Systematic training of LI-RADS CT v2018 improves interobserver agreements and performances in LR categorization for focal liver lesions

AIM

To retrospectively explored whether systematic training in the use of Liver Imaging Reporting and Data System (LI-RADS) v2018 on computed tomography (CT) can improve the interobserver agreements and performances in LR categorization for focal liver lesions (FLLs) among different radiologists.

MATERIALS AND METHODS

A total of 18 visiting radiologists and the liver multiphase CT images of 70 hepatic observations in 63 patients at high risk of HCC were included in this study. The LI-RADS v2018 training procedure included three thematic lectures, with an interval of 1 month. After each seminar, the radiologists had 1 month to adopt the algorithm into their daily work. The interobserver agreements and performances in LR categorization for FLLs among the radiologists before and after training were compared.

RESULTS

After training, the interobserver agreements in classifying the LR categories for all radiologists were significantly increased for most LR categories (P < 0.001), except for LR-1 (P = 0.053). After systematic training, the areas under the curve (AUCs) for LR categorization performance for all participants were significantly increased for most LR categories (P < 0.001), except for LR-1 (P = 0.062).

CONCLUSION

Systematic training in the use of the LI-RADS can improve the interobserver agreements and performances in LR categorization for FLLs among radiologists with different levels of experience.

The clinical and financial burden of nonhepatocellular carcinoma focal lesions detected during the surveillance of patients with cirrhosis

BACKGROUND AND AIMS

HCC surveillance is challenged by the detection of hepatic focal lesions (HFLs) of other types. This study aimed to describe the incidence, characteristics, outcomes, and costs of non-HCC HFL detected during surveillance.

APPROACH AND RESULTS

We retrospectively analyzed nonstandardized workup performed in French patients included in HCC surveillance programs recruited in 57 French tertiary centers (ANRS CirVir and CIRRAL cohorts, HCC 2000 trial). The overall cost of workup was evaluated, with an estimation of an average cost per patient for the entire population and per lesion detected. A total of 3295 patients were followed up for 59.8 months, 391 (11.9%) patients developed HCCs (5-year incidence: 12.1%), and 633 (19.2%) developed non-HCC HFLs (5-year incidence: 21.8%). Characterization of non-HCC HFL required a median additional of 0.7 exams per year. A total of 11.8% of non-HCC HFLs were not confirmed on recall procedures, and 19.6% of non-HCC HFLs remained undetermined. A definite diagnosis of benign liver lesions was made in 65.1%, and malignant tumors were diagnosed in 3.5%. The survival of patients with benign or undetermined non-HCC HFL was similar to that of patients who never developed any HFL (5-year survival 92% vs. 88%, p = 0.07). The average cost of the diagnostic workup was 1087€ for non-HCC HFL and €1572 for HCC.

CONCLUSIONS

Non-HCC HFLs are frequently detected in patients with cirrhosis, and do not impact prognosis, but trigger substantial costs. This burden must be considered in cost-effectiveness analyses of future personalized surveillance strategies.

Long-term evolution of LR-2, LR-3 and LR-4 observations in HBV-related cirrhosis based on LI-RADS v2018 using gadoxetic acid-enhanced MRI

PURPOSE

To investigate the long-term evolution of LR-2, LR-3 and LR-4 observations in patients with hepatitis B virus (HBV)-related cirrhosis based on LI-RADS v2018 and identify predictors of progression to a malignant category on serial gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI).

METHODS

This retrospective study included 179 cirrhosis patients with untreated indeterminate observations who underwent Gd-EOB-MRI exams at baseline and during the follow-up period between June 2016 and December 2021. Two radiologists independently assessed the major features, ancillary features, and LI-RADS category of each observation at baseline and follow-up. In cases of disagreement, a third radiologist was consulted for consensus. Cumulative incidences for progression to a malignant category (LR-5 or LR-M) and to LR-4 or higher were analyzed for each index category using Kaplan‒Meier methods and compared using log-rank tests. The risk factors for malignant progression were evaluated using a Cox proportional hazard model.

RESULTS

A total of 213 observations, including 74 (34.7%) LR-2, 95 (44.6%) LR-3, and 44 (20.7%) LR-4, were evaluated. The overall cumulative incidence of progression to a malignant category was significantly higher for LR-4 observations than for LR-3 or LR-2 observations (each P < 0.001), and significantly higher for LR-3 observations than for LR-2 observations (P < 0.001); at 3-, 6-, and 12-month follow-ups, the cumulative incidence of progression to a malignant category was 11.4%, 29.5%, and 39.3% for LR-4 observations, 0.0%, 8.5%, and 19.6% for LR-3 observations, and 0.0%, 0.0%, and 0.0% for LR-2 observations, respectively. The cumulative incidence of progression to LR-4 or higher was higher for LR-3 observations than for LR-2 observations (P < 0.001); at 3-, 6-, and 12-month follow-ups, the cumulative incidence of progression to LR-4 or higher was 0.0%, 8.5%, and 24.6% for LR-3 observations, and 0.0%, 0.0%, and 0.0% for LR-2 observations, respectively. In multivariable analysis, nonrim arterial phase hyperenhancement (APHE) [hazard ratio (HR) = 2.13, 95% CI 1.04-4.36; P = 0.038], threshold growth (HR = 6.50, 95% CI 2.88-14.65; P <0.001), and HBP hypointensity (HR = 16.83, 95% CI 3.97-71.34; P <0.001) were significant independent predictors of malignant progression.

CONCLUSION

The higher LI-RADS v2018 categories had an increasing risk of progression to a malignant category during long-term evolution. Nonrim APHE, threshold growth, and HBP hypointensity were the imaging features that were significantly predictive of malignant progression.

Nodules Identified on Surveillance Ultrasound for HCC: CEUS or MRI as the Initial Test?

OBJECTIVES

Following positive surveillance ultrasound (US), magnetic resonance imaging (MRI) is recommended for further characterization. We propose contrast-enhanced ultrasound (CEUS) shows equivalent efficacy.

METHODS

This prospective institutional review board approved study recruited 195 consecutive at-risk patients with a positive surveillance US. All had CEUS and MRI. Biopsy (n = 44) and follow-up are gold standard. MRI and CEUS results are classified according to liver imaging reporting and data system (LI-RADS) and patient outcome.

RESULTS

As an US-based modality, CEUS is superior in confirming findings from surveillance US, correlation in 189/195 (97%) on CEUS compared to 153/195 (79%) on MRI. Within these negative MRI examinations, there are 2 hepatocellular carcinoma (HCC) and 1 cholangiocarcinoma (iCCA) diagnosed on CEUS and proven by biopsy. From 195 patients, there are 71 malignant diagnoses from all sources, including 58 LR-5 (45 on MRI and 54 on CEUS) and 13 others, including HCC outside of LR-5 category, and LR-M with biopsy proven iCCA (3 on MRI and 6 on CEUS). CEUS and MRI show concordant results in the majority of patients (146/195, 75%), including 57/146 malignant and 89/146 benign diagnoses. There are 41/57 concordant LR-5 and 6/57 concordant LR-M. When CEUS and MRI are discordant, CEUS upgraded 20 (10 biopsy-proven) from MRI LR-3/4 to CEUS LR-5 or LR-M by showing washout (WO) that MRI failed to show. Additionally, CEUS characterized time and intensity of WO and diagnosed 13/20 LR-5 by showing late and weak WO and 7 LR-M by showing fast and marked WO. CEUS is 81% sensitive and 92% specific in diagnosing malignancy. MRI is 64% sensitive and 93% specific.

CONCLUSIONS

CEUS performance is at least equivalent if not superior to MRI for initial evaluation of lesions from surveillance US.

Imaging Diagnosis of Hepatocellular Carcinoma: A State-of-the-Art Review

Hepatocellular carcinoma (HCC) remains not only a cause of a considerable part of oncologic mortality, but also a diagnostic and therapeutic challenge for healthcare systems worldwide. Early detection of the disease and consequential adequate therapy are imperative to increase patients' quality of life and survival. Imaging plays, therefore, a crucial role in the surveillance of patients at risk, the detection and diagnosis of HCC nodules, as well as in the follow-up post-treatment. The unique imaging characteristics of HCC lesions, deriving mainly from the assessment of their vascularity on contrast-enhanced computed tomography (CT), magnetic resonance (MR) or contrast-enhanced ultrasound (CEUS), allow for a more accurate, noninvasive diagnosis and staging. The role of imaging in the management of HCC has further expanded beyond the plain confirmation of a suspected diagnosis due to the introduction of ultrasound and hepatobiliary MRI contrast agents, which allow for the detection of hepatocarcinogenesis even at an early stage. Moreover, the recent technological advancements in artificial intelligence (AI) in radiology contribute an important tool for the diagnostic prediction, prognosis and evaluation of treatment response in the clinical course of the disease. This review presents current imaging modalities and their central role in the management of patients at risk and with HCC.

