Association of advanced hepatic fibrosis and sonographic visualization score: a dual-center study using ACR US LI-RADS

Surveillance for malignant progression of LI-RADS version 2017 category 3/4 nodules using contrast-enhanced ultrasound

OBJECTIVES

To identify the risk factors for predicting the malignant progression of LR-3/4 observations on the baseline and contrast-enhanced ultrasound (CEUS).

METHODS

In total, 245 liver nodules assigned to LR-3/4 in 192 patients from January 2010 to December 2016 were followed up by baseline US and CEUS. The differences in the rate and time of progression to hepatocellular carcinoma (HCC) among subcategories (defined as P1-P7) of LR-3/4 in CEUS Liver Imaging Reporting and Data System (LI-RADS) were analyzed. The risk factors to predict progression to HCC were analyzed by univariate and multivariate Cox proportional hazard model analysis.

RESULTS

A total of 40.3% of LR-3 nodules and 78.9% of LR-4 nodules eventually progressed to HCC. The cumulative incidence of progression was significantly higher for LR-4 than LR-3 (p < 0.001). The rate of progression was 81.2% in nodules with arterial phase hyperenhancement (APHE), 64.7% in nodules with late and mild washout, and 100% in nodules with both characteristics. The overall progression rate and median progression time of subcategory P1 nodules (LR-3a) were lower (38.0% vs. 47.6-100.0%) and later (25.1 months vs. 2.0-16.3 months) than those of other subcategories. The cumulative incidence of progression of LR-3a (P1), LR-3b (P2/3/4), and LR-4 (P5/6/7) categories were 38.0%, 52.9%, and 78.9%. The risk factors of HCC progression were Visualization score B/C, CEUS characteristics (APHE, washout), LR-4 classification, echo changes, and definite growth.

CONCLUSION

CEUS is a useful surveillance tool for nodules at risk of HCC. CEUS characteristics, LI-RADS classification, and changes in nodules provide useful information for the progress of LR-3/4 nodules.

CLINICAL RELEVANCE STATEMENT

CEUS characteristics, LI-RADS classification, and nodule changes provide important predictions for LR-3/4 nodule progression to HCC, which may stratify the risk of malignant progression to provide a more optimized and refined, more cost-effective, and time-efficient management strategy for patients.

KEY POINTS

• CEUS is a useful surveillance tool for nodules at risk of HCC, CEUS LI-RADS successfully stratified the risks that progress to HCC. • CEUS characteristics, LI-RADS classification, and changes in nodules can provide important information on the progression of LR-3/4 nodules, which may be helpful for a more optimized and refined management strategy.

Ultrasound LI-RADS Visualization Scores on Surveillance Ultrasound for Hepatocellular Carcinoma: A Systematic Review With Meta-analysis

We performed a systematic review and meta-analysis to determine the proportions of each surveillance ultrasound (US) visualization score for hepatocellular carcinoma based on the US Liver Imaging Reporting and Data System (LI-RADS) and to identify the factors associated with visualization score C. Original publications reporting US LI-RADS visualization scores were identified in MEDLINE and EMBASE from January 1, 2017, to November 25, 2022. The meta-analytic pooled proportion of each visualization score based on US examination was calculated using the DerSimonian‒Laird random-effects model. Subgroup meta-regression analyses were performed to explore study heterogeneity. US LI-RADS visualization scores were reported from a total of 25,698 US examinations across 12 studies. The pooled proportions of visualization scores A, B and C were 56.7% (95% confidence interval [CI]: 38.6-73.2%, I2 = 99.2%), 30.3% (95% CI: 21.5-40.7%, I2 = 98.8%) and 6.9% (95% CI: 3.9-11.7%, I2 = 97.7%), respectively. Significantly higher proportions of visualization score C were found in studies that exclusively enrolled cirrhosis patients and a study in which the disease etiology was non-alcoholic fatty liver disease (NAFLD) (p < 0.05). In addition, the pooled proportion of visualization score C was higher in studies with a mean or median body mass index >25 kg/m2 (10.7%, 95% CI: 4.3-24.3%). In conclusion, a substantial proportion of surveillance US examinations exhibited moderate to severe limitations on visualization. There was a tendency toward higher proportions of US LI-RADS visualization score C in patients with cirrhosis, NAFLD and obesity.

