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

Value of magnetic resonance imaging for diagnosis of LR‑3 and LR-4 lesions coexisting with hepatocellular carcinoma

PURPOSE

To explore which preoperative clinical data and conventional magnetic resonance imaging (MRI) features may indicate the presence of hepatocellular carcinoma (HCC) in HCC patients coexisting with LR-3 and LR-4 lesions.

METHODS

HCC Patients coexisting with LR-3 and LR-4 lesions who participated in a prospective clinical trial (XX) were included in this study. Two radiologists independently assessed the preoperative MRI features and each lesion was assigned according to the liver imaging reporting and data system (LI-RADS). The preoperative clinical data were also evaluated. The relative values of these parameters were assessed as potential predictors of HCC for coexisting LR-3 and LR-4 lesions.

RESULTS

We enrolled 102 HCC patients (58.1 ± 11.5 years; 84.3% males) coexisting with 110 LR-3 and LR-4 lesions (HCCs group [n = 66]; non-HCCs group [n = 44]). The presence of restricted diffusion (OR: 18.590, p < 0.001), delayed enhancement (OR: 0.113, p < 0.001), and mild-moderate T2 hyperintensity (OR: 3.084, p = 0.048) were found to be independent predictors of HCC diagnosis. The sensitivity and specificity of the above independent variables for the diagnosis of HCC ranged from 66.7 to 80.3% and 56.8 to 88.6%, respectively. ROC analysis showed that, in discriminating HCC, the AUCs of the above factors were 0.777, 0.686, and 0.670, respectively. Combining these three findings for the prediction of HCC resulted in a specificity greater than 97%, and the AUC further increased to 0.874.

CONCLUSION

The presence of restricted diffusion, delayed enhancement, and mild-moderate T2 hyperintensity can be useful features for risk stratification of coexisting LR-3 and LR-4 lesions in HCC patients. Trial registration a prospective clinical trial (ChiCTR2000036201).

Best Practice for MRI Diagnostic Accuracy Research With Lessons and Examples from the LI-RADS Individual Participant Data Group

Medical imaging diagnostic test accuracy research is strengthened by adhering to best practices for study design, data collection, data documentation, and study reporting. In this review, key elements of such research are discussed, and specific recommendations provided for optimizing diagnostic accuracy study execution to improve uniformity, minimize common sources of bias and avoid potential pitfalls. Examples are provided regarding study methodology and data collection practices based on insights gained by the liver imaging reporting and data system (LI-RADS) individual participant data group, who have evaluated raw data from numerous MRI diagnostic accuracy studies for risk of bias and data integrity. The goal of this review is to outline strategies for investigators to improve research practices, and to help reviewers and readers better contextualize a study's findings while understanding its limitations. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3.

Hepatic Steatosis Has No Effect in Diagnosis Accuracy of LI-RADS v2018 Categorization of Hepatocellular Carcinoma in MR Imaging

BACKGROUND

In clinical practice, hepatocellular carcinoma (HCC) is widely diagnosed by using MRI, however, whether the imaging features are affected by hepatic steatosis (HS) is still unknown.

PURPOSE

To investigate and compare the differences in HCC related imaging features between with- and without-HS groups, and to further determine whether HS affects the diagnosis accuracy of Liver Imaging Reporting and Data System (LI-RADS) v2018 of HCC in MRI.

STUDY TYPE

Prospective.

SUBJECTS

One hundred and seventy-one patients (mean age, 52 ± 11 years; range, 26-83 years) including 137 men and 34 women.

FIELD STRENGTH/SEQUENCE

3.0 T, gradient echo (GRE).

ASSESSMENT

Subjects were classified as HS and non-HS groups according to MRI-proton density fat-fraction (PDFF). HS was defined as MRI-PDFF >5.6%. Three radiologists accessed HCC features and assigned LI-RADS categories in MRI independently based on LI-RADS v2018. Frequencies of HCC major features and LR categorization assignment between the two groups as well as interobserver agreement between the two radiologists were assessed.

STATISTICAL TESTS

Unpaired t-test, Chi-square test, Fisher's exact test, kappa statistic, intraclass correlation coefficient (ICC). A two-sided P value <0.05 was considered as statistically significant.

RESULTS

Major features including arterial hyperenhancement (APHE), enhancing "capsule" and nonperipheral "washout" observed between HS and non-HS groups were not significantly different (78.95% vs.78.62%, P = 0.866; 57.89% vs.52.98%, P = 0.483; and 75% vs.81.46%, P = 0.257, respectively), and the assessment of observation size showed a borderline difference (P = 0.059). No significant difference in LR-5 assignment between the two groups (69.74% vs. 72.85% for reader 1, P = 0.641; 71.05% vs. 72.19% for reader 2, P = 0.877). Interobserver agreement between the two radiologists showed almost perfect in LR-5 assignment (κ = 0.869) and size observation (ICC = 0.997).

DATA CONCLUSION

The diagnosis of HCC based on LI-RADS v2018 in MRI is of comparable performance regardless of HS, in which there is no significant difference in either the major imaging features or LR categorization.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 2.

The Value of LI-RADS and Radiomic Features from MRI for Predicting Microvascular Invasion in Hepatocellular Carcinoma within 5 cm

RATIONALE AND OBJECTIVES

To explore and compare the performance of LI-RADS® and radiomics from multiparametric MRI in predicting microvascular invasion (MVI) preoperatively in patients with solitary hepatocellular carcinoma (HCC)< 5 cm.

METHODS

We enrolled 143 patients with pathologically proven HCC and randomly stratified them into training (n = 100) and internal validation (n = 43) cohorts. Besides, 53 patients were enrolled to constitute an independent test cohort. Clinical factors and imaging features, including LI-RADS and three other features (non-smooth margin, incomplete capsule, and two-trait predictor of venous invasion), were reviewed and analyzed. Radiomic features from four MRI sequences were extracted. The independent clinic-imaging (clinical) and radiomics model for MVI-prediction were constructed by logistic regression and AdaBoost respectively. And the clinic-radiomics combined model was further constructed by logistic regression. We assessed the model discrimination, calibration, and clinical usefulness by using the area under the receiver operating characteristic curve (AUC), calibration curve, and decision-curve analysis respectively.

RESULTS

Incomplete tumor capsule, corona enhancement, and radiomic features were related to MVI in solitary HCC＜5 cm. The clinical model achieved AUC of 0.694/0.661 (training/internal validation). The single-sequence-based radiomic model's AUCs were 0.753-0.843/0.698-0.767 (training/internal validation). The combination model exhibited superior diagnostic performance to the clinical model (AUC: 0.895/0.848 [training/ internal validation]) and yielded an AUC of 0.858 in an independent test cohort.

CONCLUSION

Incomplete tumor capsule and corona enhancement on preoperative MRI were significantly related to MVI in solitary HCC＜5 cm. Multiple-sequence radiomic features potentially improve MVI-prediction-model performance, which could potentially help determining HCC's appropriate therapy.

Performance of LI-RADS category 5 vs combined categories 4 and 5: a systemic review and meta-analysis

OBJECTIVE

Computed tomography (CT)/magnetic resonance imaging (MRI) Liver Imaging Reporting and Data System (LI-RADS, LR) category 5 has high specificity and modest sensitivity for diagnosis of hepatocellular carcinoma (HCC). The purpose of this study was to compare the diagnostic performance of LR-5 vs combined LR-4 and LR-5 (LR-4/5) for HCC diagnosis.

METHODS

MEDLINE and EMBASE databases through January 03, 2023 were searched for studies reporting the performance of LR-5 and combined LR-4/5 for HCC diagnosis, using CT/MRI LI-RADS version 2014, 2017, or 2018. A bivariate random-effects model was used to calculate the pooled per-observation diagnostic performance. Subgroup analysis was performed based on imaging modalities and type of MRI contrast material.