LI-RADS Made Easy

PURPOSE

 The Liver Imaging Reporting and Data System (LI-RADS v2018) standardizes the interpretation and reporting of MDCT and MRI examinations in patients at risk for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

 For focal liver lesions (called "observations") it assigns categories (LR-1 to 5, LR-M, LR-TIV, LR-TR), which reflect the probability of benignity or malignancy (HCC or other non-HCC malignancies) of the respective observation. The categories assigned are based on major and ancillary image features, which have been developed by the American College of Radiology (ACR), revised several times (now v2018), and validated in many studies. The value of ancillary features to modify LI-RADS categories assigned to observations based on major features is shown.

RESULTS

 This review summarizes the relevant CT and MRI features and presents a step-by-step approach for readers not familiar with LI-RADS on how to use the system. Relevant imaging features and the value of different modalities (contrast-enhanced CT, MRI with extracellular gadolinium chelates or liver-specific contrast agents) is explained.

CONCLUSION

 The widespread adoption of LI-RADS for CT/MRI reporting in high-risk patients would help to reduce inter-reader variability. It could improve communication between radiologists, oncologists, hepatologists, pathologists, and liver surgeons, and lead to better patient management.

KEY POINTS

  · LI-RADS has been developed and revised to address the need for improved diagnosis and standardized categorization of findings in chronic liver disease.. · CT/MRI LI-RADS consists of major criteria and ancillary features to classify observations.. · LI-RADS terminology helps to clarify the communication of liver observations between radiologists and referring physicians..

CITATION FORMAT

· Schima W, Kopf H, Eisenhuber E. LI-RADS made Easy. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1990-5924.

Clinical outcomes of patients with Liver Imaging Reporting and Data System 3 or Liver Imaging Reporting and Data System 4 observations in patients with cirrhosis: A systematic review

Patients with indeterminate liver nodules, classified as LR-3 and LR-4 observations per the Liver Imaging Reporting and Data System, are at risk of developing hepatocellular carcinoma (HCC), but risk estimates remain imprecise. We conducted a systematic review of Ovid MEDLINE, EMBASE, and Cochrane databases from inception to December 2021 to identify cohort studies examining HCC incidence among patients with LR-3 or LR-4 observations on computed tomography (CT) or magnetic resonance imaging (MRI). Predictors of HCC were abstracted from each study, when available. Of 13 total studies, nine conducted LR-3 observation-level analyses, with the proportions of incident HCC ranging from 1.2% to 12.5% at 12 months and 4.2% to 44.4% during longer study follow-up. Among three studies with patient-level analyses, 8%-22.2% of patients with LR-3 lesions developed LR-4 observations and 11.1%-24.5% developed HCC. Among nine studies conducting LR-4 observation-level analyses, incident HCC ranged from 30.8% to 44.0% at 12 months and 30.9% to 71.0% during study follow-up; conversely, 6%-42% of observations were downgraded to LR-3 or lower. Patient-level factors associated with HCC included older age, male sex, higher alpha-fetoprotein levels, viral etiology, and prior history of HCC; observation-level factors included maximum diameter, threshold growth, T2 hyperintensity, and visibility on ultrasound. Studies were limited by small sample sizes, inclusion of patients with prior HCC, short follow-up duration, and failure to account for clustering of observations in patients or competing risks of transplantation and death. LR-3 and LR-4 observations have elevated but variable risks of HCC. Higher quality studies are necessary to identify high-risk patients who warrant close CT or MRI-based follow-up.

Liver Imaging Reporting and Data System categories: Long-term imaging outcomes in a prospective surveillance cohort

BACKGROUND AND AIMS

We assessed the imaging outcomes of Liver Imaging Reporting and Data System (LI-RADS) v2018 categories in prospective hepatocellular carcinoma (HCC) surveillance cohort and determined imaging features significantly predictive of progression to a malignant LI-RADS category.

METHODS

The imaging outcomes of 120 patients (162 observations) prospectively enrolled between November 2011 and August 2012 were analysed according to LI-RADS v2018. Cumulative incidences for progression to a malignant category (LR-5 or LR-M) and LR-4 or higher were calculated for each baseline category and compared using log-rank tests. Clinical variables and imaging features significantly predictive of progression to a malignant category were evaluated using Cox proportional hazards modelling.

RESULTS

The 162 observations were initially categorized into 60 LR-2, 75 LR-3 and 27 LR-4. For LR-4 observations, the 1-year, 3-year and 5-year cumulative incidences of progression to a malignant category were 18.5% (95% confidence interval, 6.6-35.2%), 43.0% (23.1-61.5%) and 52.5% (25.9-73.5%), which were significantly higher than those of LR-2 and LR-3 (p  < .001). For LR-3, the 1-year, 3-year and 5-year cumulative incidences of progression to LR-4 or higher were 4.1% (1.1-10.4%), 13.9% (6.7-23.6%) and 23.1% (12.7-35.4%), which were significantly higher than that of LR-2 (p  = .009). In multivariable analysis, size ≥1.0 cm (hazard ratio [HR] = 2.58, 1.04-6.40) and nonrim arterial-phase hyperenhancement (HR = 2.45, 1.11-5.42) were significantly independently associated with progression to a malignant category.

CONCLUSION

Long-term imaging outcomes differed significantly according to LI-RADS category. Size ≥1.0 cm and nonrim arterial-phase hyperenhancement were imaging features significantly predictive of progression to a malignant category.

Risk Stratification and Distribution of Hepatocellular Carcinomas in CEUS and CT/MRI LI-RADS: A Meta-Analysis

Background

CEUS LI-RADS and CT/MRI LI-RADS have been used in clinical practice for several years. However, there is a lack of evidence-based study to compare the proportion of hepatocellular carcinomas (HCCs) in each category and the distribution of HCCs of these two categorization systems.

Purpose

The purpose of this study was to compare the proportion of HCCs between corresponding CEUS LI-RADS and CT/MRI LI-RADS categories and the distribution of HCCs and non-HCC malignancies in each category.

Methods

We searched PubMed, Embase, and Cochrane Central databases from January 2014 to December 2021. The proportion of HCCs and non-HCC malignancies and the corresponding sensitivity, specificity, accuracy, diagnostic odds ratio (DOR), and area under the curve (AUC) of the LR-5 and LR-M categories were determined using a random-effect model.

Results

A total of 43 studies were included. The proportion of HCCs in CEUS LR-5 was 96%, and that in CECT/MRI LR-5 was 95% (p > 0.05). The proportion of non-HCC malignancy in CEUS LR-M was lower than that of CT/MRI LR-M (35% vs. 58%, p = 0.01). The sensitivity, specificity, and accuracy of CEUS LR-5 for HCCs were 73%, 92%, and 78%, respectively, and of CT/MRI LR-5 for HCCs, 69%, 92%, and 76%, respectively.

Conclusion

With the upshift of the LI-RADS category, the proportion of HCCs increased. CEUS LR-3 has a lower risk of HCCs than CT/MRI LR-3. CEUS LR-5 and CT/MRI LR-5 have a similar diagnostic performance for HCCs. CEUS LR-M has a higher proportion of HCCs and a lower proportion of non-HCC malignancies compared with CT/MRI LR-M.

Long-term evolution of LI-RADS observations in HCV-related cirrhosis treated with direct-acting antivirals

BACKGROUND & AIMS

The risk of progression of indeterminate observations to hepatocellular carcinoma (HCC) after direct-acting antivirals (DAA) is still undetermined. To assess whether DAA therapy changes the risk of progression of observations with low (LR-2), intermediate (LR-3) and high (LR-4) probability for HCC in cirrhotic patients and to identify predictors of progression.

