HCC) from Argentina. It was done from May 2018 to March 2020. Specific clinical research questions were systematically searched. The quality of evidence and level of recommendations were organized according to GRADE. HCC surveillance is strongly recommended with abdominal ultrasound (US) every six months in the population at risk for HCC (cirrhosis, hepatitis B or hepatitis C); it is suggested to add alpha-feto protein (AFP) levels in case of inexeperienced sonographers. Imaging diagnosis in patients at risk for HCC has high specificity and tumor biopsy is not mandatory. The Barcelona Clinic Liver Cancer algorithm is strongly recommended for HCC staging and treatment-decision processes. Liver resection is strongly recommended for patients without portal hypertension and preserved liver function. Composite models are suggested for liver transplant selection criteria. Therapies for HCC with robust clinical evidence include transarterial chemoembolization (TACE) and first to second line systemic treatment options (sorafenib, lenvatinib, regorafenib, cabozantinib and ramucirumab). Immunotherapy with nivolumab and pembrolizumab has failed to show statistical benefit but the novel combination of atezolizumab plus bevacizumab has recently shown survival benefit over sorafenib in frontline.

Gadoxetic acid-enhanced MRI for diagnosis of hepatocellular carcinoma in patients with chronic liver disease: can hypointensity on the late portal venous phase be used as an alternative to washout?

PURPOSE

To investigate the added value of considering hypointensity on late portal venous phase (LPVP) images as washout for diagnosis of hepatocellular carcinoma (HCC) using gadoxetic acid-enhanced MRI (Gd-EOB-MRI) in patients with chronic liver disease (CLD).

METHODS

This retrospective study comprised 97 patients at high risk for HCC who underwent Gd-EOB-MRI including unenhanced, multi-arterial phase, conventional portal venous phase (CPVP, 60 s), and LPVP (mean, 99.9 ± 9.1 s; range, 90-119 s) images. A total of 115 hepatic lesions were identified by histopathological or clinical diagnosis. Three independent radiologists assessed the MRI images by consensus. Diagnosis of HCC was made using criteria of arterial hyperenhancement and hypointensity relative to the surrounding liver parenchyma (1) on CPVP or (2) on CPVP and/or LPVP images. The generalized estimating equation was used to compare diagnostic performance for HCC between Criterion 1 and 2.

RESULTS

In 82 HCCs, the frequency of hypointensity differed significantly between the CPVP and LPVP images (64.6% [53/82] vs. 84.1% [69/82], P < 0.001). Among 33 non-HCCs, two cHCC-CCs showed additional hypointensity on LPVP than CPVP images (33.3% [11/33] vs. 39.4% [13/33], P = 0.500). Criterion 2 provided significantly greater sensitivity for diagnosing HCC than Criterion 1 (54.9% [45/82] vs. 74.4% [61/82], P < 0.001), with relatively little reduction in specificity (90.9% [30/33] vs. 84.8% [28/33], P = 0.145).

CONCLUSION

Additional use of LPVP hypointensity as washout could significantly improve sensitivity for HCC diagnosis when utilizing Gd-EOB-MRI in patients with CLD, without a significant decrease in specificity.

Role of imaging in management of hepatocellular carcinoma: surveillance, diagnosis, and treatment response

Imaging plays a notable role in hepatocellular carcinoma (HCC) surveillance, diagnosis, and treatment response assessment. Whereas HCC surveillance among at-risk patients, including those with cirrhosis, has traditionally been ultrasound-based, there are increasing data showing that this strategy is operator-dependent and has insufficient sensitivity when used alone. Several novel blood-based and imaging modalities are currently being evaluated to increase sensitivity for early HCC detection. Multi-phase computed tomography (CT) or contrast-enhanced magnetic resonance imaging (MRI) should be performed in patients with positive surveillance tests to confirm a diagnosis of HCC and perform cancer staging, as needed. HCC is a unique cancer in that most cases can be diagnosed radiographically without histological confirmation when demonstrating characteristic features such as arterial phase hyperenhancement and delayed phase washout. The Liver Imaging Reporting and Data System offers a standardized nomenclature for reporting CT or MRI liver findings among at-risk patients. Finally, cross-sectional imaging plays a critical role for assessing response to any HCC therapy as well as monitoring for HCC recurrence in those who achieve complete response.