RESULTS

Sixty-nine studies (15,108 observations, 9928 (65.7%) HCCs) were included. Compared to LR-5, combined LR-4/5 showed significantly higher pooled sensitivity (83.0% (95% CI [80.3-85.8%]) vs 65.7% (95% CI [62.4-69.1%]); p < 0.001), lower pooled specificity (75.0% (95% CI [70.5-79.6%]) vs 91.7% (95% CI [90.2-93.1%]); p < 0.001), lower pooled positive likelihood ratio (3.60 (95% CI [3.06-4.23]) vs 6.18 (95% CI [5.35-7.14]); p < 0.001), and lower pooled negative likelihood ratio (0.22 (95% CI [0.19-0.25]) vs 0.38 (95% CI [0.35-0.41]) vs; p < 0.001). Similar results were seen in all subgroups.

CONCLUSIONS

Our meta-analysis showed that combining LR-4 and LR-5 would increase sensitivity but decrease specificity, positive likelihood ratio, and negative likelihood ratio. These findings may inform management guidelines and individualized management.

CLINICAL RELEVANCE STATEMENT

This meta-analysis estimated the magnitude of changes in the sensitivity and specificity of imaging criteria when LI-RADS categories 4 and 5 were combined; these findings can inform management guidelines and individualized management.

KEY POINTS

There is no single worldwide reporting system for liver imaging, partly due to regional needs. Combining LI-RADS categories 4 and 5 increased sensitivity and decreased specificity and positive and negative likelihood ratios. Changes in the sensitivity and specificity of imaging criteria can inform management guidelines and individualized management.

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.

Optimizing LI-RADS: ancillary features screened from LR-3/4 categories can improve the diagnosis of HCC on MRI

OBJECTIVE

To determine the high-efficiency ancillary features (AFs) screened from LR-3/4 lesions and the HCC/non-HCC group and the diagnostic performance of LR3/4 observations.

MATERIALS AND METHODS

We retrospectively analyzed a total of 460 patients (with 473 nodules) classified into LR-3-LR-5 categories, including 311 cases of hepatocellular carcinoma (HCC), 6 cases of non-HCC malignant tumors, and 156 cases of benign lesions. Two faculty abdominal radiologists with experience in hepatic imaging reviewed and recorded the major features (MFs) and AFs of the Liver Imaging Reporting and Data System (LI-RADS). The frequency of the features and diagnostic performance were calculated with a logistic regression model. After applying the above AFs to LR-3/LR-4 observations, the sensitivity and specificity for HCC were compared.

RESULTS

The average age of all patients was 54.24 ± 11.32 years, and the biochemical indicators ALT (P = 0.044), TBIL (P = 0.000), PLT (P = 0.004), AFP (P = 0.000) and Child‒Pugh class were significantly higher in the HCC group. MFs, mild-moderate T2 hyperintensity, restricted diffusion and AFs favoring HCC in addition to nodule-in-nodule appearance were common in the HCC group and LR-5 category. AFs screened from the HCC/non-HCC group (AF-HCC) were mild-moderate T2 hyperintensity, restricted diffusion, TP hypointensity, marked T2 hyperintensity and HBP isointensity (P = 0.005, < 0.001, = 0. 032, p < 0.001, = 0.013), and the AFs screened from LR-3/4 lesions (AF-LR) were restricted diffusion, mosaic architecture, fat in mass, marked T2 hyperintensity and HBP isointensity (P < 0.001, = 0.020, = 0.036, < 0.001, = 0.016), which were not exactly the same. After applying AF-HCC and AF-LR to LR-3 and LR-4 observations in HCC group and Non-HCC group, After the above grades changed, the diagnostic sensitivity for HCC were 84.96% using AF-HCC and 85.71% using AF-LR, the specificity were 89.26% using AF-HCC and 90.60% using AF-LR, which made a significant difference (P = 0.000). And the kappa value for the two methods of AF-HCC and AF-LR were 0.695, reaching a substantial agreement.

CONCLUSION

When adjusting for LR-3/LR-4 lesions, the screened AFs with high diagnostic ability can be used to optimize LI-RADS v2018; among them, AF-LR is recommended for better diagnostic capabilities.

LI-RADS CT and MRI Ancillary Feature Association with Hepatocellular Carcinoma and Malignancy: An Individual Participant Data Meta-Analysis

Background The independent contribution of each Liver Imaging Reporting and Data System (LI-RADS) CT or MRI ancillary feature (AF) has not been established. Purpose To evaluate the association of LI-RADS AFs with hepatocellular carcinoma (HCC) and malignancy while adjusting for LI-RADS major features through an individual participant data (IPD) meta-analysis. Materials and Methods Medline, Embase, Cochrane Central Register of Controlled Trials, and Scopus were searched from January 2014 to January 2022 for studies evaluating the diagnostic accuracy of CT and MRI for HCC using LI-RADS version 2014, 2017, or 2018. Using a one-step approach, IPD across studies were pooled. Adjusted odds ratios (ORs) and 95% CIs were derived from multivariable logistic regression models of each AF combined with major features except threshold growth (excluded because of infrequent reporting). Liver observation clustering was addressed at the study and participant levels through random intercepts. Risk of bias was assessed using a composite reference standard and Quality Assessment of Diagnostic Accuracy Studies 2. Results Twenty studies comprising 3091 observations (2456 adult participants; mean age, 59 years ± 11 [SD]; 1849 [75.3%] men) were included. In total, 89% (eight of nine) of AFs favoring malignancy were associated with malignancy and/or HCC, 80% (four of five) of AFs favoring HCC were associated with HCC, and 57% (four of seven) of AFs favoring benignity were negatively associated with HCC and/or malignancy. Nonenhancing capsule (OR = 3.50 [95% CI: 1.53, 8.01]) had the strongest association with HCC. Diffusion restriction (OR = 14.45 [95% CI: 9.82, 21.27]) and mild-moderate T2 hyperintensity (OR = 10.18 [95% CI: 7.17, 14.44]) had the strongest association with malignancy. The strongest negative associations with HCC were parallels blood pool enhancement (OR = 0.07 [95% CI: 0.01, 0.49]) and marked T2 hyperintensity (OR = 0.18 [95% CI: 0.07, 0.45]). Seventeen studies (85%) had a high risk of bias. Conclusion Most LI-RADS AFs were independently associated with HCC, malignancy, or benignity as intended when adjusting for major features. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Crivellaro in this issue.

Association of LI-RADS and Histopathologic Features with Survival in Patients with Solitary Resected Hepatocellular Carcinoma

Background Both Liver Imaging Reporting and Data System (LI-RADS) and histopathologic features provide prognostic information in patients with hepatocellular carcinoma (HCC), but whether LI-RADS is independently associated with survival is uncertain. Purpose To assess the association of LI-RADS categories and features with survival outcomes in patients with solitary resected HCC. Materials and Methods This retrospective study included patients with solitary resected HCC from three institutions examined with preoperative contrast-enhanced CT and/or MRI between January 2008 and December 2019. Three independent readers evaluated the LI-RADS version 2018 categories and features. Histopathologic features including World Health Organization tumor grade, microvascular and macrovascular invasion, satellite nodules, and tumor capsule were recorded. Overall survival and disease-free survival were assessed with Cox regression models. Marginal effects of nontargetoid features on survival were estimated using propensity score matching. Results A total of 360 patients (median age, 64 years [IQR, 56-70 years]; 280 male patients) were included. At CT and MRI, the LI-RADS LR-M category was associated with increased risk of recurrence (CT: hazard ratio [HR] = 1.83 [95% CI: 1.26, 2.66], P = .001; MRI: HR = 2.22 [95% CI: 1.56, 3.16], P < .001) and death (CT: HR = 2.47 [95% CI: 1.72, 3.55], P < .001; MRI: HR = 1.80 [95% CI: 1.32, 2.46], P < .001) independently of histopathologic features. The presence of at least one nontargetoid feature was associated with an increased risk of recurrence (CT: HR = 1.80 [95% CI: 1.36, 2.38], P < .001; MRI: HR = 1.93 [95% CI: 1.81, 2.06], P < .001) and death (CT: HR = 1.51 [95% CI: 1.10, 2.07], P < .010) independently of histopathologic features. In matched samples, recurrence was associated with the presence of at least one nontargetoid feature at CT (HR = 2.06 [95% CI: 1.15, 3.66]; P = .02) or MRI (HR = 1.79 [95% CI: 1.01, 3.20]; P = .048). Conclusion In patients with solitary resected HCC, LR-M category and nontargetoid features were negatively associated with survival independently of histopathologic characteristics. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Kartalis and Grigoriadis in this issue.