METHODS

This retrospective study included cirrhotic patients treated with DAA who achieved sustained virological response between 2015 and 2019. A total of 68 patients had pre-DAA indeterminate observations and at least six months CT/MRI follow-up before and after DAA. Two radiologists reviewed CT/MRI studies to categorize observations according to the LI-RADSv2018 and assess the evolution on subsequent follow-ups. Predictors of evolutions were evaluated by using the Cox proportional hazard model, Kaplan-Meier method and log-rank test.

RESULTS

A total of 109 untreated observations were evaluated, including 31 (28.4%) LR-2, 67 (61.5%) LR-3 and 11 (10.1%) LR-4. During a median follow-up of 41 months, 17.4% and 13.3% of observations evolved to LR-5 or LR-M and LR-5, before and after DAA respectively (P = .428). There was no difference in rate of progression of neither LR-2 (P = 1.000), LR-3 (P = .833) or LR-4 (P = .505). At multivariate analysis, only initial LI-RADS category was an independent predictor of progression to LR-5 or LR-M for all observations (hazard ratio 6.75, P < .001), and of progression to LR-5 after DAA (hazard ratio 4.34, P = .047).

CONCLUSIONS

DAA therapy does not increase progression of indeterminate observations to malignant categories. The initial LI-RADS category is an independent predictor of observations upgrade.

Systematic Training of Liver Imaging Reporting and Data System Magnetic Resonance Imaging v2018 can Improve the Diagnosis of Hepatocellular Carcinoma for Different Radiologists

BACKGROUND AND AIMS

Liver imaging reporting and data system (LI-RADS) provides standardized lexicon and categorization for diagnosing hepatocellular carcinoma (HCC). However, there is limited knowledge about the effect of LI-RADS training. We prospectively explored whether the systematic training of LI-RADS v2018 on magnetic resonance imaging (MRI) can effectively improve the diagnostic performances of different radiologists for HCC.

METHODS

A total of 20 visiting radiologists and the multiparametric MRI of 70 hepatic observations in 61 patients with high risk of HCC were included in this study. The LI-RADS v2018 training procedure included three times of thematic lectures (each lasting for 2.5 h) given by a professor specialized in imaging diagnosis of liver, with an interval of a month. After each seminar, the radiologists had a month to adopt the algorithm into their daily work. The diagnostic performances and interobserver agreements of these radiologists adopting the algorithm for HCC diagnosis before and after training were compared.

RESULTS

A total of 20 radiologists (male/female, 12/8; with an average age of 36.75±4.99 years) were enrolled. After training, the interobserver agreements for the LI-RADS category for all radiologists (p=0.005) were increased. The sensitivity, specificity, positive predictive value, negative predictive value, and coincidence rate of all radiologists for HCC diagnosis before and after training were 43% vs. 54%, 86% vs. 88%, 74% vs. 81%, 62% vs. 67%, and 65% vs. 71%, respectively. The diagnostic performances of all radiologists (p<0.001) showed improvement after training.

CONCLUSIONS

The systematic training of LI-RADS can effectively improve the diagnostic performances of radiologists with different experiences for HCC.

Evaluation of LI-RADS 3 category by magnetic resonance in US-detected nodules ≤ 2 cm in cirrhotic patients

OBJECTIVES

Liver Imaging Reporting and Data System (LI-RADS) for hepatocellular carcinoma (HCC) diagnosis in high-risk patients is a dynamic system, which was lastly updated in 2018. We aimed to evaluate the accuracy for HCC diagnosis of LI-RADS v2018 with magnetic resonance imaging (MRI) with extracellular contrast for solitary nodules ≤ 20 mm detected during ultrasound (US) surveillance in cirrhotic patients, with particular interest in those observations categorized as LI-RADS 3.

METHODS

Between November 2003 and February 2017, we included 262 consecutive cirrhotic patients with a newly US-detected solitary ≤ 20-mm nodule. A LI-RADS (LR) v2018 category was retrospectively assigned. The diagnostic accuracy for each LR category was described, and the main MRI findings associated with HCC diagnosis were analyzed.

RESULTS

Final diagnoses were as follows: 197 HCC (75.2%), 5 cholangiocarcinoma (1.9%), 2 metastasis (0.8%), and 58 benign lesions (22.1%); 0/15 (0%) LR-1, 6/26 (23.1%) LR-2, 51/74 (68.9%) LR-3, 11/12 (91.7%) LR-4, 126/127 (99.2%) LR-5, and 3/8 (37.5%) LR-M were HCC. LR-5 category displayed a sensitivity and specificity of 64% (95% CI, 56.8-70.7) and 98.5% (95% CI, 91.7-100), respectively. Considering also LR-4 as diagnostic for HCC, the sensitivity slightly increased to 69.5% (95% CI, 62.6-75.9) with minor impact on specificity (96.2%; 95% CI, 89.3-99.6). Regarding LR-3 observations, 51 out of 74 were HCC, 2 were non-HCC malignancies, and 20 out of 21 LR-3 nodules > 15 mm (95.2%) were finally categorized as HCC.

CONCLUSIONS

The high probability of HCC in US-detected LR-3 observations (68.9%) justifies triggering an active diagnostic work-up if intended to diagnose HCC at a very early stage.

KEY POINTS

• In cirrhotic patients with nodules ≤ 20 mm detected during US surveillance, 51 out of 74 (68.9%) of LR-3 nodules by MRI corresponded to an HCC. • In LR-3 nodules, HCC diagnosis was closely related to baseline tumor size. All 5 nodules smaller than 1 cm were diagnosed as benign. Oppositely, 20 out of 21 LR-3 observations > 15 mm (95.2%) were diagnosed as HCC. • The high probability of HCC in US-detected LR-3 observations justifies triggering an active diagnostic work-up if intended to diagnose HCC at a very early stage.

MRI Ancillary Features for LI-RADS Category 3 and 4 Observations: Improved Categorization to Indicate the Risk of Hepatic Malignancy

OBJECTIVE. The purpose of this study was to investigate whether ancillary features can help stratify malignancy risk in Liver Imaging Reporting and Data System (LI-RADS) category 3 (LR-3) and 4 (LR-4) observations. MATERIALS AND METHODS. This retrospective longitudinal study included 106 LR-3 or LR-4 observations on gadolinium-enhanced MRI obtained from January 2014 to December 2015 in 80 patients who were treatment naïve and at risk (mean age, 58.0 ± 10.7 [SD] years; 60 men). The presence of major and ancillary features, the category determined using only major features, and the final category adjusted by the application of ancillary features were retrospectively analyzed. MRI features were compared using generalized estimating equations, and cumulative incidence curves for malignancy were compared using log-rank tests with a resampling extension. RESULTS. At 6-month follow-up, the cumulative incidence of observations initially categorized as LR-4, observations upgraded to LR-4, observations initially categorized as LR-3, and observations downgraded to LR-3 were 62.5%, 29.7%, 6.2%, and 0%, respectively. The cumulative incidence of malignancy did not differ between observations categorized by major feature as LR-3 and LR-4 (p = 0.12), but was higher in final observations categorized as LR-4 than in those categorized as LR-3 (p < 0.001). Among observations categorized by major feature as LR-3, the cumulative incidence of malignancy was higher in observations upgraded to LR-4 than in observations that were initially graded as LR-3 (p = 0.03), which showed differences in the frequency of restricted diffusion and mild-to-moderate T2-weighted hyperintensity (p < 0.001 for both). CONCLUSION. Final categories determined with ancillary features, instead of categories determined by major features only, can help indicate malignancy risk in LR-3 and LR-4 observations on MRI.

LI-RADS ancillary feature prediction of longitudinal category changes in LR-3 observations: an exploratory study

PURPOSE

To determine whether LI-RADS ancillary features predict longitudinal LR-3 observation category changes.

MATERIALS AND METHODS

This exploratory, retrospective, single-center study with an independent reading center included patients who underwent two or more multiphase CT or MRI examinations for hepatocellular carcinoma assessment between 2011 and 2015. Three readers independently evaluated each observation using CT/MRI LI-RADS v2017, and observations categorized LR-3 using major features only were included in the analysis. Prevalence of major and ancillary features was calculated. After excluding low-frequency (< 5%) features, inter-reader agreement was assessed using intraclass correlation coefficient (ICC). Major and ancillary feature prediction of observation upgrade (to LR-4 or higher) or downgrade (to LR-1 or LR-2) on follow-up imaging was assessed using logistic regression.

