Liver imaging reporting and data system category 4 observations in MRI: Risk factors predicting upgrade to category 5

Up-to-Date Role of Liver Imaging Reporting and Data System in Hepatocellular Carcinoma

This article overviews Liver Imaging Reporting and Data System (LI-RADS), a system that standardizes techniques, interpretation and reporting of imaging studies done for hepatocellular carcinoma surveillance, diagnosis, and locoregional treatment response assessment. LI-RADS includes 4 algorithms, each of which defines ordinal categories reflecting probability of the assessed outcome. The categories, in turn, guide patient management. The LI-RADS diagnostic algorithms provide diagnostic criteria for the entire spectrum of lesions found in at-risk patients. In addition, the use of LI-RADS in clinical care improves clarity of communication between radiologists and clinicians and may improve the performance of inexperienced users to the levels of expert liver imagers.

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.

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.

LI-RADS: Looking Back, Looking Forward

Since its initial release in 2011, the Liver Imaging Reporting and Data System (LI-RADS) has evolved and expanded in scope. It started as a single algorithm for hepatocellular carcinoma (HCC) diagnosis with CT or MRI with extracellular contrast agents and has grown into a multialgorithm network covering all major liver imaging modalities and contexts of use. Furthermore, it has developed its own lexicon, report templates, and supplementary materials. This article highlights the major achievements of LI-RADS in the past 11 years, including adoption in clinical care and research across the globe, and complete unification of HCC diagnostic systems in the United States. Additionally, the authors discuss current gaps in knowledge, which include challenges in surveillance, diagnostic population definition, perceived complexity, limited sensitivity of LR-5 (definite HCC) category, management implications of indeterminate observations, challenges in reporting, and treatment response assessment following radiation-based therapies and systemic treatments. Finally, the authors discuss future directions, which will focus on mitigating the current challenges and incorporating advanced technologies. Tha authors envision that LI-RADS will ultimately transform into a probability-based system for diagnosis and prognostication of liver cancers that will integrate patient characteristics and quantitative imaging features, while accounting for imaging modality and contrast agent.

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.

LR-3 and LR-4 Lesions Are More Likely to Be Hepatocellular Carcinoma in Transplant Patients with LR-5 or LR-TR Lesions

BACKGROUND

Liver Imaging Reporting and Data System (LI-RADS) classifies liver nodules from LR-1 to LR-5 based on risk for hepatocellular carcinoma (HCC). It is challenging to know the nature of the LR-3 and LR-4 lesions.

AIMS

To test our hypothesis that in patients with a definite HCC (LR-5) or treated HCC (LR-TR), a coexisting LR-3 or LR-4 lesion is more likely to represent HCC compared to patients without LR-5 or LR-TR lesions.

METHODS

We conducted a retrospective study including all adult patients who received liver transplantation in our institution from 1/1/2014 to 3/3/2020 who had any LR-3 or LR-4 lesion on pre-transplant MRI.

RESULTS

Seventy-eight patients were included in the final cohort (115 LR-3 and LR-4 lesions total). When accompanied by LR-5 or LR-TR lesions, 41% (28/69) of LR-3 lesions were HCC compared to 12% (3/25) when not accompanied by LR-5 LR-TR lesions. When accompanied by LR-5 or LR-TR lesions, 83% (10/12) of LR-4 lesions were HCC, versus 33% (3/9) when not accompanied by LR-5 or LR-TR lesions. In a multivariable analysis of all lesions, the presence of a LR-5 or LR-TR lesion was significantly associated with LR-3 or LR-4 lesions representing HCC (OR 6.4, p = 0.01).

CONCLUSION

LR-3 and LR-4 lesions are more likely to be HCC in patients with LR-5 or LR-TR lesions. The presence of coexisting definite HCC may be a useful diagnostic feature to improve risk stratification of lesions without typical imaging features of HCC. This may also affect decision-making prior to liver transplant when HCC burden must be accurately determined.

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.

Clinical Outcomes of Patients with Suspicious (LI-RADS 4) Liver Observations

Hepatocellular cancer (HCC) surveillance is associated with increased curative treatment and improved survival, underscoring its importance in patients with cirrhosis.¹ Surveillance is 1 step in a larger HCC screening continuum, and those with abnormal screening results must undergo diagnostic evaluation with multiphase computed tomography (CT) or magnetic resonance imaging (MRI).² The Liver Imaging Reporting and Data System (LI-RADS) classifies liver observations in at-risk patients based on risk of malignancy and HCC, with LR-5 observations having a positive predictive value exceeding 95% for HCC. However, indeterminate liver nodules (ie, LR-3 or LR-4) are commonly observed in clinical practice, associated with heterogenous HCC risk, and have large variations in practice management.^3,4 We previously reported the natural history of LR-3 observations in a multicenter cohort of patients with cirrhosis, demonstrating a high annual incidence for HCC development of 8.4 cases per 100 person-years;⁵ however, the natural history of LR-4 observations remains uncertain. Herein, we aimed to characterize clinical outcomes in patients with LR-4 observations in a multicenter cohort.