Radiological diagnosis of hepatocellular carcinoma does not preclude biopsy before treatment

Background & Aims

The diagnosis of hepatocellular carcinoma (HCC) in patients with cirrhosis relies on non-invasive criteria based on international guidelines. The advent of systemic therapies warrants reconsideration of the role of biopsy specimens in the diagnosis of HCC. Accordingly, we investigated the diagnostic performance of the LI-RADS 2018 and the AASLD 2011 criteria.

Methods

Consecutive patients with cirrhosis who underwent a biopsy for suspected HCC between 2015 and 2020 were included. The available imaging studies (computed tomography and/or magnetic resonance imaging) were blindly reviewed by two independent radiologists. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were assessed for LI-RADS, AASLD, and biopsies.

Results

In total, 167 patients underwent both available biopsy and imaging. Of the 137 relevant biopsies, 114 patients had HCC (83.2%), 12 (9%) had non-HCC malignant lesions, and 11 (8%) had benign nodules. The PPV and NPV of the biopsies were 100% and 62%, respectively; 30 biopsies were non-contributive. The PPV and NPV of the LI-RADS categories were 89% and 32.8% for LR-5 and 85.5% and 54.5% for LR-4 + 5 + TIV, respectively. The PPV and NPV of the 2011 AASLD criteria were 93.2% and 35.6%, respectively. The interobserver kappa (k = 0.380) for the LR-5 categories was reasonable. Of 100 LR-5 nodules, 11 were misclassified, in particular one case was a colorectal metastasis, and two cases were cholangiocarcinomas, of which nine were identified through biopsy, whereas six were correctly classified according to LI-RADS (LR-M or LR-TIV). Fifty percent of macrotrabecular HCC and 48.4% of poorly differentiated HCC (Edmonson 3 and 4) were not classified as LR-5.

Conclusions

LI-RADS 2018 did not outperform the AASLD 2011 score as a non-invasive diagnosis of HCC. Tumor biopsy allowed restoration of an accurate diagnosis in 11% of LR-5 cases. A combined radiological and histological diagnosis should be considered mandatory for good treatment assessment.

Impact and Implications

Although biopsy is not required for hepatocellular carcinoma diagnosis when the LI-RADS criteria are met according to current guidelines, our study underscores the limits of radiology and the need for biopsy when hepatocellular carcinoma is suspected. Histological findings could change therapeutics of liver tumors even if only for a small proportion of patients. Histological proof of the type of cancer is a standard in oncology.

Threshold growth has a limited role in differentiating hepatocellular carcinoma from other focal hepatic lesions

BACKGROUND AND OBJECTIVE: The role of threshold growth, as one of the major features (MFs) of hepatocellular carcinoma (HCC) in the Liver Imaging Reporting and Data System (LI-RADS) is inconsistent. This study evaluated the LI-RADS diagnostic performance for HCC when threshold growth was removed or replaced by independently significant ancillary features (AFs). MATERIALS AND METHODS: This retrospective institutional review board-approved study included patients with a high HCC risk who underwent gadoxetic acid-enhanced MRIs. The MRI findings were consistent with pathologically proven focal hepatic observations. The pathological results were used as the gold standard reference. The sizes of the lesions with and without threshold growth were compared. Univariate and multivariate logistic regression analyses were used to confirm the independently significant AFs of HCC. In addition to the classification criteria of LI-RADS version 2018 (LI-RADS v2018), the lesions were also reclassified according to the following two schemes: scheme A, using all MFs except threshold growth, with threshold growth feature treated as an AF favouring malignancy; and scheme B, replacing the threshold growth feature with independently significant AFs and treated them as new MFs. The diagnostic performance of the above two LI-RADS schemes for HCC was calculated and compared with that of LI-RADS v2018. RESULTS: A total of 379 patients and 426 observations were included. Threshold growth was not an independent significant MF for HCC diagnosis [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.6-1.8; p = 0.927]. For all three groups of observations (HCCs, non-HCC malignancies, and benign lesions), the mean size with threshold growth was smaller than that without threshold growth (all p < 0.05). The nodule-in-nodule feature was an independent significant AF (OR, 9.8; 95% CI, 1.2-79.3; p = 0.032) and was used to replace threshold growth as a new MF in scheme B. The sensitivities of schemes A and B were 74.0% and 75.6%, respectively. The specificities of schemes A and B were the same (88.6%). None of the diagnostic performance metrics for HCC (sensitivity, specificity, accuracy) of either scheme A or B was significantly different from those of LI-RADS v2018 (all p > 0.05). CONCLUSION: Threshold growth is not an independently significant MF for HCC diagnosis. The diagnostic performance of LI-RADS for HCC is not affected regardless of whether threshold growth is removed from the list of MFs or replaced with an independently significant and more HCC-specific AF, which is the nodule-in-nodule feature.

Subcentimeter hepatocellular carcinoma (HCC) on gadoxetic-acid-enhanced MRI: less frequent typical imaging features compared to 1-2 cm HCC but better prognosis after surgical resection

PURPOSE

To compare the imaging features, pathologic characteristics, and survival outcomes between subcentimeter and 1-2 cm hepatocellular carcinoma (HCC).

METHODS

This retrospective observational study evaluated the imaging features and medical records of patients with HCC smaller than 2 cm who underwent surgical resection with preoperative gadoxetic-acid-enhanced MRI (EOB-MRI) from January 2013 to December 2021. The incidence of EOB-MRI features and pathological characteristics between the subcentimeter and 1-2 cm HCC were compared. The recurrence-free survival (RFS), including early and overall tumor recurrence, and overall survival (OS) were assessed.

RESULTS

A total of 223 patients (82 with subcentimeter HCC and 141 with 1-2 cm HCC, 179 men) were enrolled. Compared with 1-2 cm HCC, subcentimeter HCC showed fewer restricted diffusion (87.8 vs. 95.7%, P = 0.027), portal-phase washout (58.5% vs. 73.8%, P = 0.013), typical enhancement pattern (50.0% vs. 66.7%, P =0.014), and microvascular invasion (4.9% vs. 14.9%, P = 0.022). Patients with subcentimeter HCC had higher RFS (P = 0.027) and better OS (P = 0.029). The estimated RFS rates at 5 years was 83.3% for subcentimeter HCC and 67.3% for 1-2 cm HCC, respectively. The estimated OS rates at 5 years was 97.3% for subcentimeter HCC and 89.5% for 1-2 cm HCC, respectively.

CONCLUSION

Subcentimeter HCC showed less frequent EOB-MRI features seen typically in 1-2 cm HCC but better survival outcomes. Therefore, tailored early diagnostic criteria and immediate treatment for subcentimeter HCC may be warranted.

The role of enhancing capsule and modified capsule appearances in LI-RADS for diagnosing HCC ≤ 3.0 cm on gadoxetate disodium-enhanced MRI

OBJECTIVES

To evaluate the value of using enhancing capsule (EC) or modified capsule appearance as a major feature in LI-RADS for diagnosing HCC ≤ 3.0 cm on gadoxetate disodium-enhanced MRI (Gd-EOB-MRI), and to explore the relationship between the imaging features and the histological fibrous capsule.

METHODS

This retrospective study enrolled 342 hepatic lesions ≤ 3.0 cm in 319 patients that underwent Gd-EOB-MRIs from January 2018 to March 2021. During dynamic phases and hepatobiliary phase, the modified capsule appearance added the nonenhancing capsule (NEC) (modified LI-RADS + NEC) or corona enhancement (CoE) (modified LI-RADS + CoE) to EC as an alternative capsule appearance. Inter-reader agreement of imaging features was assessed. The diagnostic performances of LI-RADS, LI-RADS with EC ignored, and two modified LI-RADS were compared, followed by Bonferroni correction. Multivariable regression analysis was performed to identify the independent features associated with the histological fibrous capsule.