Intra-individual comparison of dual portal venous phases for non-invasive diagnosis of hepatocellular carcinoma at gadoxetic acid-enhanced liver MRI

OBJECTIVES

To compare the diagnostic performances of first and second portal venous phases (PVP1 and PVP2) in revealing washout and capsule appearance for non-invasive HCC diagnoses in gadoxetic acid-enhanced MRI (Gd-EOB-MRI).

METHODS

This retrospective study included 123 at-risk patients with 160 hepatic observations (HCCs, n = 116; non-HCC malignancies, n = 18; benign, n = 26) showing arterial phase hyper-enhancement (APHE) ≥ 1 cm at Gd-EOB-MRI. The mean time intervals from gadoxetic acid injection to PVP1 and PVP2 acquisitions were 53 ± 2 s and 73 ± 3 s, respectively. After evaluating image findings independently, imaging findings and diagnoses were finalized by a consensus of two radiologists using either PVP1 or PVP2 image sets according to the LI-RADS v2018 or EASL criteria. Sensitivity, specificity, and accuracy were compared.

RESULTS

Among HCCs, more washout and enhancing capsule were observed in PVP2 (83.6% and 27.6%) than in PVP1 (50.9% and 19.8%) (p < 0.001, both). The PVP2 set presented significantly higher sensitivity (83.6% vs. 53.5%, LI-RADS; 82.8% vs. 50.0%, EASL; p < 0.001, both) and accuracy (0.88 vs. 0.73, LI-RADS; 0.88 vs. 0.72, EASL; p < 0.001, both) than the PVP1 set without significant specificity loss (93.2% vs. 93.2%, by LI-RADS or EASL; p = 0.32, both). None of the non-HCC malignancy was non-invasively diagnosed as HCC in both PVP image sets.

CONCLUSION

Late acquisition of PVP detected washout and enhancing capsule of HCC more sensitively than early acquisition, enabling accurate diagnoses of HCC, according to LI-RADS or EASL criteria.

KEY POINTS

• Among HCCs, more washout and enhancing capsules were observed in PVP2 than PVP1, quantitatively and qualitatively. • The portal venous phase acquired at around 70 s after contrast media administration (PVP2) provided significantly higher sensitivity and AUC value than PVP1 by using LI-RADS v2018 or EASL criteria. • More HCCs were categorized as LR-5 in PVP2 than in PVP1 images, and the specificity of PVP2 (93.5%) was comparable with PVP1 (93.5%).

Outcome of LR-3 and LR-4 observations without arterial phase hyperenhancement at Gd-EOB-DTPA-enhanced MRI follow-up

OBJECTIVE

The aim of this study was to retrospectively analyze the outcome of LR-3 and LR-4 without arterial phase hyperenhancement (APHE), and identify which features could predict LR-5 progression on serial Gd-EOB-DTPA-enhanced MRI follow-up.

METHODS

Forty-nine cirrhotic patients with 55 LR-3 and 19 LR-4 without APHE were evaluated. Observations were classified as decreased, stable or increased in category at follow-up. Observation size and LI-RADS major and ancillary features were evaluated.

RESULTS

Seventeen/fifty-five (31%) LR-3 and 8/19 (42%) LR-4 progressed to LR-5 at follow-up. Baseline LI-RADS major and ancillary features were not significantly different among LR-3 and LR-4. A diameter ≥ 10 mm significantly increased LR-5 progression risk of LR-3 (OR = 6.07; 95% CI: 0.12; 60.28]; P < .001). LR-4 with a diameter ≥ 10 mm more likely become LR-5 at follow-up (OR = 8.95; 95% CI: 0.73; 111.8; P = .083]).