RESULTS

141 LR-3 observations in 79 patients were included. Arterial phase hyperenhancement, washout, restricted diffusion, mild-moderate T2 hyperintensity, and hepatobiliary phase hypointensity were frequent enough for further analysis (consensus prevalence 5.0-66.0%). ICCs for inter-reader agreement ranged from 0.18 for restricted diffusion to 0.48 for hepatobiliary phase hypointensity. On follow-up, 40% (57/141) of baseline LR-3 observations remained LR-3. 8% (11/141) were downgraded to LR-2, and 42% (59/141) were downgraded to LR-1. A small number were ultimately upgraded to LR-4 (2%, 3/141) or LR-5 (8%, 11/141). None of the assessed major or ancillary features was significantly associated with observation category change. Longer follow-up time was significantly associated with both observation upgrade and downgrade.

CONCLUSION

While numerous ancillary features are described in LI-RADS, most are rarely present and are not useful predictors of LR-3 observation category changes.

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.

Deep learning LI-RADS grading system based on contrast enhanced multiphase MRI for differentiation between LR-3 and LR-4/LR-5 liver tumors

Background

To develop a deep learning (DL) method based on multiphase, contrast-enhanced (CE) magnetic resonance imaging (MRI) to distinguish Liver Imaging Reporting and Data System (LI-RADS) grade 3 (LR-3) liver tumors from combined higher-grades 4 and 5 (LR-4/LR-5) tumors for hepatocellular carcinoma (HCC) diagnosis.

Methods

A total of 89 untreated LI-RADS-graded liver tumors (35 LR-3, 14 LR-4, and 40 LR-5) were identified based on the radiology MRI interpretation reports. Multiphase 3D T1-weighted gradient echo imaging was acquired at six time points: pre-contrast, four phases immediately post-contrast, and one hepatobiliary phase after intravenous injection of gadoxetate disodium. Image co-registration was performed across all phases on the center tumor slice to correct motion. A rectangular tumor box centered on the tumor area was drawn to extract subset tumor images for each imaging phase, which were used as the inputs to a convolutional neural network (CNN). The pre-trained AlexNet CNN model underwent transfer learning using liver MRI data for LI-RADS tumor grade classification. The output probability number closer to 1 or 0 indicated a higher possibility of being combined LR-4/LR-5 tumor or LR-3 tumor, respectively. Five-fold cross validation was used for training (60% dataset), validation (20%) and testing processes (20%).

Results

The DL CNN model for LI-RADS grading using inputs of multiphase liver MRI data acquired at three time points (pre-contrast, arterial, and washout phase) achieved a high accuracy of 0.90, sensitivity of 1.0, precision of 0.835, and AUC of 0.95 with reference to the expert human radiologist report. The CNN output of probability provided radiologists a confidence level of the model’s grading for each liver lesion.

Conclusions

An AlexNet CNN model for LI-RADS grading of liver lesions provided diagnostic performance comparable to radiologists and offered valuable clinical guidance for differentiating intermediate LR-3 liver lesions from more-likely malignant LR-4/LR-5 lesions in HCC diagnosis.

Hepatobiliary phase hypointensity predicts progression to hepatocellular carcinoma for intermediate-high risk observations, but not time to progression

PURPOSE

To determine whether hepatobiliary phase hypointensity, enhancing "capsule" and size provide prognostic information regarding the risk of progression to hepatocellular carcinoma (HCC), as well as the time to progression, of intermediate to high risk observations ≥ 10 mm with arterial phase hyperenhancement (APHE).

METHOD

This retrospective dual-institution study included 160 LR-3 and 26 LR-4 observations measuring more than 10 mm and having APHE in 136 patients (mean age [SD], 57 [11] years old). A composite reference standard of pathologic analysis and imaging follow-up was used. The prognostic performance of hepatobiliary phase hypointensity, enhancing "capsule" and size (cut-off: 20 mm) for the prediction of probability of progression to HCC and median time to progression to HCC was assessed and compared by means of Log-rank test, Cox-regression and Kaplan-Meier curves.

RESULTS

110 (59%) of 186 of observations progressed to HCC, 29.1% (32) progressed within 6 months, 60% (66) within 1 year and 84.5% (93) within 2 years. Hepatobiliary phase hypointensity was a significant predictor of progression to HCC (p < 0.0001, odds ratio: 20.62) but not of time to progression (p = 0.17). Median time to progression to HCC was 284 days [IQR: 266-363] and was shorter - though not significantly - for observations with enhancing "capsule" (118 days vs 301 days; p = 0.19).

CONCLUSIONS

Hepatobiliary phase hypointensity is an independent predictor of progression to HCC in intermediate to high risk APHE observations ≥ 10 mm.

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

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

Liver Imaging Reporting and Data System (LI-RADS) v2018: diagnostic value of ancillary features favoring malignancy in hypervascular observations ≥ 10 mm at intermediate (LR-3) and high probability (LR-4) for hepatocellular carcinoma

OBJECTIVE

This study was conducted in order to assess the diagnostic accuracy of LI-RADS v2018 ancillary features (AFs) favoring malignancy applied to LR-3 and LR-4 observations on gadoxetate-enhanced MRI.

METHODS

In this retrospective dual-institution study, we included consecutive patients at high risk for hepatocellular carcinoma (HCC) imaged with gadoxetate disodium-enhanced MRI between 2009 and 2014 fulfilling the following criteria: (i) at least one LR-3 or LR-4 observation ≥ 10 mm; (ii) nonrim arterial phase hyperenhancement; and (iii) confirmation of benignity or malignancy by pathology or imaging follow-up. We compared the distribution of AFs between HCCs and benign observations and the diagnostic performance for the diagnosis of HCC using univariate and multivariate analyses. Significance was set at p value < 0.05.

RESULTS

Two hundred five observations were selected in 155 patients (108 M, 47 F) including 167 (81.5%) LR-3 and 38 (18.5%) LR-4. There were 126 (61.5%) HCCs and 79 (28.5%) benign lesions. A significantly larger number of AFs favoring malignancy were found in LR-3 and LR-4 lesions that progressed to HCC compared to benign lesions (p < 0.001 and p = 0.003, respectively). The most common AFs favoring malignancy in HCCs were hepatobiliary phase (HBP) hypointensity (p < 0.001), transitional phase hypointensity (p < 0.001), and mild-moderate T2 hyperintensity (p < 0.001). Sensitivity and specificity of AFs for the diagnosis of HCC ranged 0.8-76.2% and 86.1-100%, respectively. HBP hypointensity yielded the highest sensitivity but also the lowest specificity and was the only AF remaining independently associated with the diagnosis of HCC at multivariate logistic regression analysis (OR 14.83, 95% CI 5.81-42.76, p < 0.001).

CONCLUSIONS

Among all AFs, HBP hypointensity yields the highest sensitivity for the diagnosis of HCC.

KEY POINTS

• LR-3 and LR-4 observations diagnosed as HCC have a significantly higher number of ancillary features favoring malignancy compared to observations proven to be benign. • The presence of three or more ancillary features favoring malignancy has a high specificity (96.2%) for the diagnosis of HCC. • Among all ancillary features favoring malignancy, hepatobiliary phase hypointensity yields the highest sensitivity, but also the lowest specificity for the diagnosis of HCC.

Indeterminate liver lesions - a virtual epidemic: a cohort study over 8 years

BACKGROUND

Within the last decade, advances and availability in radiological imaging have led to an increase in the detection of incidental liver lesions (ILLs) in the asymptomatic patient population. This poses a diagnostic conundrum. This study was undertaken to review the outcome of liver lesions labelled as 'indeterminate' in asymptomatic patients without a biopsy-proven concomitant primary tumour. The secondary aim was to assess the impact on healthcare resources and cost-effectiveness with regards to the frequency and modality of radiological scans, multidisciplinary team discussions and clinic reviews.

METHODS

The study consisted of a retrospective analysis of prospectively collected data from the University Hospitals of Leicester multidisciplinary team database. The study period ranged from 2010 to 2015. All patients were followed-up for 3 years to ensure no late re-occurrences with malignancy.

RESULTS

A total of 92 patients with ILL were identified. The median age was 72 years. The median size of these ILLs was 10 mm. Eighty-seven patients required supplementary imaging and 42 required a third imaging. Ninety-one patients had benign lesions. Only one case was biopsy proven to be malignant.