RESULTS

The inter-reader agreement on EC (0.64) was lower than that on the NEC alternative (0.71) but better than that on CoE alternative (0.58). For HCC diagnosis, compared to LI-RADS, LI-RADS with EC ignored showed significantly lower sensitivity (72.7% vs. 67.4%, p < 0.001) with comparable specificity (89.3% vs. 90.7%, p = 1.000). Two modified LI-RADS showed slightly higher sensitivity and lower specificity than LI-RADS, without statistical significance (all p ≥ 0.006). The AUC was highest with modified LI-RADS + NEC (0.82). Both EC and NEC were significantly associated with the fibrous capsule (p < 0.05).

CONCLUSION

EC appearance improved the diagnostic sensitivity of LI-RADS for HCC ≤ 3.0 cm on Gd-EOB-MRI. Considering NEC as an alternative capsule appearance allowed for better inter-reader reliability and comparable diagnostic ability.

KEY POINTS

• Using the enhancing capsule as a major feature in LI-RADS significantly improved the sensitivity of diagnosing HCC ≤ 3.0 cm without reducing specificity on gadoxetate disodium-enhanced MRI. • Compared to the corona enhancement, the nonenhancing capsule might be a preferable alternative capsule appearance for diagnosing HCC ≤ 3.0 cm. • Capsule appearance should be considered a major feature in LI-RADS for diagnosing HCC ≤ 3.0 cm, regardless whether the capsule appears to be enhancing or nonenhancing.

Diagnostic Value of CT Delayed Phase Images Added to Gd-EOB-DTPA MRI for HCC Diagnosis in LR-3/4 Lesions

Objective

To explore the potential value of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) magnetic resonance imaging (MRI) in the diagnosis of hepatocellular carcinoma (HCC) in LR-3/4 lesions by adding computed tomography (CT) delayed images based on the Liver Imaging Reporting And Data System (LI-RADS).

Methods

The differences in clinical and imaging characteristics between hepatocellular carcinoma and non-HCC were compared, and logistic regression was used to analyze the imaging risk factors for the diagnosis of HCC. Based on the main and HCC-specific auxiliary features of Gd-EOB-DTPA MRI, the HCC diagnostic model 1 was established, and the diagnostic efficacy was analyzed. Based on model 1, delayed phase CT images were added to establish model 2 to find reliable predictors of HCC diagnosis. Receiver operating characteristic (ROC) analysis and the DeLong test were used to compare the two models.

Results

There was a significant difference in serum AFP between HCC and non-HCC (P = 0.008). Based on main and HCC-specific auxiliary features of Gd-EOB-DTPA MRI, enhancing capsule (OR = 0.197, 95% CI = 0.06-0.595, P = 0.005) and washout (OR = 10.345, 95% CI = 3.460-30.930, P < 0.001) were independent risk factors in Model 1. After adding CT delayed-phase images to build model 2, enhancing capsule (OR = 0.132, 95% CI = 0.139-0.449, P = 0.001), MRI and (or) CT washout (OR = 0.052, 95% CI = 0.016-0.172, P < 0.001) were reliable predictors for HCC diagnosis. The AUC of model 1 was 0.808, sensitivity was 63.46%, and specificity was 85.00%. The AUC of model 2 was 0.854, the sensitivity was 71.20%, and the specificity was 85.00%. DeLong test (P = 0.040) demonstrated the diagnostic efficacy of model 2 significantly superior than model 1.

Conclusion

Tumor washout and enhanced capsule are reliable factors for the diagnosis of HCC. Gd-EOB-DTPA MRI with delayed phase CT images can improve the sensitivity and diagnostic efficiency of HCC in LR-3/4 lesions on the premise of maintaining high specificity. Future studies are required to reinforce our finding.

A Multicenter Assessment of Interreader Reliability of LI-RADS Version 2018 for MRI and CT

Background Various limitations have impacted research evaluating reader agreement for Liver Imaging Reporting and Data System (LI-RADS). Purpose To assess reader agreement of LI-RADS in an international multicenter multireader setting using scrollable images. Materials and Methods This retrospective study used deidentified clinical multiphase CT and MRI and reports with at least one untreated observation from six institutions and three countries; only qualifying examinations were submitted. Examination dates were October 2017 to August 2018 at the coordinating center. One untreated observation per examination was randomly selected using observation identifiers, and its clinically assigned features were extracted from the report. The corresponding LI-RADS version 2018 category was computed as a rescored clinical read. Each examination was randomly assigned to two of 43 research readers who independently scored the observation. Agreement for an ordinal modified four-category LI-RADS scale (LR-1, definitely benign; LR-2, probably benign; LR-3, intermediate probability of malignancy; LR-4, probably hepatocellular carcinoma [HCC]; LR-5, definitely HCC; LR-M, probably malignant but not HCC specific; and LR-TIV, tumor in vein) was computed using intraclass correlation coefficients (ICCs). Agreement was also computed for dichotomized malignancy (LR-4, LR-5, LR-M, and LR-TIV), LR-5, and LR-M. Agreement was compared between research-versus-research reads and research-versus-clinical reads. Results The study population consisted of 484 patients (mean age, 62 years ± 10 [SD]; 156 women; 93 CT examinations, 391 MRI examinations). ICCs for ordinal LI-RADS, dichotomized malignancy, LR-5, and LR-M were 0.68 (95% CI: 0.61, 0.73), 0.63 (95% CI: 0.55, 0.70), 0.58 (95% CI: 0.50, 0.66), and 0.46 (95% CI: 0.31, 0.61) respectively. Research-versus-research reader agreement was higher than research-versus-clinical agreement for modified four-category LI-RADS (ICC, 0.68 vs 0.62, respectively; P = .03) and for dichotomized malignancy (ICC, 0.63 vs 0.53, respectively; P = .005), but not for LR-5 (P = .14) or LR-M (P = .94). Conclusion There was moderate agreement for LI-RADS version 2018 overall. For some comparisons, research-versus-research reader agreement was higher than research-versus-clinical reader agreement, indicating differences between the clinical and research environments that warrant further study. © RSNA, 2023 Supplemental material is available for this article. See also the editorials by Johnson and Galgano and Smith in this issue.

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.

LI-RADS v2018: utilizing ancillary features on gadoxetic acid-enhanced MRI to improve the diagnostic performance of small hapatocellular carcinoma (≤ 20 mm)

PURPOSE

To evaluate the role of ancillary features (AFs) of Liver Imaging Reporting and Data System (LI-RADS) in the diagnostic performance of small HCC (≤ 20 mm) on gadoxetic acid-enhanced MRI.

METHODS

A total of 154 patients with 183 hepatic observations were analysed in this retrospective study. Observations were categorized using only major features (MFs) and combined MFs and AFs. Independently significant AFs were identified through logistic regression analysis, and upgraded LR-5 criteria were developed using these as new MFs. The diagnostic performance of the modified LI-RADS (mLI-RADS) was calculated and compared with that of LI-RADS v2018 using McNemar's test.

RESULTS

Restricted diffusion, transitional and hepatobiliary phase hypointensity were independently significant AFs. The mLI-RADS a, c, e, g, h and i (upgraded LR-4 lesions that were categorized using only MFs to LR-5 using a certain or any one, two, three of the above AFs as new MFs) yielded a significantly greater sensitivity than that of the LI-RADS v2018 (68.0%, 69.1%, 69.1%, 69.1%, 69.1%, 68.0% vs. 61.9%, all p < 0.05), whereas the specificities were not significantly different (84.9%, 86.0%, 84.9%, 83.7%, 84.9%, 87.2% vs. 88.4% all p > 0.05). When independently significant AFs were used to upgrade the LR-4 nodules categorized by combined MFs and AFs (mLI-RADS b, d and f), the sensitivities were improved, but the specificities were decreased (all p < 0.05).

CONCLUSIONS

Independently significant AFs may be used to upgrade an observation from LR-4 (categorized only using MFs) to LR-5, which can improve diagnostic performance for small HCC.

Can MRI features predict clinically relevant hepatocellular carcinoma genetic subtypes?

PURPOSE

Recent studies in cancer genomics have revealed core drivers for hepatocellular carcinoma (HCC) pathogenesis. We aim to study whether MRI features can serve as non-invasive markers for the prediction of common genetic subtypes of HCC.