Quality Assessment of Ultrasound and Magnetic Resonance Imaging for Hepatocellular Carcinoma Surveillance: A Systematic Review and Meta-Analysis

INTRODUCTION

To achieve early detection and curative treatment options, surveillance imaging for hepatocellular carcinoma (HCC) must remain of quality and without substantial limitations in liver visualization. However, the prevalence of limited liver visualization during HCC surveillance imaging has not been systematically assessed. Utilizing a systematic review and meta-analytic approach, we aimed to determine the prevalence of limited liver visualization during HCC surveillance imaging.

METHODS

MEDLINE and Embase electronic databases were searched to identify published data on liver visualization limitations of HCC surveillance imaging. An analysis of proportions was pooled using a generalized linear mixed model with Clopper-Pearson intervals. Risk factors were analysed using a generalized mixed model with a logit link and inverse variance weightage.

RESULTS

Of 683 records, 10 studies (7,131 patients) met inclusion criteria. Seven studies provided data on liver visualization limitations on ultrasound (US) surveillance exams: prevalence of limited liver visualization was 48.9% (95% CI: 23.5-74.9%) in the overall analysis and 59.2% (95% CI: 24.2-86.9%) in a sensitivity analysis for cirrhotic patients. Meta-regression determined that non-alcoholic fatty liver disease was associated with limited liver visualization on US. Four studies provided data for liver visualization limitations in abbreviated magnetic resonance imaging (aMRI), with inadequate visualization ranging from 5.8% to 19.0%. One study provided data for complete MRI and none for computed tomography.

CONCLUSION

A substantial proportion of US exams performed for HCC surveillance provide limited liver visualization, especially in cirrhosis, which may hinder detection of small observations. Alternative surveillance strategies including aMRI may be appropriate for patients with limited US visualization.

Multicenter Study of ACR Ultrasound LI-RADS Visualization Scores on Serial Examinations: Implications for Changes in Surveillance Strategies

Background: American College of Radiology Ultrasound LI-RADS includes the visualization score as a subjective measure of examination quality and expected level of sensitivity. Whether a single suboptimal visualization score warrants change in surveillance strategy is unknown. Objective: To determine the relative stability of visualization scores on serial surveillance ultrasound examinations in patients at risk for HCC. Methods: This retrospective study included patients at risk for HCC who underwent at least two HCC surveillance ultrasound examinations at one of three institutions between January 2017 and November 2020. Frequencies of score remaining unchanged after variable numbers of preceding examinations with the given score were determined. A mixed-effects logistic model was fitted to identify factors associated with a repeat score C (severe limitations) versus change to score A (no or minimal limitations) or score B (moderate limitations). Results: A total of 3169 patients underwent at least 2 ultrasound examinations, yielding a total of 9602 examinations. A total of 8030 (83.6%) examinations had score A, 1378 (14.4%) score B, and 194 (2.0%) score C. Frequency of score A was 88%, 91%, and 93% after 1, 2 and 3 consecutive prior examinations with score A. Frequency of score B was 45%, 48%, and 55% after 1, 2, and 3 consecutive prior examinations with score B. Frequency of score C was 42%, 67%, and 80% after 1, 2, and 3 consecutive prior examinations with score C. Among 109 examinations with score C in 91 patients with an available follow-up examination, no factor (including age, sex, severe steatosis, advanced cirrhosis, ascites, body mass index, and change in ultrasound machine, sonographer, or radiologist) was significantly associated with repeat score C (all p>.05). Although not statistically significant, presence of severe steatosis and advanced cirrhosis had the highest odds ratios (2.88 and 2.38, respectively) for repeat score C in multivariable analysis. Conclusion: Only 42% of patients with visualization score C on surveillances examination have score C on follow-up examination. Clinical Impact: The findings may inform decisions for alternative surveillance strategies in patients with visualization score C on ultrasound. This decision should consider the number of previous examinations with score C.

Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) Visualization Score: a reliability analysis on inter-reader agreement

BACKGROUND & AIM

The American College of Radiology Ultrasound Liver Imaging Reporting and Data System (ACR US LI-RADS) Visualization Score conveys the expected level of sensitivity of screening and surveillance ultrasound exams in patients at risk for hepatocellular carcinoma (HCC). We sought to determine inter-reader agreement of the Visualization Score which is currently unknown.