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.

Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein improves diagnostic accuracy for hepatocellular carcinoma

BACKGROUND

Diagnostic accuracy of various tumor markers and their combinations for hepatocellular carcinoma (HCC) was not fully investigated.

AIM

To evaluate the diagnostic accuracy of alpha-fetoprotein (AFP), the Lens culinaris agglutinin-reactive fraction of AFP (AFP-L3), and protein induced by vitamin K absence or antagonist-II (PIVKA-II) and their combination for HCC diagnosis.

METHODS

Patients with newly detected liver mass or elevated serum AFP levels were considered eligible. Serum AFP level, AFP-L3 fraction, and PIVKA-II level were measured at the first visit.

RESULTS

In total, 622 patients were included; 355 patients (57.1%) had chronic liver disease, and 208 (33.4%) had liver cirrhosis. HCC was diagnosed in 160 patients (25.7%). The area under the receiver operating characteristics curves (AUROCs) of the serum AFP, AFP-L3 fraction, AFP-L3, and PIVKA-II levels for the diagnosis of HCC were 0.775, 0.792, 0.814, and 0.834, respectively. A novel diagnostic model was developed by classifying patients in a 1:1 ratio into training and validation sets. Using the binary regression analysis of the training cohort, the AFP, AFP-L3 fraction, and PIVKA-II (ALPs) score was calculated as follows: ALPs score = 3.8 × [serum AFP level (ng/mL) × AFP-L3 fraction (%) × 0.01] + 0.2 × PIVKA-II level (mAU/mL). The AUROC of the ALPs score for diagnosis of HCC was 0.878, significantly higher than that of serum AFP level (P < 0.001), AFP-L3 fraction (P < 0.001), PIVKA-II level (P = 0.036), and AFP-L3 level (P = 0.006). The optimal ALPs score cut-off was 5.3 (sensitivity, 85.0%, specificity 80.1%). The validation cohort showed similar results.

CONCLUSION

The ALPs score calculated using serum AFP level, AFP-L3 fraction, and PIVKA-II level showed improved accuracy in HCC diagnosis.

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.

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 (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.

Characterization of liver nodules in patients with chronic liver disease by MRI: performance of the Liver Imaging Reporting and Data System (LI-RADS v.2018) scale and its comparison with the Likert scale

OBJECTIVES

To evaluate the performance of the LI-RADS v.2018 scale by comparing it with the Likert scale, in the characterization of liver lesions.

METHODS

A total of 39 patients with chronic liver disease underwent MR examination for characterization of 44 liver lesions. Images were independently analyzed by two radiologists using the LI-RADS scale and by another two radiologists using the Likert scale. The reference standard used was either histopathological evaluation or a 4-year MRI follow-up. Receiver operating characteristic analysis was performed.

RESULTS

The LI-RADS scale obtained an accuracy of 80%, a sensitivity of 72%, a specificity of 93%, a positive predictive value (PPV) of 93% and a negative predictive value (NPV) of 70%, while the Likert scale achieved an accuracy of 79%, a sensitivity of 73%, a specificity of 87%, a PPV of 89% and a NPV of 70%. The area under the curve (AUC) was 85% for the LI-RADS scale and 83% for the Likert scale. The inter-observer agreement was strong (k = 0.89) between the LI-RADS evaluators and moderate (k = 0.69) between the Likert evaluators.

CONCLUSIONS

There was no statistically significant difference between the performances of the two scales; nevertheless, we suggest that the LI-RADS scale be used, as it appeared more objective and consistent.

Predictors and Cumulative Frequency of Hepatocellular Carcinoma in High and Intermediate LI-RADS Lesions: A Cohort Study from a Canadian Academic Institution

BACKGROUND

The frequency and predictors of hepatocellular carcinoma (HCC) within each liver imaging reporting and data system (LI-RADS) category remains unclear. We sought to estimate the cumulative frequency of HCC in LI-RADS observations of high/intermediate category and identify clinical/radiographic features associated with HCC.