METHODS

Sequencing of 447 cancer-implicated genes was performed on 43 pathology proven HCC from 42 patients, who underwent contrast-enhanced MRI followed by biopsy or resection. MRI features were retrospectively evaluated including tumor size, infiltrative tumor margin, diffusion restriction, arterial phase hyperenhancement, non-peripheral washout, enhancing capsule, peritumoral enhancement, tumor in vein, fat in mass, blood products in mass, cirrhosis and tumor heterogeneity. Fisher's exact test was used to correlate genetic subtypes with imaging features. Prediction performance using correlated MRI features for genetic subtype and inter-reader agreement were assessed.

RESULTS

The two most prevalent genetic mutations were TP53 (13/43, 30%) and CTNNB1 (17/43, 40%). Tumors with TP53 mutation more often demonstrated an infiltrative tumor margin on MRI (p = 0.01); inter-reader agreement was almost perfect (kappa = 0.95). The CTNNB1 mutation was associated with peritumoral enhancement on MRI (p = 0.04), inter-reader agreement was substantial (kappa = 0.74). The MRI feature of an infiltrative tumor margin correlated with the TP53 mutation with accuracy, sensitivity, and specificity of 74.4%, 61.5% and 80.0%, respectively. Peritumoral enhancement correlated with the CTNNB1 mutation with accuracy, sensitivity, and specificity of 69.8%, 47.0% and 84.6%, respectively.

CONCLUSION

An infiltrative tumor margin on MRI correlated with TP53 mutation and peritumoral enhancement correlated with CTNNB1 mutation in HCC. Absence of these MRI features are potential negative predictors of the respective HCC genetic subtypes that have implications for prognosis and treatment response.

Ring-like enhancement on Contrast-Enhanced ultrasound may correlate well with histopathological capsule of Hepatocellular Carcinoma: Comparison with the enhancing capsule on Gadopentetate-enhanced MRI

PURPOSE

To evaluate the correlation of ring-like enhancement (RE) on contrast-enhanced ultrasound with Sonazoid (S-CEUS) with the fibrous capsule of HCC, and compared it with the enhancing capsule on Gadopentetate-enhanced MRI (Gd-MRI).

METHOD

Consecutive patients with pathologically-proven resected HCCs from January 2021 to December 2021 were reviewed in this retrospective study. Preoperatively, the RE on the S-CEUS and the enhancing capsule on Gd-MRI were evaluated for each lesion. We analyzed the correlation of the presence, integrity, and thickness of imaging features with the histopathological fibrous capsule. The diagnostic performance to recognize the capsule between two modalities was compared by the McNemar test.

RESULTS

Ninety-one patients (mean age, 58.30 ± 11.13 years; 82 men) with ninety-seven HCCs (mean size, 4.67 ± 2.70 cm) were reviewed. The RE on S-CEUS correlated with the presence of the fibrous capsule (P = 0.006). The sensitivity, specificity, and accuracy were 92.05 %, 44.44 %, and 82.47 %, respectively, which was not different from Gd-MRI (P = 0.388). The integrity of RE in the post-vascular phase correlated with the integrity of the fibrous capsule (P = 0.018), whose diagnostic performance was not statistically different from Gd-MRI (P > 0.999). The thickness shown both on S-CEUS and Gd-MRI was thicker than that in histopathology (P < 0.001), and the thickness on Gd-MRI was not statistically different from that in the vascular phase of S-CEUS (P = 0.563), but thinner than that in the post-vascular phase (P = 0.001).

CONCLUSIONS

Compared with the Gd-MRI, RE on S-CEUS had a similarly well correlation with the presence and integrity of fibrous capsule of HCC.

Value of threshold growth as a major diagnostic feature of hepatocellular carcinoma in LI-RADS

BACKGROUND & AIMS

The Liver Reporting and Data System (LI-RADS) version 2018 simplified the definition of threshold growth to '≥50% size increase in a mass in ≤6 months'. However, the diagnostic value of threshold growth for hepatocellular carcinoma (HCC) remained unclear. We evaluated the value of threshold growth, as defined by LI-RADS v2018, in diagnosing HCCs.

METHODS

Patients who underwent preoperative gadoxetate disodium-enhanced MRI because of the presence of LI-RADS category 2, 3, or 4 rather than category 5 on prior CT/MRI between January 2017 and December 2020 were retrospectively evaluated. Pathologic or clinical diagnoses were used as reference standards. Imaging features were evaluated by three readers according to LI-RADS v2018. The frequency and diagnostic odds ratio of threshold growth were calculated. The diagnostic performance of LI-RADS category 5 was separately evaluated when threshold growth was and was not considered a major feature, and results were compared using generalized estimation equations. Subgroups of patients who underwent CT/MRI during the previous 3-6 months were analyzed.

RESULTS

Analysis of 340 observations in 243 patients found that the frequency of threshold growth was 18.8% and it gradually increased over time. Threshold growth was significantly associated with HCC (diagnostic odds ratio 5.2; 95% CI 2.1-12.7; p <0.001). Use of threshold growth as a major feature significantly increased sensitivity in both the overall (66.4% vs. 57.3%, p <0.001) and subgroup (73.4% vs. 58.2%, p <0.001) cohorts, but had no effect on specificity in either the overall (97.5% vs. 98.3%, p = 0.319) or subgroup (95.9% vs. 98.0%, p = 0.323) cohorts.

CONCLUSION

The revised threshold growth of LI-RADS v2018 was significantly associated with HCC. Use of threshold growth as a major diagnostic feature of HCC can improve the sensitivity of LI-RADS v2018.

IMPACT AND IMPLICATIONS

We found that the revised threshold growth in the Liver Imaging Reporting and Data System version 2018 (LI-RADS v2018) was a significant predictor of hepatocellular carcinoma (HCC). The use of threshold growth as a major imaging feature of HCC significantly increased the sensitivity of LI-RADS v2018, especially small HCCs (≤3.0 cm), compared with its non-use. Because these small HCCs are eligible for curative treatments, the additional detection of small HCCs is clinically meaningful.

Utilization of a Machine Learning Algorithm for the Application of Ancillary Features to LI-RADS Categories LR3 and LR4 on Gadoxetate Disodium-Enhanced MRI

BACKGROUND

This study aimed to identify the important ancillary features (AFs) and determine the utilization of a machine-learning-based strategy for applying AFs for LI-RADS LR3/4 observations on gadoxetate disodium-enhanced MRI.

METHODS

We retrospectively analyzed MRI features of LR3/4 determined with only major features. Uni- and multivariate analyses and random forest analysis were performed to identify AFs associated with HCC. A decision tree algorithm of applying AFs for LR3/4 was compared with other alternative strategies using McNemar's test.

RESULTS

We evaluated 246 observations from 165 patients. In multivariate analysis, restricted diffusion and mild-moderate T2 hyperintensity showed independent associations with HCC (odds ratios: 12.4 [p < 0.001] and 2.5 [p = 0.02]). In random forest analysis, restricted diffusion is the most important feature for HCC. Our decision tree algorithm showed higher AUC, sensitivity, and accuracy (0.84, 92.0%, and 84.5%) than the criteria of usage of restricted diffusion (0.78, 64.5%, and 76.4%; all p < 0.05); however, our decision tree algorithm showed lower specificity than the criterion of usage of restricted diffusion (71.1% vs. 91.3%; p < 0.001).

CONCLUSION

Our decision tree algorithm of applying AFs for LR3/4 shows significantly increased AUC, sensitivity, and accuracy but reduced specificity. These appear to be more appropriate in certain circumstances in which there is an emphasis on the early detection of HCC.