METHODS

Consecutive 6998 ultrasound HCC screening and surveillance studies in 3115 patients from 2017 to 2020 were retrospectively retrieved. Of these, 6154 (87.9%) studies were Visualization A (No or minimal limitations), 709 (10.1%) were Visualization B (Moderate limitations), and 135 (1.9%) were Visualization C (Severe limitations). Randomly sampled 90 studies, with 30 studies in each Visualization category, were included for analysis. Nine radiologists (3 senior attendings, 3 junior attendings and 3 body imaging fellows) blinded to the original categorization independently reviewed each study and assigned a Visualization Score. Intraclass correlation coefficient (ICC) was used to quantify inter-reader agreement.

RESULTS

ICC among all 9 radiologists was 0.70 (95% CI 0.63-0.77). ICCs among senior attendings, junior attendings and body imaging fellows were 0.68 (CI 0.58-0.76), 0.72 (CI 0.62-0.80) and 0.76 (CI 0.68-0.83), respectively. Subgroup analysis by liver parenchyma was further performed. ICC was highest in the patient group with normal liver parenchyma (0.69, CI 0.56-0.81), followed by steatosis (0.66, CI 0.54-0.79) and cirrhosis (0.58, CI 0.43-0.73), respectively.

CONCLUSIONS

US LI-RADS Visualization Score is a reliable tool with good inter-reader agreement that can be used to indicate the expected level of sensitivity of a screening and surveillance ultrasound examination for detecting focal liver observations.

HCC Detection on Surveillance US: Comparing Focused Liver Protocol Using US LI-RADS Technical Guidelines to a General Complete Abdominal US Protocol

OBJECTIVE

Focused US examinations of the liver in the routine hepatocellular carcinoma (HCC) screening reduce the time spent on evaluating other structures deemed irrelevant to the clinical setting. It is still unknown, however, if such a strategy may additionally improve the frequency of nodules detection. We aimed to assess the impact of an HCC surveillance program in high-risk patients by means of targeted liver US following LI-RADS technical guidelines in comparison to a complete upper abdominal scan.

METHODS

In this IRB-approved, single-center, prospective study, patients at high-risk for HCC enrolled from 06/2016 to 09/2019 were randomly assigned to 1 of the 2 institutional protocols: Group A (targeted liver US) or Group B (complete upper abdominal scan). Twenty examiners with similar experience in abdominal US were randomly assigned to perform the examinations exclusively in 1 of the groups (10 in each group). Frequency of hepatic nodules between groups was compared by using Fisher's exact test.

RESULTS

Four hundred and sixty-five patients were enrolled, with no significant differences in both groups regarding sex, age, etiology of liver disease, MELD scores, and alpha-fetoprotein levels. A significantly higher frequency of nodules detection was found in Group A (230 patients; 23 nodules detected; 10% of the sample) in comparison to Group B (235 patients; 3 nodules; 1.3% of the sample) (p <.001). Five patients in Group A and 1 in Group B were positive for HCC after full diagnostic work-up.

CONCLUSION

Adopting an HCC screening program based on targeted liver US improved the detection of hepatic nodules among high-risk individuals.

Ultrasound Liver Imaging Reporting and Data System (US LI-RADS): An Overview with Technical and Practical Applications

The Ultrasound Liver Imaging Reporting and Data System (US LI-RADS), introduced in 2017 by the American College of Radiology, standardizes the technique, interpretation, and reporting of screening and surveillance ultrasounds intended to detect hepatocellular carcinoma in high-risk patients. These include patients with cirrhosis of any cause as well as subsets of patients with chronic hepatitis B viral infection. The US LI-RADS scheme is composed of an ultrasound category and a visualization score: ultrasound categories define the exam as negative, subthreshold, or positive and direct next steps in management; visualization scores denote the expected sensitivity of the exam, based on adequacy of liver visualization with ultrasound. Since its introduction, multiple institutions across the United States have implemented US LI-RADS. This review includes a background of hepatocellular carcinoma and US LI-RADS, definition of screening/surveillance population, recommendations and tips for technique, interpretation, and reporting, and preliminary outcomes analysis.