METHODS

Our diagnostic imaging database was searched for computed tomography/magnetic resonance imaging reports of patients with evidence of cirrhosis and liver observations. LI-RADS categories were determined by imaging review, while demographic and clinical outcomes were assigned by chart review. A composite outcome of clinical/radiographic confirmation of HCC was used. We used multivariable analysis to identify features associated with HCC, and competing risks regression to estimate the cumulative frequency of HCC in each category.

RESULTS

Our search returned 95 patients with 137 observations (LR2 = 4, LR3 = 53, LR4 = 37, and LR5 = 43). On multivariable analysis, increasing age (hazard ratio [HR] 1.76 per 10 years, p = 0.049), washout (HR 5.34, p < 0.002), and increasing size (size < 10 mm reference, 10-20 mm, HR 3.93, p = 0.014; size > 20 mm, HR 21.69, p < 0.001) were associated with HCC. Median time to diagnosis was 6.13 months (interquartile range [IQR] 4.6-13.1), 4.7 months (IQR 2.5-14.5), and 3.6 months (IQR 1.9-6.6) for LR3, 4, and 5 category observations, respectively. The cumulative frequency of HCC was 59.8% in LR3, 84.62% in LR4, and 99.84% in LR5, at last follow-up.

CONCLUSION

The frequency of HCC within each LI-RADS category reflects the intended purpose, intermediate probability for LR3, probable HCC for LR4, and definite HCC for LR5.

Accuracy of the Liver Imaging Reporting and Data System in Computed Tomography and Magnetic Resonance Image Analysis of Hepatocellular Carcinoma or Overall Malignancy-A Systematic Review

BACKGROUND & AIMS

The Liver Imaging Reporting and Data System (LI-RADS) categorizes observations from imaging analyses of high-risk patients based on the level of suspicion for hepatocellular carcinoma (HCC) and overall malignancy. The categories range from definitely benign (LR-1) to definitely HCC (LR-5), malignancy (LR-M), or tumor in vein (LR-TIV) based on findings from computed tomography or magnetic resonance imaging. However, the actual percentage of HCC and overall malignancy within each LI-RADS category is not known. We performed a systematic review to determine the percentage of observations in each LI-RADS category for computed tomography and magnetic resonance imaging that are HCCs or malignancies.

METHODS

We searched the MEDLINE, Embase, Cochrane CENTRAL, and Scopus databases from 2014 through 2018 for studies that reported the percentage of observations in each LI-RADS v2014 and v2017 category that were confirmed as HCCs or other malignancies based on pathology, follow-up imaging analyses, or response to treatment (reference standard). Data were assessed on a per-observation basis. Random-effects models were used to determine the pooled percentages of HCC and overall malignancy for each LI-RADS category. Differences between categories were compared by analysis of variance of logit-transformed percentage of HCC and overall malignancy. Risk of bias and concerns about applicability were assessed with the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Of 454 studies identified, 17 (all retrospective studies) were included in the final analysis, consisting of 2760 patients, 3556 observations, and 2482 HCCs. The pooled percentages of observations confirmed as HCC and overall malignancy, respectively, were 94% (95% confidence interval [CI] 92%-96%) and 97% (95% CI 95%-99%) for LR-5, 74% (95% CI 67%-80%) and 80% (95% CI 75%-85%) for LR-4, 38% (95% CI 31%-45%) and 40% (95% CI 31%-50%) for LR-3, 13% (95% CI 8%-22%) and 14% (95% CI 9%-21%) for LR-2, 79% (95% CI 63%-89%) and 92% (95% CI 77%-98%) for LR-TIV, and 36% (95% CI 26%-48%) and 93% (95% CI 87%-97%) for LR-M. No malignancies were found in the LR-1 group. The percentage of HCCs and overall malignancies confirmed differed significantly among LR groups 2-5 (P < .00001). Patient selection was the most frequent factor that affected bias risk, because of verification bias and case-control study design.

CONCLUSIONS

In a systematic review, we found that increasing LI-RADS categories contained increasing percentages of HCCs and overall malignancy based on reference standard confirmation. Of observations categorized as LR-M, 93% were malignancies and 36% were confirmed as HCCs. The percentage of HCCs found in the LR-2 and LR-3 categories indicate the need for a more active management strategy than currently recommended. Prospective studies are needed to validate these findings. PROSPERO number CRD42018087441.

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.