Percentages of Hepatocellular Carcinoma in LI-RADS Categories with CT and MRI: A Systematic Review and Meta-Analysis

Background The Liver Imaging Reporting and Data System (LI-RADS) CT and MRI algorithm applies equally to CT, MRI with extracellular contrast agents (ECA-MRI), and MRI with gadoxetate (Gx-MRI). Purpose To estimate pooled percentages of hepatocellular carcinoma (HCC) and overall malignancy for each LI-RADS category with CT and MRI. Materials and Methods MEDLINE and EMBASE databases were searched for research articles (January 2014-April 2021) reporting the percentages of observations in each LI-RADS category with use of versions 2014, 2017, or 2018. Study design, population characteristics, imaging modality, reference standard, and numbers of HCC and non-HCC malignancies in each category were recorded. A random-effects model evaluated the pooled percentage of HCC and overall malignancy for each category. Results There were 49 studies with 9620 patients and a total 11 562 observations, comprising 7921 HCCs, 1132 non-HCC malignancies, and 2509 benign entities. No HCC or non-HCC malignancies were reported with any modality in the LR-1 category. The pooled percentages of HCC for CT, ECA-MRI, and Gx-MRI, respectively, were 10%, 6%, and 1% for LR-2 (P = .16); 48%, 31%, and 38% for LR-3 (P = .42); 76%, 64%, and 77% for LR-4 (P = .62); 96%, 95%, and 96% for LR-5 (P = .76); 88%, 76%, and 78% for LR-5V or LR-TIV (tumor in vein) (P = .42); and 20%, 30%, and 35% for LR-M (P = .32). Most LR-M (93%-100%) and LR-5V or LR-TIV (99%-100%) observations were malignant, regardless of modality. Conclusion There was no difference in percentages of hepatocellular carcinoma and overall malignancy between CT, MRI with extracellular contrast agents, and MRI with gadoxetate for any Liver Imaging Reporting and Data System categories. © RSNA, 2023 Supplemental material is available for this article See also the editorial by Ronot in this issue.

Efficacy of LR-5 and LR-4/5 by Liver Imaging Reporting and Data System (MRI) for hepatocellular carcinoma: A meta-analysis

To comprehensive investigate the diagnostic efficacy of LR-5 and LR-4/5 by MRI LI-RADS of suspected liver nodules. A comprehensive search of authenticated international databases including PubMed/Medline, Ovid, Embase, Web of Science as well as a series of nation-level databases, including China National Knowledge Infrastructure was carried out to look for related studies with respect to the diagnostic performance of MRI LR-5 or LR-4/5 for HCC. Subsequently, main data including the basic information of the articles incorporated as well as main outcomes, including diagnostic sensitivity, specificity, accuracy, or original data like true positive, false positive, true negative and false negative values were extracted. Next, forest plots were generated to reveal the pooled diagnostic sensitivity, specificity. The diagnostic sensitivity, specificity of LR-5 and LR-4/5 by LI-RADS were comparatively satisfactory. The pooled diagnostic sensitivity and specificity of MRI LR-5 with respect to pathologically diagnosed HCC were 0.73 [95% CI 0.7-0.75] and 0.88 [95% CI 0.86-0.90] respectively. The pooled sensitivity and specificity of MRI LR-4/5 were 0.77 [95% CI 0.75-0.80] and 0.82 [95% CI 0.79-0.85] respectively. Through this systematic review and meta-analysis, we found a promisingly satisfactory diagnostic efficacy of LR-5 and LR-4/5 by MRI LI-RADS of suspected malignant liver nodules, manifested by optimal diagnostic sensitivity, specificity, and accuracy.

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

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

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.

HCC or Something Else? Frequency of Various Benign and Malignant Etiologies in Cirrhotic Patients with Newly Detected Focal Liver Lesions in Relation to Different Clinical and Sonographic Parameters

Background and Aims: To investigate the frequency of different benign and malignant focal liver lesions (FLLs) in relation to clinical and sonographic features among patients with liver cirrhosis (LC) and newly detected FLLs. Methods: This study was a retrospective analysis of 225 cirrhotic patients with newly detected FLLs who underwent hepatic ultrasound (US) examinations at our university hospital from 2011 to 2022. The diagnosis of FLLs was based on histology and/or consensus radiological criteria, in accordance with the current diagnostic guidelines. The FLLs were classified into benign (bFLLs) or malignant (mFLLs) lesions and the latter group was subclassified into HCC and non-HCC mFLLs. The frequency, clinical parameters, and sonographic features of the different groups were examined and compared. Results: Of the 225 FLLs, 154 (68.4%) were mFLLs and 71 (31.6%) bFLLs. HCC was the most frequent subcategory of FLLs (132; 58.7%). There were (22; 9.8%) non-HCC mFLLs with 11 (4.9%) metastases and 11 (4.9%) non-HCC primary liver tumors. Regenerative nodules (RNs) were the most frequent form of bFLLs (25; 11.1%), followed by simple cysts (22; 9.8%) and hemangiomas (14; 6.2%). The other bFLLs (10; 14.1%) were fat deposition/sparing (5), hematomas (2), abscesses (2), and echinococcal cysts (1). The distribution of bFLLs and HCC and non-HCC mFLLs varied significantly according to the clinical scenarios. HCC mFLLs were more frequent in males (p = 0.001), in those with no history of active non-hepatic primary malignant disease (NHPMD) (p < 0.001), in those with a hepatitis B or C etiology of LC (p = 0.002), when located in the right lobe (p = 0.008), and when portal vein thrombosis was present (p = 0.03). Conclusion: In cirrhotic patients with newly detected FLLs, the non-HCC etiology was more frequently diagnosed in lesions that were located in the left lobe, in females, and in patients with a history of active NHPMD. Thus, the lower frequency of HCC in the abovementioned groups demonstrated that a cautious implementation of the current consensus radiological criteria would be required for these groups, particularly in patients with an active NHPMD, given the fact that the consensus criteria were not validated in these populations. A more active diagnostic approach may ultimately be needed for these patients. Large prospective studies are needed to validate these findings.

Modifying LI-RADS on Gadoxetate Disodium-Enhanced MRI: A Secondary Analysis of a Prospective Observational Study

BACKGROUND

The Liver Imaging Reporting and Data System (LI-RADS) is widely used for diagnosing hepatocellular carcinoma (HCC), however, with unsatisfactory sensitivity, complex ancillary features, and inadequate integration with gadoxetate disodium (EOB)-enhanced MRI.

PURPOSE

To modify LI-RADS (mLI-RADS) on EOB-MRI.

STUDY TYPE

Secondary analysis of a prospective observational study.

POPULATION

Between July 2015 and September 2018, 224 consecutive high-risk patients (median age, 51 years; range, 26-83; 180 men; training/testing sets: 169/55 patients) with 742 (median size, 13 mm; interquartile range, 7-27; 498 HCCs) LR-3/4/5 observations.

FIELD STRENGTH/SEQUENCE

3.0 T T₂ -weighted fast spin-echo, diffusion-weighted spin-echo based echo-planar, and 3D T₁ -weighted gradient echo sequences.

ASSESSMENT

Three radiologists (with 5, 5, and 10 years of experience in liver MR imaging, respectively) blinded to the reference standard (histopathology or imaging follow-up) reviewed all MR images independently. In the training set, the optimal LI-RADS version 2018 (v2018) features selected by Random Forest analysis were used to develop mLI-RADS via decision tree analysis.

STATISTICAL TESTS

In an independent testing set, diagnostic performances of mLI-RADS, LI-RADS v2018, and the Korean Liver Cancer Association (KLCA) guidelines were computed using a generalized estimating equation model and compared with McNemar's test. A two-tailed P < 0.05 was statistically significant.

RESULTS

Five features (nonperipheral "washout," restricted diffusion, nonrim arterial phase hyperenhancement [APHE], mild-moderate T2 hyperintensity, and transitional phase hypointensity) constituted mLI-RADS, and mLR-5 was nonperipheral washout coupled with either nonrim APHE or restricted diffusion. In the testing set, mLI-RADS was significantly more sensitive (72%) and accurate (80%) than LI-RADS v2018 (sensitivity, 61%; accuracy 74%; both P < 0.001) and the KLCA guidelines (sensitivity, 64%; accuracy 74%; both P < 0.001), without sacrificing positive predictive value (mLI-RADS, 94%; LI-RADS v2018, 94%; KLCA guidelines, 92%).