CONCLUSION

Small (<15 mm) hepatic lesions discovered incidentally in patients with no known primary malignancy and risk factors are virtually always benign, with a 1% risk of malignancy. There is a need for a classification system, which stratifies ILLs by malignant potential based on a standardized and evidence-based approach. This is important to prevent unnecessary investigations. A multidisciplinary approach in an experienced hepatobiliary and pancreatic centre is recommended until such a classification exists.

Resolution of indeterminate MRI with CEUS in patients at high risk for hepatocellular carcinoma

PURPOSE

To show the contribution of CEUS to characterization of indeterminate MRI observations in high-risk patients for hepatocellular carcinoma (HCC).

METHODS

From July to December 2015, 42 consecutive patients referred to CEUS with indeterminate MRI scans comprise our study cohort. There are 50 indeterminate nodule-like observations and 10 arterial phase hyperenhancing foci, suggesting pseudolesions/arterio-portal shunts. MRI and CEUS lesions are classified according to their enhancement features in all phases and Liver Imaging and Reporting Data System (LI-RADS) in a blind read format. Clinical pathologic correlation and 24 months follow-up are performed.

RESULTS

A majority, 37/50 (74%), of indeterminate nodule-like observations have arterial phase enhancement without washout on MRI. CEUS further characterizes enhancement and shows washout in 14/37 (38%). In total, CEUS diagnoses 16 malignant lesions in 14 patients including 14 HCC and 2 ICC. 12/16 (75%) malignant lesions are confirmed by biopsy or follow-up. Ultrasound identification of a nodule differentiates real nodules from pseudolesions. Of the ten suspected arterial-portal shunts on MRI, two show a real nodule on ultrasound, confirmed as an HCC and a regenerative nodule. 15/42 (36%) patients have LI-RADS escalated from LR-3 or 4 on MRI to LR-4 or 5 on CEUS. Overall, the sensitivity of CEUS is (13/16) 81.3% and specificity is (37/37) 100% for malignant diagnosis.

CONCLUSION

Grayscale ultrasound detects true nodules. Dynamic CEUS detects and characterizes washout, correctly predicting HCC. CEUS is complimentary to MRI and can serve as a problem-solving tool when MRI is indeterminate.

Genome-wide discovery and validation of diagnostic DNA methylation-based biomarkers for hepatocellular cancer detection in circulating cell free DNA

Hepatocellular carcinoma (HCC), the most prevalent form of liver cancer, is growing in incidence but treatment options remain limited, particularly for late stage disease. As liver cirrhosis is the principal risk state for HCC development, markers to detect early HCC within this patient population are urgently needed. Perturbation of epigenetic marks, such as DNA methylation (5mC), is a hallmark of human cancers, including HCC. Identification of regions with consistently altered 5mC levels in circulating cell free DNA (cfDNA) during progression from cirrhosis to HCC could therefore serve as markers for development of minimally-invasive screens of early HCC diagnosis and surveillance.

Methods: To discover DNA methylation derived biomarkers of HCC in the background of liver cirrhosis, we profiled genome-wide 5mC landscapes in patient cfDNA using the Infinium HumanMethylation450k BeadChip Array. We further linked these findings to primary tissue data available from TCGA and other public sources. Using biological and statistical frameworks, we selected CpGs that robustly differentiated cirrhosis from HCC in primary tissue and cfDNA followed by validation in an additional independent cohort.

Results: We identified CpGs that segregate patients with cirrhosis, from patients with HCC within a cirrhotic liver background, through genome-wide analysis of cfDNA 5mC landscapes. Lasso regression analysis pinpointed a panel of probes in our discovery cohort that were validated in two independent datasets. A panel of five CpGs (cg04645914, cg06215569, cg23663760, cg13781744, and cg07610777) yielded area under the receiver operating characteristic (AUROC) curves of 0.9525, 0.9714, and 0.9528 in cfDNA discovery and tissue validation cohorts 1 and 2, respectively. Validation of a 5-marker panel created from combining hypermethylated and hypomethylated CpGs in an independent cfDNA set by bisulfite pyrosequencing yielded an AUROC of 0.956, compared to the discovery AUROC of 0.996.

Conclusion: Our finding that 5mC markers derived from primary tissue did not perform well in cfDNA, compared to those identified directly from cfDNA, reveals potential advantages of starting with cfDNA to discover high performing markers for liquid biopsy development.

Hypo-vascular hepatocellular carcinoma and liver transplantation: Morphological characteristics and implications on outcomes

BACKGROUND

The clinical importance of hypovascular liver lesions in cirrhotic patients awaiting liver transplantation (LT) has not been fully investigated. The objective of this study was to characterize the clinicopathologic features and management of these tumors and to assess their impact on post-LT outcomes.

METHODS

We performed a retrospective review of cirrhotic patients with lesions suspicious for hypovascular hepatocellular carcinoma (HCC) who underwent LT at a single institution from 2011- 2017.

RESULTS

We identified 22 pre-LT patients with radiologic diagnosis of a lesion(s) suspicious for hypovascular HCC. There were 28 hypovascular lesions within the 22 patient cohort; 9 lesions (32%) converted to hypervascular HCC before LT and 19 lesions remained hypovascular at LT. 88% of hypovascular lesions were HCC on explant pathology. Compared to patients with hyper-vascular HCC lesions, hypovascular HCC lesions underwent less preoperative tumor ablation (58% vs 89%; P < .01). Hypovascular HCC were more likely to be well-differentiated (67% vs 11%; P < .01), but there were no differences in the microvascular invasion, tumor recurrence, or survival post-LT.

CONCLUSIONS

Hypovascular HCC has similar clinical outcomes and needs for transplantation as hypervascular HCC. The high prevalence of HCC within suspicious hypovascular lesions supports a similar monitoring and locoregional therapy strategy as for hypervascular HCC.

Liver imaging reporting and data system (LI-RADS) v2018: comparison between computed tomography and gadoxetic acid-enhanced magnetic resonance imaging

PURPOSE

To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI.

MATERIALS AND METHODS

Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images.

RESULTS

Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P < 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P < 0.001) CONCLUSION: The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

Introduction to the Liver Imaging Reporting and Data System for Hepatocellular Carcinoma

The Liver Imaging Reporting And Data System (LI-RADS) was created with the support of the American College of Radiology (ACR) to standardize the acquisition, interpretation, reporting, and data collection for imaging examinations in patients at risk for hepatocellular carcinoma (HCC). A comprehensive and rigorous system developed by radiologists, hepatologists, pathologists, and surgeons, LI-RADS addresses a wide range of imaging contexts. Currently, 4 algorithms are available publicly on the ACR website: ultrasound for HCC surveillance, computed tomography and magnetic resonance imaging for HCC diagnosis and tumor staging, contrast-enhanced ultrasound for HCC diagnosis, and computed tomography/magnetic resonance imaging for treatment response assessment. Each algorithm is supported by a decision tree, categorization table, lexicon, atlas, technical requirements, and reporting and management guidance. Category codes reflecting the relative probability of HCC and malignancy are assigned to imaging-detected liver observations, with emerging evidence suggesting that LI-RADS accurately stratifies HCC and malignancy probabilities. LI-RADS is an evolving system and has been updated and refined iteratively since 2011 based on scientific evidence, expert opinion, and user feedback, with input from the American Association for the Study of Liver Diseases and the Organ Procurement Transplantation Network/United Network for Organ Sharing. Concurrent with its most recent update, LI-RADS was integrated into the American Association for the Study of Liver Diseases HCC guidance released in 2018. We anticipate continued refinement of LI-RADS and progressive adoption by radiologists worldwide, with the eventual goal of culminating in a single unified system for international use.

Longitudinal evolution of CT and MRI LI-RADS v2014 category 1, 2, 3, and 4 observations

OBJECTIVES

This study assesses the risk of progression of Liver Imaging Reporting and Data System (LI-RADS) categories, and the effects of inter-exam changes in modality or radiologist on LI-RADS categorization.