CONCLUSION

LR-3 and LR-4 without APHE were often downgraded or remained stable in category on Gd-EOB-DTPA-enhanced MRI follow-up.

Between Always and Never: Evaluating Uncertainty in Radiology Reports Using Natural Language Processing

The ideal radiology report reduces diagnostic uncertainty, while avoiding ambiguity whenever possible. The purpose of this study was to characterize the use of uncertainty terms in radiology reports at a single institution and compare the use of these terms across imaging modalities, anatomic sections, patient characteristics, and radiologist characteristics. We hypothesized that there would be variability among radiologists and between subspecialities within radiology regarding the use of uncertainty terms and that the length of the impression of a report would be a predictor of use of uncertainty terms. Finally, we hypothesized that use of uncertainty terms would often be interpreted by human readers as "hedging." To test these hypotheses, we applied a natural language processing (NLP) algorithm to assess and count the number of uncertainty terms within radiology reports. An algorithm was created to detect usage of a published set of uncertainty terms. All 642,569 radiology report impressions from 171 reporting radiologists were collected from 2011 through 2015. For validation, two radiologists without knowledge of the software algorithm reviewed report impressions and were asked to determine whether the report was "uncertain" or "hedging." The relationship between the presence of 1 or more uncertainty terms and the human readers' assessment was compared. There were significant differences in the proportion of reports containing uncertainty terms across patient admission status and across anatomic imaging subsections. Reports with uncertainty were significantly longer than those without, although report length was not significantly different between subspecialities or modalities. There were no significant differences in rates of uncertainty when comparing the experience of the attending radiologist. When compared with reader 1 as a gold standard, accuracy was 0.91, sensitivity was 0.92, specificity was 0.9, and precision was 0.88, with an F1-score of 0.9. When compared with reader 2, accuracy was 0.84, sensitivity was 0.88, specificity was 0.82, and precision was 0.68, with an F1-score of 0.77. Substantial variability exists among radiologists and subspecialities regarding the use of uncertainty terms, and this variability cannot be explained by years of radiologist experience or differences in proportions of specific modalities. Furthermore, detection of uncertainty terms demonstrates good test characteristics for predicting human readers' assessment of uncertainty.

Hepatic enhancement in cirrhosis in the portal venous phase: what are the differences between gadoxetate disodium and gadobenate dimeglumine?

PURPOSE

To compare the level of parenchymal and portal venous enhancement in the portal venous phase (PVP) in cirrhotic patients undergoing gadoxetate disodium- and gadobenate dimeglumine-enhanced MRI.

METHODS

In this retrospective study, 84 cirrhotic patients (mean age ± SD: 66 ± 13 years) who underwent contrast-enhanced MRI with both gadoxetate disodium and gadobenate dimeglumine between 2012 and 2018 were included. Two readers measured signal intensities of hepatic parenchyma, portal vein and psoas muscle on precontrast and PVP. Relative enhancement (RE), image contrast, and portal vein-to-liver contrast difference were calculated. Intraindividual differences were compared with the Wilcoxon signed rank-sum test and inter-reader differences with the intraclass correlation coefficient (ICC).

RESULTS

In PVP, gadoxetate disodium provided lower RE than gadobenate dimeglumine (Reader 1: 42.4 ± 44.6 vs. 56.1 ± 58.8, p = 0.044; Reader 2: 42.4 ± 42.9 vs. 57.7 ± 60.5, p = 0.027;), lower image contrast (Reader 1: 0.27 ± 0.11 vs. 0.35 ± 0.11, respectively; p < 0.001; Reader 2: 0.29 ± 0.10 vs. 0.37 ± 0.07, respectively; p < 0.001), and lower portal vein-to-liver contrast difference (Reader 1: 0.89 ± 0.39 vs. 1.42 ± 0.90, p < 0.001; Reader 2: 0.95 ± 0.40 vs. 1.28 ± 0.37, p < 0.001). ICC was 0.94, 0.79, and 0.69 for RE, image contrast, and portal vein-to-liver contrast difference, respectively.