DATA CONCLUSION

In high-risk patients, the EOB-MRI-based mLI-RADS was simpler and more sensitive for HCC than LI-RADS v2018 while maintaining high positive predictive value.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

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

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

Fat-only Dixon: how to use it in body MRI

The Dixon method for fat/water separation is widely used to obtain uniform fat suppression using the water-only reconstruction. However, the fat-only reconstruction is potentially neglected in clinical practice, either not sent to the PACS or ignored upon imaging review. Fat-only Dixon provides a valuable tool for rapid screening for microscopic fat and problem-solving of lesions of interest. This work will review the physics of Dixon fat/water separation, some clinical applications, artifacts, and protocol design considerations of Dixon imaging, and how to integrate the Dixon method into the clinical practice of body MRI.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Computed Tomography Nomogram for Assessing the Malignancy Risk of Focal Liver Lesions in Patients With Cirrhosis: A Preliminary Study

Purpose

The detection and characterization of focal liver lesions (FLLs) in patients with cirrhosis is challenging. Accurate information about FLLs is key to their management, which can range from conservative methods to surgical excision. We sought to develop a nomogram that incorporates clinical risk factors, blood indicators, and enhanced computed tomography (CT) imaging findings to predict the nature of FLLs in cirrhotic livers.

Method

A total of 348 surgically confirmed FLLs were included. CT findings and clinical data were assessed. All factors with P < 0.05 in univariate analysis were included in multivariate analysis. ROC analysis was performed, and a nomogram was constructed based on the multivariate logistic regression analysis results.

Results

The FLLs were either benign (n = 79) or malignant (n = 269). Logistic regression evaluated independent factors that positively affected malignancy. AFP (OR = 10.547), arterial phase hyperenhancement (APHE) (OR = 740.876), washout (OR = 0.028), satellite lesions (OR = 15.164), ascites (OR = 156.241), and nodule-in-nodule architecture (OR =27.401) were independent predictors of malignancy. The combined predictors had excellent performance in differentiating benign and malignant lesions, with an AUC of 0.959, a sensitivity of 95.24%, and a specificity of 87.5% in the training cohort and AUC of 0.981, sensitivity of 94.74%, and specificity of 93.33% in the test cohort. The C-index was 96.80%, and calibration curves showed good agreement between the nomogram predictions and the actual data.

Conclusions

The nomogram showed excellent discrimination and calibration for malignancy risk prediction, and it may aid in making FLLs treatment decisions.

Data-Driven Modification of the LI-RADS Major Feature System on Gadoxetate Disodium-Enhanced MRI: Toward Better Sensitivity and Simplicity

BACKGROUND

The Liver Imaging Reporting and Data System (LI-RADS) is widely accepted as a reliable diagnostic scheme for hepatocellular carcinoma (HCC) in at-risk patients. However, its application is hampered by substantial complexity and suboptimal diagnostic sensitivity.

PURPOSE

To propose data-driven modifications to the LI-RADS version 2018 (v2018) major feature system (rLI-RADS) on gadoxetate disodium (EOB)-enhanced magnetic resonance imaging (MRI) to improve sensitivity and simplicity while maintaining high positive predictive value (PPV) for detecting HCC.

STUDY TYPE

Retrospective.

POPULATION

Two hundred and twenty-four consecutive at-risk patients (training dataset: 169, independent testing dataset: 55) with 742 LR-3 to LR-5 liver observations (HCC: N = 498 [67%]) were analyzed from a prospective observational registry collected between July 2015 and September 2018.

FIELD STRENGTH/SEQUENCE

3.0 T/T2-weighted fast spin-echo, diffusion-weighted spin-echo based echo-planar and three-dimensional (3D) T1-weighted gradient echo sequences.

ASSESSMENT

All images were evaluated by three independent abdominal radiologists who were blinded to all clinical, pathological, and follow-up information. Composite reference standards of either histopathology or imaging follow-up were used.

STATISTICAL TESTS

In the training dataset, LI-RADS v2018 major features were used to develop rLI-RADS based on their associated PPV for HCC. In an independent testing set, diagnostic performances of LI-RADS v2018 and rLI-RADS were computed using a generalized estimating equation model and compared with McNemar's test. A P value <0.05 was considered statistically significant.

RESULTS

The median (interquartile range) size of liver observations was 13 mm (7-27 mm). The diagnostic table for rLI-RADS encompassed 9 cells, as opposed to 16 cells for LI-RADS v2018. In the testing set, compared to LI-RADS v2018, rLI-RADS category 5 demonstrated a significantly superior sensitivity (76% vs. 61%) while maintaining comparably high PPV (92.5% vs. 94.1%, P = 0.126).

DATA CONCLUSION

Compared with LI-RADS v2018, rLI-RADS demonstrated improved simplicity and significantly superior diagnostic sensitivity for HCC in at-risk patients.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

CT/MRI and CEUS LI-RADS Major Features Association with Hepatocellular Carcinoma: Individual Patient Data Meta-Analysis

Background The Liver Imaging Reporting and Data System (LI-RADS) assigns a risk category for hepatocellular carcinoma (HCC) to imaging observations. Establishing the contributions of major features can inform the diagnostic algorithm. Purpose To perform a systematic review and individual patient data meta-analysis to establish the probability of HCC for each LI-RADS major feature using CT/MRI and contrast-enhanced US (CEUS) LI-RADS in patients at high risk for HCC. Materials and Methods Multiple databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Scopus) were searched for studies from January 2014 to September 2019 that evaluated the accuracy of CT, MRI, and CEUS for HCC detection using LI-RADS (CT/MRI LI-RADS, versions 2014, 2017, and 2018; CEUS LI-RADS, versions 2016 and 2017). Data were centralized. Clustering was addressed at the study and patient levels using mixed models. Adjusted odds ratios (ORs) with 95% CIs were determined for each major feature using multivariable stepwise logistic regression. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) (PROSPERO protocol: CRD42020164486). Results A total of 32 studies were included, with 1170 CT observations, 3341 MRI observations, and 853 CEUS observations. At multivariable analysis of CT/MRI LI-RADS, all major features were associated with HCC, except threshold growth (OR, 1.6; 95% CI: 0.7, 3.6; P = .07). Nonperipheral washout (OR, 13.2; 95% CI: 9.0, 19.2; P = .01) and nonrim arterial phase hyperenhancement (APHE) (OR, 10.3; 95% CI: 6.7, 15.6; P = .01) had stronger associations with HCC than enhancing capsule (OR, 2.4; 95% CI: 1.7, 3.5; P = .03). On CEUS images, APHE (OR, 7.3; 95% CI: 4.6, 11.5; P = .01), late and mild washout (OR, 4.1; 95% CI: 2.6, 6.6; P = .01), and size of at least 20 mm (OR, 1.6; 95% CI: 1.04, 2.5; P = .04) were associated with HCC. Twenty-five studies (78%) had high risk of bias due to reporting ambiguity or study design flaws. Conclusion Most Liver Imaging Reporting and Data System major features had different independent associations with hepatocellular carcinoma; for CT/MRI, arterial phase hyperenhancement and washout had the strongest associations, whereas threshold growth had no association. © RSNA, 2021 Online supplemental material is available for this article.

Tumor size-based validation of contrast-enhanced ultrasound liver imaging reporting and data system (CEUS LI-RADS) 2017 for hepatocellular carcinoma characterizing

OBJECTIVES

To validate the efficacy of contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS) and its major features in diagnosing hepatocellular carcinoma (HCC) of different sizes in high-risk patients.

METHODS

Between January 2014 and December 2015, a total of 545 untreated liver nodules were included. These liver nodules were divided into two groups (<20 mm and ≥20 mm). Each nodule was classified based on CEUS LI-RADS. The diagnostic performance comparison was assessed by the chi-square test, with pathology results as the golden criterion.

RESULTS

The accuracy, sensitivity, specificity, and positive predictive value (PPV) of CEUS LR-5 criteria in <20 mm group vs ≥20 mm group in diagnosing HCC were 60.5% vs 59.8%, 55.6% vs 57.6%, 85.7% vs 88.6 and 95.2% vs 98.5%, respectively, without significant difference (all p > 0.05). The accuracy, sensitivity and PPV of LR5/M for malignancy in <20 mm group were lower than in ≥20 mm group, with values of 79.1% vs 95.0%, 84.2% vs 95.7 and 91.4% vs 99.2%, respectively (p < 0.05).