METHODS

Clinical LI-RADS v2014 CT and MRI exams at our institution between January 2014 and September 2017 were retrospectively identified. Untreated LR-1, LR-2, LR-3, and LR-4 observations with at least one follow-up exam were included. Three hundred and seventy-two observations in 214 patients (149 male, 65 female, mean age 61 ± 10 years) were included during the study period (715 exams total). Cumulative incidence curves for progression to malignant LI-RADS categories (LR-5 or LR-M) and to LR-4 or higher were generated for each index category and compared using log-rank tests with a resampling extension. Relationships between inter-exam changes in LI-RADS category and modality or radiologist, adjusted for inter-exam time intervals, were modeled using mixed effect logistic regressions.

RESULTS

Median inter-exam follow-up interval and total follow-up duration were 123 and 227 days, respectively. Index LR-1, LR-2, LR-3, and LR-4 differed significantly in their cumulative incidences of progression to malignant categories (p < 0.0001), which were 0%, 2%, 7%, and 32% at 6 months, respectively. Index LR-1, LR-2, and LR-3 differed significantly in cumulative incidences of progression to LR-4 or higher (p = 0.003). MRI-MRI exam pairs had more stable LI-RADS categorization compared to CT-CT (OR = 0.460, p = 0.0018).

CONCLUSIONS

LI-RADS observations demonstrate increasing risk of progression to malignancy with increasing category ranging from 0% for LR-1 to 32% for LR-4 at 6 months. Inter-exam modality changes are associated with LI-RADS category changes.

KEY POINTS

• While the majority of LR-2 observations remain stable over long-term follow-up, LR-3 and especially LR-4 observations have a higher risk for category progression. • Category transitions between sequential exams using different modalities (CT vs. MRI) may reflect modality differences rather than biological change. MRI, especially with the same type of contrast agent, may provide the most reproducible categorization, although this needs additional validation. • In a clinical practice setting, in which radiologists refer to prior imaging and reports, there was no significant association between changes in radiologist and changes in LI-RADS categorization.

Digital subtract angiography and lipiodol deposits following embolization in cirrhotic nodules of LIRADS category ≥3

PURPOSE

To assess the correlation between Liver Imaging Reporting and Data System (LIRADS) and digital substract angiography (DSA) and lipiodol deposits in cirrhotic nodules of LIRADS category ≥3 receiving interventional treatment.

METHODS

From June 2014 to June 2016, patients with cirrhotic nodules were identified retrospectively and MR images were reviewed by sub-specialty radiologists according to modified LIRADS v2014. Correlation between nodules of LIRADS category ≥3 and DSA findings and lipiodol deposits were analyzed.

RESULTS

71 cirrhotic nodules were evaluated in 33 patients. 39/71 nodules were classified as LR-3, 9/71 nodules were categorized as LR-4, 23/71 nodules were grouped into LR-5. 43 nodules presented positive DSA, 37 nodules showed presence of lipiodol deposits during follow up. With the upgrade of LIRADS category of cirrhotic nodules, DSA and lipiodol deposits became more conspicuous. Spearman analysis demonstrated positive correlations between LIRADS and DSA (r = 0.567, P = 0.000) as well as LIRADS and lipiodol deposits (r = 0.616, P = 0.000). ROC analysis revealed a cut-off value of LR ≥ 4 resulted in a sensitivity of 67.4% and specificity of 89.3% in predicting positive DSA (RUC = 0.799, P ＜ 0.0001), and a sensitivity of 75.7% and specificity of 88.2% in predicting lipiodol deposits (RUC = 0.818, P ＜ 0.0001). Of 39 lesions of LR-3, 64.1% (25/39) showed negative DSA, and 76.9% (30/39) showed absence of lipiodol deposits during follow up. Logistic regression analysis identified arterial enhancement (OR = 26.837, P = 0.002) and lesion size (OR = 1.325, P = 0.022) were independently associated with positive DSA in nodule of LIRADS category ≥3, while no factors were associated with lipiodol deposits.

CONCLUSION

The LIRADS can be used to predict DSA findings and lipiodol deposits in nodules with LIRADS score 3 and above. LIRADS 3 nodules tend to be DSA-negative and have less lipiodol deposits. DSA and lipiodol deposits become more conspicuous in nodules from LIRADS 3 to 5.

Gadoxetic acid-enhanced magnetic resonance imaging: Hepatocellular carcinoma and mimickers

Gadoxetic acid, a hepatocyte-specific magnetic resonance imaging (MRI) contrast agent, has emerged as an important tool for hepatocellular carcinoma (HCC) diagnosis. Gadoxetic acid-enhanced MRI is useful for the evaluation of early-stage HCC, diagnosis of HCC precursor lesions, and highly sensitive diagnosis of HCC. Furthermore, functional information provided by gadoxetic acid-enhanced MRI can aid in the characterization of focal liver lesions. For example, whereas lesions lack functioning hepatocytes appear hypointense in the hepatobiliary phase, preserved or enhanced expression of organic anion transporting polypeptides in some HCCs as well as focal nodular hyperplasia lead to hyperintensity in the hepatobiliary phase; and a targetoid appearance on transitional phase or hepatobiliary phase imaging can be helpful for identifying the histopathological composition of tumors. While gadoxetic acid-enhanced MRI may improve the sensitivity of HCC diagnosis and provide new insights into the characterization of focal liver lesions, there are many challenges associated with its use. This article reviews the pros and cons of HCC diagnosis with gadoxetic acid-enhanced MRI and discuss some clues in the radiological differentiation of HCC from HCC mimickers.

Gadoxetic acid-enhanced MRI of transient hepatic enhancement differences: Another cause of hypointense observation on hepatobiliary phase

PURPOSE

To retrospectively determine the frequency, natural history and factors associated with the presence of transient hepatic enhancement difference showing hypointensity on hepatobiliary phase images of gadoxetic acid-enhanced MRI.

MATERIALS AND METHODS

Gadoxetic acid-enhanced MRI of 125 patients (91 men; 34 women) with transient hepatic enhancement difference were retrospectively reviewed. Three readers qualitatively and quantitatively evaluated MR imaging features and evolution at follow up. The Chi-square test, Fisher's exact test and Kruskall-Wallis rank test were used for statistical analysis.

RESULTS

Transient hepatic enhancement difference were hypointense on hepatobiliary phase images in 20 of 125 cases (16%). At univariate analysis there was association with wedge-shape morphology (p < 0.001), size ≥21 mm (p < 0.001), hyperintensity on T2-weighted imaging (p < 0.001), restricted diffusion (p < 0.001) and previous treatment (p < 0.005). At multivariate analysis, the following factors were associated: previous treatment (p < 0.05), hyperintensity on T2-weighted imaging (p < 0.001) and size ≥21 mm (p < 0.001). Of 12 patients with hypointense transient hepatic enhancement difference on hepatobiliary phase images who had follow-up MRI, nine showed reduction in size.

CONCLUSION

Transient hepatic enhancement difference observations showing hypointensity on hepatobiliary phase images of gadoxetic acid-enhanced MRI are not infrequent and may shrink at follow-up. They are more likely associated with size ≥21 mm, hyperintensity on T2-weighted images and previous treatment of adjacent tumor.

Role of Imaging in Surveillance and Diagnosis of Hepatocellular Carcinoma

The prognosis for hepatocellular carcinoma (HCC) is dependent on tumor stage at diagnosis, with curative treatment options more available to early-detected HCCs. Professional organizations have produced HCC screening guidelines in at-risk groups, with ultrasound the most commonly used screening tool and increased interest in MRI in specific populations. HCC may be diagnosed by imaging features alone and have been universally incorporated into management guidelines. The radiology community has standardized imaging criteria for HCC with the development of the Liver Imaging Reporting and Data System, which has expanded to incorporate computed tomography, MR, and contrast-enhanced ultrasound for diagnostic purposes.

Comparison of LI-RADS v.2017 and ESGAR Guidelines Imaging Criteria in HCC Diagnosis Using MRI with Hepatobiliary Contrast Agents

Purpose

The purpose of this study was to assess and compare diagnostic ability of LI-RADS (LR) v. 2017 and ESGAR guidelines in hepatocellular carcinoma (HCC) diagnosis using MRI with hepatobiliary contrast agents.

Methods

Seventy pathologically confirmed lesions in 32 patients (24 males and 8 females) who had MRI with hepatobiliary contrast done before surgery or biopsy were reviewed retrospectively. Six lesions were <10mm, 31 lesions 10-19mm, and 33 lesions ≥20mm. Two readers assessed all lesions according to LI-RADS v.2017 criteria and ESGAR consensus statement on liver MR imaging and clinical use of liver-specific contrast agents. Statistical analysis was performed to compare diagnostic ability of both guidelines including receiver operative curves (ROC) and area under curve (AUC).