CONCLUSION

In cirrhotic patients, gadoxetate disodium yielded lower enhancement of the hepatic parenchyma and lower contrast of the portal vein than gadobenate dimeglumine in PVP.

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.

LI-RADS M (LR-M) criteria and reporting algorithm of v2018: diagnostic values in the assessment of primary liver cancers on gadoxetic acid-enhanced MRI

PURPOSE

To evaluate diagnostic values of the liver imaging reporting and data system (LI-RADS) M (LR-M) category based on novel explicit criteria that accept both targetoid and nontargetoid LR-M features and the suggested reporting algorithm of LI-RADS v2018 to assess primary liver cancers (PLCs) on gadoxetic acid-enhanced MRI (Gd-EOB-MRI).

METHODS

This retrospective study included 165 patients at high risk for hepatocellular carcinoma (HCC) with pathologically confirmed PLCs (HCC, n = 113; intrahepatic cholangiocarcinoma [iCCA], n = 23; and combined hepatocellular cholangiocarcinoma [cHCC-CCA], n = 29). Two radiologists independently analyzed Gd-EOB-MRI features and determined LI-RADS category for each tumor and categorized the likely etiology either as HCC or non-HCC malignancy if LR-M was assigned. Diagnostic performances for HCC or those for malignancy were compared according to imaging criteria.

RESULTS

LR-M was assigned in 95.7%/91.3% of iCCAs; 55.2%/58.6% of cHCC-CCAs; and 21.2%/17.7% of HCCs in reviewers 1/2. Combination of LR-5 plus LR-M resulted in sensitivity of 95.2%/97.6% to diagnose PLCs as malignant, which were significantly higher than that of LR-5 plus "LR-M with ≥ 1 targetoid appearances" (84.8%/91.5%, Ps < 0.01). In comparison to LR-5, LR-5 plus "LR-M of HCC as likely etiology" resulted in significant increase in sensitivity (73.5%/79.6% versus 87.6%/92.9%, Ps < 0.001) but significant decrease in specificity (76.9%/75.0% versus 57.7%/50.0%, P = 0.002 and < 0.001) in the diagnosis of HCC.

CONCLUSION

The LR-M criteria v2018 are useful to differentiate non-HCC malignancies from HCCs and to accurately diagnose PLCs as a malignancy. Reporting the likely etiology in LR-M may facilitate a more sensitive detection of HCC, but along with a considerable decrease in specificity.

2019 Chinese clinical guidelines for the management of hepatocellular carcinoma: updates and insights

Importance

Approximately half of newly-diagnosed hepatocellular carcinoma (HCC) cases in the world occur in China, with hepatitis B virus (HBV) infection being the predominant risk factor. Recently, the guidelines for the management of Chinese HCC patients were updated.

Objective

The past decade has witnessed a great improvement in the management of hepatocellular carcinoma (HCC). This study reviews the recommendations in the 2019 Chinese guidelines and makes comparison with the practices from the Western world.

Evidence Review

The updated recommendations on the surveillance, diagnosis, and treatment algorithm of HCC in the 2019 Chinese guidelines were summarized, and comparisons among the updated Chinese guidelines, the European Association for the Study of the Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) guidelines were made.

Findings

Besides imaging and pathological diagnoses, novel biomarkers like the seven-micro-RNA panel are advocated for early diagnoses and therapeutic efficacy evaluation in the updated Chinese guidelines. The China liver cancer (CNLC) staging system, proposed in the 2017 guidelines, continues to be the standard model for patient classification, with subsequent modifications and updates being made in treatment allocations. Compared to the Barcelona Clinic Liver Cancer (BCLC) system, the CNLC staging system employs resection, transplantation, and transarterial chemoembolization (TACE) for more progressed HCC. TACE in combination with other regional therapies like ablation or with systemic therapies like sorafenib are also encouraged in select patients in China. The systemic treatments for HCC have evolved considerably since lenvatinib, regorafenib, carbozantinib, ramucirumab and immune checkpoint inhibitors (ICIs)were first prescribed as first-line or second-line agents.