Comparison of international guidelines for noninvasive diagnosis of hepatocellular carcinoma: 2018 update

The goal of this review is to present the similarities and differences among the latest guidelines for noninvasive diagnosis of hepatocellular carcinoma (HCC) of American Association for the Study of Liver Disease (AASLD), European Association for the Study of the Liver (EASL), Liver Imaging Reporting and Data System (LI-RADS), Asian Pacific Association for the Study of the Liver (APASL), and Korean Liver Cancer Association-National Cancer Center (KLCA-NCC) of Korea. In 2018, major guideline updates have been proposed by the AASLD, EASL and KLCA-NCC; AASLD newly incorporated LI-RADS into their HCC diagnostic algorithm. The AASLD and EASL guidelines now include magnetic resonance imaging (MRI) using hepatobiliary contrast media as a first-line diagnostic test in addition to dynamic computed tomography and MRI using extracellular contrast media and the KLCA-NCC and EASL guidelines also include contrast-enhanced ultrasound as a second-line diagnostic test. We will comprehensively review the HCC surveillance and diagnostic algorithms and compare and highlight key features for each guideline. We also address limitations of current systems for the noninvasive diagnosis of HCC.

Joint Consensus Statement of the Indian National Association for Study of the Liver and Indian Radiological and Imaging Association for the Diagnosis and Imaging of Hepatocellular Carcinoma Incorporating Liver Imaging Reporting and Data System

Hepatocellular carcinoma (HCC) is the 6th most common cancer and the second most common cause of cancer-related mortality worldwide. There are currently no universally accepted practice guidelines for the diagnosis of HCC on imaging owing to the regional differences in epidemiology, target population, diagnostic imaging modalities, and staging and transplant eligibility. Currently available regional and national guidelines include those from the American Association for the Study of Liver Disease (AASLD), the European Association for the Study of the Liver (EASL), the Asian Pacific Association for the Study of the Liver, the Japan Society of Hepatology, the Korean Liver Cancer Study Group, Hong Kong, and the National Comprehensive Cancer Network in the United States. India with its large population and a diverse health infrastructure faces challenges unique to its population in diagnosing HCC. Recently, American Association have introduced a Liver Imaging Reporting and Data System (LIRADS, version 2017, 2018) as an attempt to standardize the acquisition, interpretation, and reporting of liver lesions on imaging and hence improve the coherence between radiologists and clinicians and provide guidance for the management of HCC. The aim of the present consensus was to find a common ground in reporting and interpreting liver lesions pertaining to HCC on imaging keeping LIRADSv2018 in mind.

LI-RADS 2017: An update

The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging Reporting & Data System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:1459-1474.

Magnetic resonance imaging ancillary features used in Liver Imaging Reporting and Data System: An illustrative review

Hepatocellular carcinoma (HCC) usually develops in the setting of chronic liver disease. In the adequate clinical context, both multiphasic contrast-enhanced CT and magnetic resonance imaging are non-invasive modalities that allow accurate diagnosis and staging of HCC, although the latter demonstrates greater sensitivity and specificity. Imaging criteria for HCC diagnosis rely on hemodynamic features such as hyperenhancement in the arterial phase and washout in the portal or equilibrium phase. However, imaging performance drops considerably for small (< 20 mm) nodules because their tendency to exhibit atypical enhancement patterns. In order to improve accuracy in the diagnosis and staging of HCC, particularly in cases of atypical nodules, ancillary features, i.e., imaging characteristics that modify the likelihood of HCC, have been described and incorporated into clinical reports, especially in Liver Imaging Reporting and Data System. In this paper, ancillary imaging features will be reviewed and illustrated.

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.

Major and ancillary magnetic resonance features of LI-RADS to assess HCC: an overview and update

Liver Imaging Reporting and Data System (LI-RADS) is a system for interpreting and reporting of imaging features on multidetector computed tomography (MDCT) and magnetic resonance (MR) studies in patients at risk for hepatocellular carcinoma (HCC). American College of Radiology (ACR) sustained the spread of LI-RADS to homogenizing the interpreting and reporting data of HCC patients. Diagnosis of HCC is due to the presence of major imaging features. Major features are imaging data used to categorize LI-RADS-3, LI-RADS-4, and LI-RADS-5 and include arterial-phase hyperenhancement, tumor diameter, washout appearance, capsule appearance and threshold growth. Ancillary are features that can be used to modify the LI-RADS classification. Ancillary features supporting malignancy (diffusion restriction, moderate T2 hyperintensity, T1 hypointensity on hapatospecifc phase) can be used to upgrade category by one or more categories, but not beyond LI-RADS-4. Our purpose is reporting an overview and update of major and ancillary MR imaging features in assessment of HCC.