Results

For LR ≥ 4 sensitivity, specificity, accuracy, and AUC were 96%, 75%, 88.6%, and 85.5, respectively. For LR5 they were 74%, 95%, 80%, and 84.5, respectively. For ESGAR criteria with major and additional features, they were 88%, 75%, 84.3%, and 81.5, respectively. For ESGAR criteria only with major features they were 78%, 80%, 78.6%, and 79, respectively. AUC analysis revealed that overall diagnostic ability of LI-RADS was higher than ESGAR but the results did not show statistical significance.

Conclusions

Both LI-RADS and ESGAR guidelines presented high diagnostic ability in HCC diagnosis of MRI studies with hepatobiliary contrast agents. More complex LI-RADS criteria performed better than ESGAR guidelines and it may justify extra effort that needs to be put in the report. However, the results were not statistically different and the simplicity of the ESGAR guidelines should also be taken into consideration.

LI-RADS v2017 for liver nodules: how we read and report

The Liver Imaging Reporting and Data System (LI-RADS) standardizes the interpretation and reporting of imaging examinations in patients at risk for hepatocellular carcinoma (HCC). For focal liver observations it assigns categories (LR-1 to 5, LR-M, LR-TIV), which reflect the relative probability of benignity or malignancy of the respective observation. The categories assigned are based on major and ancillary image features, which have been developed by the American College of Radiology (ACR) and validated in many studies. This review summarizes the relevant CT and MRI features and presents an image-guided approach for readers not familiar with LI-RADS on how to use the system. The widespread adoption of LI-RADS for reporting would help reduce inter-reader variability and improve communication among radiologists, hepatologists, hepatic surgeons and oncologists, thus leading to improved patient management.

LI-RADS for MR Imaging Diagnosis of Hepatocellular Carcinoma: Performance of Major and Ancillary Features

Purpose To evaluate the performance of major features, ancillary features, and categories of Liver Imaging Reporting and Data System (LI-RADS) version 2014 at magnetic resonance (MR) imaging for the diagnosis of hepatocellular carcinoma (HCC). Materials and Methods This retrospective institutional review board-approved study included patients with liver MR imaging and at least one pathologically proved lesion. Between 2004 and 2016, 102 patients (275 observations including 113 HCCs) met inclusion criteria. Two radiologists independently assessed major and ancillary imaging features for each liver observation and assigned a LI-RADS category. Per-lesion estimates of diagnostic performance of major features, ancillary features, and LI-RADS categories were assessed by using generalized estimating equation models. Results Major features (arterial phase hyperenhancement, washout, capsule, and threshold growth) had a sensitivity of 88.5%, 60.6%, 32.9%, and 41.6%, and a specificity of 18.6%, 84.8%, 98.8%, and 83.2% for HCC, respectively. Ancillary features (mild-moderate T2 hyperintensity, restricted diffusion, mosaic architecture, intralesional fat, lesional fat sparing, blood products, and subthreshold growth) had a sensitivity of 62.2%, 54.8%, 9.9%, 30.9%, 23.1%, 2.8%, and 48.3%, and a specificity of 79.4%, 90.6%, 99.4%, 94.2%, 83.1%, 99.3%, and 91.4% for HCC, respectively. The LR-5 or LR-5 V categories had a per-lesion sensitivity of 50.8% and a specificity of 95.8% for HCC, respectively. The LR-4, LR-5, or LR-5 V categories (determined by using major features only vs combination of major and ancillary features) had a per-lesion sensitivity of 75.9% and 87.9% and a per-lesion specificity of 87.5% and 86.2%, respectively. Conclusion The use of ancillary features in combination with major features increases the sensitivity while preserving a high specificity for the diagnosis of HCC.

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

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

CEUS LI-RADS: algorithm, implementation, and key differences from CT/MRI

Contrast-enhanced ultrasound (CEUS) is a specialized form of ultrasound (US) performed with an intravenous injection of microbubble contrast agents. It has been successfully used for a variety of applications including characterization of liver tumors. In April 2014, the American College of Radiology (ACR) convened a working group of international experts to develop ACR CEUS Liver Imaging Reporting and Data System (CEUS LI-RADS). An initial version of CEUS LI-RADS was published in August 2016. Although the CEUS LI-RADS concept and principles for liver lesion characterization, using dynamic contrast enhancement features, are similar to those for CT or MRI, there are significant differences between CT/MRI and CEUS LI-RADS. Therefore, CEUS LI-RADS has different diagnostic features and a unique characterization algorithm. The size of a lesion, the type and degree of arterial phase enhancement, the presence of washout, and the timing and degree of washout are the major features used for categorization. This paper describes key differences between CT/MRI and CEUS, and provides a diagnostic algorithm of CEUS LI-RADS with detailed, step-by-step instructions and imaging examples of CEUS LI-RADS categories.

Management implications and outcomes of LI-RADS-2, -3, -4, and -M category observations

A radiologist issuing a LI-RADS category is, implicitly or explicitly, a member of a multidisciplinary team. If the definite diagnosis of a benign or malignant entity is not possible, categorizing the uncertainty as LR-2, -3, -4, or -M has important management implications. In this article, we discuss the range of options for management or further diagnostic testing and how a LR category may affect the choice between them. We then review recent published data regarding eventual diagnoses following assignment of a LR category.

Interreader Reliability of LI-RADS Version 2014 Algorithm and Imaging Features for Diagnosis of Hepatocellular Carcinoma: A Large International Multireader Study

Purpose To determine in a large multicenter multireader setting the interreader reliability of Liver Imaging Reporting and Data System (LI-RADS) version 2014 categories, the major imaging features seen with computed tomography (CT) and magnetic resonance (MR) imaging, and the potential effect of reader demographics on agreement with a preselected nonconsecutive image set. Materials and Methods Institutional review board approval was obtained, and patient consent was waived for this retrospective study. Ten image sets, comprising 38-40 unique studies (equal number of CT and MR imaging studies, uniformly distributed LI-RADS categories), were randomly allocated to readers. Images were acquired in unenhanced and standard contrast material-enhanced phases, with observation diameter and growth data provided. Readers completed a demographic survey, assigned LI-RADS version 2014 categories, and assessed major features. Intraclass correlation coefficient (ICC) assessed with mixed-model regression analyses was the metric for interreader reliability of assigning categories and major features. Results A total of 113 readers evaluated 380 image sets. ICC of final LI-RADS category assignment was 0.67 (95% confidence interval [CI]: 0.61, 0.71) for CT and 0.73 (95% CI: 0.68, 0.77) for MR imaging. ICC was 0.87 (95% CI: 0.84, 0.90) for arterial phase hyperenhancement, 0.85 (95% CI: 0.81, 0.88) for washout appearance, and 0.84 (95% CI: 0.80, 0.87) for capsule appearance. ICC was not significantly affected by liver expertise, LI-RADS familiarity, or years of postresidency practice (ICC range, 0.69-0.70; ICC difference, 0.003-0.01 [95% CI: -0.003 to -0.01, 0.004-0.02]. ICC was borderline higher for private practice readers than for academic readers (ICC difference, 0.009; 95% CI: 0.000, 0.021). Conclusion ICC is good for final LI-RADS categorization and high for major feature characterization, with minimal reader demographic effect. Of note, our results using selected image sets from nonconsecutive examinations are not necessarily comparable with those of prior studies that used consecutive examination series. ^© RSNA, 2017.

Diagnostic efficacy of the Liver Imaging-Reporting and Data System (LI-RADS) with CT imaging in categorising small nodules (10-20 mm) detected in the cirrhotic liver at screening ultrasound

AIM

To estimate the diagnostic accuracy of the Liver Imaging-Reporting and Data System (LI-RADS) with computed tomography (CT) for diagnosing hepatic nodules (10-20 mm) detected in cirrhotic livers.

MATERIALS AND METHODS

Fifty-five patients with liver cirrhosis and a solitary nodule (10-20 mm in diameter) detected via ultrasound surveillance, underwent hepatic CT and fine-needle biopsy. All the CT images were analysed and the lesions were categorised into five categories according to the LI-RADS.