Conclusions and Relevances

Novel biomarkers, imaging and operative techniques are recommended in the updated Chinese guideline. More aggressive treatment modalities are suggested for more progressed HBV-related HCC in China.

Measuring and Teaching Confidence Calibration Among Radiologists: A Multi-Institution Study

OBJECTIVE

Our purpose was to assess the calibration of resident, fellow, and attending radiologists on a simple image classification task (presence or absence of an anterior cruciate ligament [ACL] tear based on interpretation of sagittal proton density, fat-saturated MR images) and to assess whether teaching residents could improve their calibration.

METHODS

We created a test containing 30 randomized, sagittal, proton density, fat-saturated MR images of the ACL (15 normal, 15 torn). This test was administered in person to 20 trainees and 3 attendings at one medical center in one state. An online version of the test was given to 23 trainees and 14 attendings from 11 other medical centers in nine other states. Subjects were asked to give their confidence level (0%-100%) that each ACL was torn.

RESULTS

Cross-sectional data were collected from 60 radiologists (mean time after medical school = 9.3 years, minimum = 1 year, maximum = 36 years). This demonstrated a statistically significant improvement in calibration as a function of increasing experience (P = .020). Longitudinal data were collected from 12 trainees at the start and end of their musculoskeletal radiology rotation, with an intervening review of the primary and secondary signs of ACL tear on MR. A statistically significant improvement in calibration was noted during the rotation (P = .028).

CONCLUSIONS

Confidence calibration is a promising tool for quality improvement and radiologist self-assessment. Our study showed that calibration loss improves with experience in radiologists tested on a common and clinically important image classification task. We also demonstrated that calibration can be successfully taught to residents over a relatively short period (2-4 weeks).

Virtual monoenergetic images preserve diagnostic assessability in contrast media reduced abdominal spectral detector CT

OBJECTIVES

To investigate if low-keV virtual monoenergetic images (VMI_40keV) from abdominal spectral detector CT (SDCT) with reduced intravenous contrast media application (RCM) provide abdominal assessment similar to conventional images with standard contrast media (SCM) dose.

METHODS

78 patients with abdominal SDCT were retrospectively included: 41 patients at risk for adverse reactions who received 44 RCM examinations with 50 ml and 37 patients who underwent 44 SCM examinations with 100 ml of contrast media (CM) and who were matched for effective body diameters. RCM, SCM images and RCM-VMI_40keV were reconstructed. Attenuation and signal-to-noise ratio (SNR) of liver, pancreas, kidneys, lymph nodes, psoas muscle, aorta and portal vein were assessed ROIs-based. Contrast-to-noise ratios (CNR) of lymph nodes vs aorta/portal vein were calculated. Two readers evaluated organ/vessel contrast, lymph node delineation, image noise and overall assessability using 4-point Likert scales.

RESULTS

RCM were inferior to SCM images in all quantitative/qualitative criteria. RCM-VMI_40keV and SCM images showed similar lymph node and muscle attenuation (p = 0.83,0.17), while for all other ROIs, RCM-VMI_40keV showed higher attenuation (p ≤ 0.05). SNR was comparable between RCM-VMI_40keV and SCM images (p range: 0.23-0.99). CNR of lymph nodes was highest in RCM-VMI_40keV (p ≤ 0.05). RCM-VMI_40keV received equivalent or higher scores than SCM in all criteria except for organ contrast, overall assessability and image noise, where SCM were superior (p ≤ 0.05). However, RCM-VMI_40keV received proper or excellent scores in 88.6/94.2/95.4% of the referring cases.

CONCLUSIONS

VMI_40keV counteract contrast deterioration in CM reduced abdominal SDCT, facilitating diagnostic assessment.

ADVANCES IN KNOWLEDGE

SDCT-derived VMI_40keV provide adequate depiction of vessels, organs and lymph nodes even at notable CM reduction.