Ultrasound (US) LI-RADS: Outcomes of Category US-3 Observations

OBJECTIVE. The purpose of the study is to evaluate the outcomes of ultrasound (US) LI-RADS category US-3 observations detected at US performed for hepatocellular carcinoma (HCC) screening and surveillance on the basis of subsequently performed multi-phase MRI or CT or histopathology. MATERIALS AND METHODS. In this retrospective analysis, 267 patients at high risk for HCC (161 men and 106 women; mean [± SD] age, 58.6 ± 12.2 years) underwent screening liver US between January 2017 and June 2019 and were assigned US-3 observations on a prospective clinical basis using the US LI-RADS algorithm. The results of follow-up imaging studies and/or histopathology were analyzed. RESULTS. Visualization scores assigned at US were A (40.8% [109/267]), B (52.8% [141/267]), and C (6.4% [17/267]). Reasons for US-3 observations included a measurable mass of 1 cm or larger (88.8% [237/267]; mean size, 1.8 ± 1.0 cm; range, 1.0-6.9 cm), an area of parenchymal distortion of 1 cm or greater (7.9% [21/267]; mean size, 1.8 ± 0.9 cm; range, 1.0-4.0 cm), or a new venous thrombus (3.4% [9/267]). Confirmatory testing with multiphase contrast-enhanced MRI or CT or with histopathology was available for 81.6% (218/267) of patients. Causes of US-3 observations included no abnormality at MRI or CT (41.3% [90/218]), a benign lesion (32.6% [71/218]), a LI-RADS category 3 (LR-3) observation at MRI or CT (5.5% [12/218]), a LI-RADS category 4 or 5 (LR-4 or LR-5) observation at MRI or CT or identification of HCC at histopathology (18.8% [41/218]), and an LR-M (denoting probably or definitely malignant but without specific features for HCC) observation at MRI or CT or other malignancy at histopathology (1.8% [4/218]). The PPV of a US-3 observation for probable or definite HCC was 18.8%, and for any malignancy it was 20.6%. CONCLUSION. In the HCC screening population, approximately one in five US-3 observations represents probable or definite HCC at multiphase MRI or CT or HCC at histopathology. These findings support current US LI-RADS guidelines to pursue further evaluation with multiphase cross-sectional imaging for US-3 observations.

US LI-RADS Visualization Score: Interobserver Variability and Association With Cause of Liver Disease, Sex, and Body Mass Index

OBJECTIVES

To evaluate the interobserver agreement between radiologists using the Ultrasound Liver Reporting And Data System (US LI-RADS) visualization score and assess association between visualization score and cause of liver disease, sex, and body mass index (BMI).

METHODS

This retrospective, single institution, cross-sectional study evaluated 237 consecutive hepatocellular carcinoma surveillance US examinations between March 4, 2017 and September 4, 2017. Five abdominal radiologists independently assigned a US LI-RADS visualization score (A, no or minimal limitations; B, moderate limitations; C, severe limitations). Interobserver agreement was assessed with a weighted Kappa statistic. Association between US visualization score (A vs B or C) and cause of liver disease, sex, and BMI (< or ≥ 25 kg/m²) was evaluated using univariate and multivariate analyses.

RESULTS

The average weighted Kappa statistic for all raters was 0.51. A score of either B or C was assigned by the majority of radiologists in 148/237 cases and was significantly associated with cause of liver disease (P = 0.014) and elevated BMI (P < 0.001). Subjects with viral liver disease were 3.32 times (95% CI: 1.44-8.38) more likely to have a score of A than those with non-alcoholic steatohepatitis (P = 0.007). The adjusted odds ratio of visualization score A was 0.249 (95% CI: 0.13-0.48) among those whose BMI was ≥25 kg/m² vs. BMI < 25 kg/m².

CONCLUSION

Interobserver agreement between radiologists using US LI-RADS score was moderate. The majority of US examinations were scored as having moderate or severe limitations, and this was significantly associated with non-alcoholic steatohepatitis and increased BMI.

Current status of image-based surveillance in hepatocellular carcinoma

Although the overall prognosis of patients with hepatocellular carcinoma (HCC) remains poor, curative treatment may improve the survival of patients diagnosed at an early stage through surveillance. Accordingly, ultrasonography (US)-based HCC surveillance programs proposed in international society guidelines are now being implemented and regularly updated based on the latest evidence to improve their efficacy. Recently, other imaging modalities such as magnetic resonance imaging have shown potential as alternative surveillance tools based on individualized risk stratification. In this review article, we describe the current status of US-based surveillance for HCC and summarize the supporting evidence. We also discuss alternative surveillance imaging modalities that are currently being studied to validate their diagnostic performance and cost-effectiveness.