RESULTS

Final diagnoses of the 55 nodules were as follows: 34 hepatocellular carcinomas (HCCs), one intrahepatic cholangiocarcinomas, one adrenocortical carcinoma metastasis, and 19 benign lesions. None (0%) of four LI-RADS category 1 lesions, two (22%) of nine category 2 lesions, seven (50%) of 14 category 3 lesions, two (67%) of three category 4 lesions, 22 (96%) of 23 category 5 lesions and one (50%) of two lesions classified as other malignancies was HCC. One category 5 lesion was adrenocortical carcinoma metastasis and one of two lesions categorised as other malignancies was intrahepatic cholangiocarcinoma. In patients with nodules detected at surveillance ultrasound, the best threshold for confident HCC diagnosis was more than LI-RADS category 3. The use of this threshold produced a sensitivity and specificity of 72.7% and 90%, respectively. So combining LI-RADS 4 and 5 categories for confident HCC diagnosis would improve accuracy and sensitivity with no significant impairment of specificity or positive predictive value.

CONCLUSION

LIRADS with CT provides a strong validity for the diagnosis of small hepatic nodules, and is very useful to improve the accuracy of CT reports.

Natural history of liver imaging reporting and data system category 4 nodules in MRI

PURPOSE

The purpose of this study was to characterize the MR imaging features and outcomes of liver imaging reporting and data system (LI-RADS) category 4 (LR4) nodules, with an emphasis on upgrade to category 5 (LR5) and development of contraindications to curative therapy.

METHODS

Institutional review board approval was obtained for this retrospective, dual-institutional Health Insurance Portability and Accountability Act-compliant study. The requirement for informed consent was waived. Contrast-enhanced MRI studies performed on patients with cirrhosis were retrospectively assessed using LI-RADS 2014 by at least two readers. All nodules were individually evaluated to determine their major imaging features at diagnosis, and follow-up data were used to determine the associated imaging outcomes.

RESULTS

One hundred eighty-one untreated LR4 nodules in 139 patients had adequate imaging and follow-up for inclusion in the study. Most (61% [111/181]) of these demonstrated arterial phase hyperenhancement, washout, and diameter less than 20 mm. During the follow-up period (median 163 days), 31% (56/181) of the nodules upgraded to LR5, 40% (73/181) remained stable, and 29% (52/181) downgraded. Of the nodules that upgraded, 61% (34/56) increased their size category and 54% (30/56) developed newly visualized capsules. No LR4 nodules developed venous invasion, satellites nodules, or new intrahepatic or extrahepatic metastatic disease. 75% (42/56) of the nodules that upgraded to LR5 did so within 6 months.

CONCLUSIONS

Approximately one-third of LR4 nodules upgrade to LR5, and the short-term risk of developing venous invasion or metastasis is very low.

Differences in Liver Imaging and Reporting Data System Categorization Between MRI and CT

OBJECTIVE

The purpose of this study is to determine whether focal liver observations are categorized differently by CT and MRI using the Liver Imaging and Reporting Data System (LI-RADS).

MATERIALS AND METHODS

We performed a retrospective review of 58 patients at risk for hepatocellular carcinoma who underwent liver protocol CT and MRI within 1 month of each other. Two readers assigned a LI-RADS category for all focal liver observations in consensus. A significant category upgrade was defined as a change from LI-RADS categories 1 and 2 or nonvisualization to LI-RADS categories 3-5, from LI-RADS category 3 to category 4 or 5, from LI-RADS category 4 to category 5, or from any category to LI-RADS category 5V. A significant downgrade was defined as a change from LI-RADS category 5 to categories 1-4, from LI-RADS category 4 to categories 1-3, or from LI-RADS category 3 to categories 1 or 2.

RESULTS

The LI-RADS category was different between CT and MRI for 77.2% (176/228) of observations. A significant upgrade occurred on MRI for 42.5% (97/228) of observations because of nonvisualization by CT (n = 78), capsule (n = 8), arterial hyperenhancement (n = 4), intratumoral fat (n = 2), larger size (n = 2), tumor in portal vein (n = 2), and wash-out (n = 1). Of these 97 upgraded observations, two were upgraded to LI-RADS category 5V, 15 were upgraded to category 5, and 13 were upgraded to category 4. A significant downgrade occurred on MRI for 8.8% (20/228) of observations because of marked T2 hyperintensity (n = 14), smaller size (n = 2), wedge shape (n = 2), and marked T2 hypointensity (n = 2).

CONCLUSION

LI-RADS categorization of focal liver observations is dependent on imaging modality. MRI results in both upgraded and downgraded categorization compared with CT in an important proportion of observations.

Imaging Outcomes of Liver Imaging Reporting and Data System Version 2014 Category 2, 3, and 4 Observations Detected at CT and MR Imaging

Purpose To determine the proportion of untreated Liver Imaging Reporting and Data System (LI-RADS) version 2014 category 2, 3, and 4 observations that progress, remain stable, or decrease in category and to compare the cumulative incidence of progression in category. Materials and Methods In this retrospective, longitudinal, single-center, HIPAA-compliant, institutional review board-approved study, 157 patients (86 men and 71 women; mean age ± standard deviation, 59.0 years ± 9.7) underwent two or more multiphasic computed tomographic (CT) or magnetic resonance (MR) imaging examinations for hepatocellular carcinoma surveillance, with the first examination in 2011 or 2012. One radiologist reviewed baseline and follow-up CT and MR images (mean follow-up, 614 days). LI-RADS categories issued in the clinical reports by using version 1.0 or version 2013 were converted to version 2014 retrospectively; category modifications were verified with another radiologist. For index category LR-2, LR-3, and LR-4 observations, the proportions that progressed, remained stable, or decreased in category were calculated. Cumulative incidence curves for progression were compared according to baseline LI-RADS category (by using log-rank tests). Results All 63 index LR-2 observations remained stable or decreased in category. Among 166 index LR-3 observations, seven (4%) progressed to LR-5, and eight (5%) progressed to LR-4. Among 52 index LR-4 observations, 20 (38%) progressed to a malignant category. The cumulative incidence of progression to a malignant category was higher for index LR-4 observations than for index LR-3 or LR-2 observations (each P < .001) but was not different between LR-3 and LR-2 observations (P = .155). The cumulative incidence of progression to at least category LR-4 was trend-level higher for index LR-3 observations than for LR-2 observations (P = .0502). Conclusion Observations classified according to LI-RADS version 2014 categories are associated with different imaging outcomes. (©) RSNA, 2016 Online supplemental material is available for this article.

Classifying CT/MR findings in patients with suspicion of hepatocellular carcinoma: Comparison of liver imaging reporting and data system and criteria-free Likert scale reporting models

PURPOSE

To compare the Liver Imaging Reporting and Data System (LI-RADS) and a criteria-free Likert scale (LS) reporting models for classifying computed tomography/magnetic resonance imaging (CT/MR) findings of suspicious hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Imaging data of 281 hepatic nodules in 203 patients were retrospectively included. Imaging characteristics including diameter, arterial hyperenhancement, washout, and capsule were reviewed independently by two groups of readers using LI-RADS and LS (range, score 1-5). LS is primarily based on the overall impression of image findings without using fixed criteria. Interreader agreement (IRA), intraclass agreement (ICA), and diagnostic performance were determined by Fleiss, Cohen's kappa (κ), and logistic regression, respectively.

RESULTS

There were 167 contrast-enhanced CT (CECT) versus 114 MR data. Overall, IRA was moderate (κ = 0.47, 0.52); IRA was moderate-to-good for arterial hyperenhancement, washout, and capsule (κ = 0.56-0.69); excellent for diameter and tumor embolus (κ = 0.99). Overall, ICA between LI-RADS and LS was moderate (κ = 0.44-0.50); ICA was good for scores 1-2 (κ = 0.71-0.90), moderate for scores 3 and 5 (κ = 0.41-0.52), but very poor for score 4 (κ = 0.11-0.19). LI-RADS produced significantly lower accuracy (78.6% vs. 87.2%) and sensitivity (72.1% vs. 92.8%), higher specificity (97.3% vs. 71.2%) and positive likelihood ratio (+LR: 26.32 vs. 3.23) in diagnosis of HCC. CECT produced relatively low IRA, ICA, and diagnostic ability against MR.

CONCLUSION

There were substantial variations in liver observations between LI-RADS and LS. Further study is needed to investigate ICA between CECT and MR.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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