CONCLUSIONS

The CEUS LI-RADS has a comparable performance for diagnosing HCC between lesions ≥ 20 mm and <20 mm. For diagnosing malignancy including HCC, it has a higher efficacy for lesions ≥ 20 mm than <20 mm.

ADVANCES IN KNOWLEDGE

1.For diagnosing HCC, CEUS LI-RADS has comparable performances between lesions ≥ 20 mm and <20 mm.2. For diagnosing malignancy including HCC, CEUS LI-RADS has a higher efficacy for lesions ≥ 20 mm than <20 mm.

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

INTRODUCTION AND OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

LI-RADS ancillary features favoring benignity: is there a role in LR-5 observations?

OBJECTIVES

The Liver Imaging Reporting and Data System algorithm allows category downgrade in the presence of ancillary features (AFs) favoring benignity, even in observations categorized as LR-5. This study aims to assess the role of AFs favoring benignity in LR-5 observations and their impact on category downgrade.

METHODS

This study included high-risk patients with at least one LR-5 observation imaged with gadoxetate disodium MRI. Three readers with different experience levels independently evaluated the presence of AFs favoring malignancy (not hepatocellular carcinoma (HCC) in particular and HCC in particular) and AFs favoring benignity. Category downgrade was considered possible in the presence of ≥ 1 AF favoring benignity and no AF favoring malignancy. Correlation between observations size and number of AFs was assessed using Spearman's rank correlation coefficient. Cohen's kappa (k) test was used to assess inter-reader agreement.

RESULTS

The final study cohort included 162 LR-5 (mean size: 23 ± 16 mm) in 119 patients. AFs favoring benignity were reported in 9 (5.6%), 20 (12.3%), and 10 (6.2%) LR-5 observations by reader 1, reader 2, and reader 3, respectively. Hepatobiliary phase isointensity was observed in 6 (3.7%), 2 (1.2%), and 7 (4.3%) observations, respectively. Category downgrade was considered possible in only one (0.6%) observation by reader 1 and reader 3. There was a significant correlation between observation size and number of AFs favoring malignancy (p < 0.001), not HCC in particular (p ≤ 0.010), and favoring HCC in particular (p < 0.001). Inter-reader agreement of AFs favoring benignity was poor to moderate (k range: - 0.01, 0.43).

CONCLUSIONS

AFs favoring benignity are not uncommon in LR-5 observations, but category downgrade is exceptional.

KEY POINTS

• Ancillary features favoring benignity are encountered in 5.6-12.3% of observations categorized as LR-5. • Category downgrade of LR-5 observations is very rare (0.6% of observations) in the presence of AFs favoring benignity due to the high prevalence (98-99%) of ancillary features favoring malignancy in LR-5 observations. • The inter-reader agreement of ancillary features favoring benignity is poor to moderate (k range: - 0.01, 0.43) in readers with different levels of experience.

Hepatocarcinogenesis: Radiology-Pathology Correlation

In the background of chronic liver disease, hepatocellular carcinoma develops via a complex, multistep process called hepatocarcinogenesis. This article reviews the causes contributing to the process. Emphasis is made on the imaging manifestations of the pathologic changes seen at many stages of hepatocarcinogenesis, from regenerative nodules to dysplastic nodules and then to hepatocellular carcinoma.

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

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

Enhancing capsule in hepatocellular carcinoma: intra-individual comparison between CT and MRI with extracellular contrast agent

PURPOSE

The purpose of this study was to compare the value of contrast-enhanced computed tomography (CT) to that of magnetic resonance imaging obtained with extracellular contrast agent (ECA-MRI) for the diagnosis of a tumor capsule in hepatocellular carcinoma (HCC) using histopathologic findings as the standard of reference.

MATERIALS AND METHODS

This retrospective study included patients with pathologically-proven resected HCCs with available preoperative contrast-enhanced CT and ECA-MRI examinations. Two blinded radiologists independently reviewed contrast-enhanced CT and ECA-MRI examinations to assess the presence of an enhancing capsule. The histopathological analysis of resected specimens was used as reference for the diagnosis of a tumor capsule. The sensitivity and specificity of CT and ECA-MRI for the diagnosis of a tumor capsule were determined, and an intra-individual comparison of imaging modalities was performed using McNemar test. Inter-reader agreement was assessed using Kappa test.

RESULTS

The study population included 199 patients (157 men, 42 women; mean age: 61.3 ± 13.0 [SD] years) with 210 HCCs (mean size 56.7 ± 43.7 [SD] mm). A tumor capsule was present in 157/210 (74.8%) HCCs at histopathologic analysis. Capsule enhancement was more frequently visualized on ECA-MRI (R1, 68.6%; R2, 71.9%) than on CT (R1, 44.3%, P < 0.001; R2, 47.6%, P < 0.001). The sensitivity of ECA-MRI was better for the diagnosis of histopathological tumor capsule (R1, 76.4%; R2, 79.6%; P < 0.001), while CT had a greater specificity (R1, 84.9%; R2, 83.0%; P < 0.001). Inter-reader agreement was moderate both on CT (kappa = 0.55; 95% confidence interval [CI]: 0.43-0.66) and ECA-MRI (kappa = 0.57; 95% CI: 0.45-0.70).

CONCLUSION

Capsule enhancement was more frequently visualized on ECA-MRI than on CT. The sensitivity of ECA-MRI was greater than that of CT, but the specificity of CT was better than that of ECA-MRI.

Should Threshold Growth Be Considered a Major Feature in the Diagnosis of Hepatocellular Carcinoma Using LI-RADS?

OBJECTIVE

Based on the Liver Imaging Reporting and Data System version 2018 (LI-RADS, v2018), this study aimed to analyze LR-5 diagnostic performance for hepatocellular carcinoma (HCC) when threshold growth as a major feature is replaced by a more HCC-specific ancillary feature, as well as the frequency of threshold growth in HCC and non-HCC malignancies and its association with tumor size.

MATERIALS AND METHODS

This retrospective study included treatment-naive patients who underwent gadoxetate disodium-enhanced MRIs for focal hepatic lesions and surgery between January 2009 and December 2016. The frequency of major and ancillary features was evaluated for HCC and non-HCC malignancies, and the LR-category was assessed. Ancillary features that were significantly more prevalent in HCC were then used to either replace threshold growth or were added as additional major features, and the diagnostic performance of the readjusted LR category was compared to the LI-RADS v2018.

RESULTS

A total of 1013 observations were analyzed. Unlike arterial phase hyperenhancement, washout, or enhancing capsule which were more prevalent in HCCs than in non-HCC malignancies (521/616 vs. 18/58, 489/616 vs. 19/58, and 181/616 vs. 5/58, respectively; p < 0.001), threshold growth was more prevalent in non-HCC malignancies than in HCCs (11/23 vs. 17/119; p < 0.001). The mean size of non-HCC malignancies showing threshold growth was significantly smaller than that of non-HCC malignancies without threshold growth (22.2 mm vs. 42.9 mm, p = 0.040). Similar results were found for HCCs; however, the difference was not significant (26.8 mm vs. 33.1 mm, p = 0.184). Additionally, Fat-in-nodule was more frequent in HCCs than in non-HCC malignancies (99/616 vs. 2/58, p = 0.010). When threshold growth and fat-in-nodule were considered as ancillary and major features, respectively, LR-5 sensitivity (73.2% vs. 73.9%, p = 0.289) and specificity (98.2% vs. 98.5%, p > 0.999) were comparable to the LI-RADS v2018.

CONCLUSION

Threshold growth is not a significant diagnostic indicator of HCC and is more common in non-HCC malignancies. The diagnostic performance of LR-5 was comparable when threshold growth was recategorized as an ancillary feature and replaced by a more HCC-specific ancillary feature.

LI-RADS v2018: how to appropriately use ancillary features in category adjustment from intermediate probability of malignancy (LR-3) to probably HCC (LR-4) on gadoxetic acid-enhanced MRI

OBJECTIVES

To determine the appropriate use of ancillary features (AFs) in upgrading LI-RADS category 3 (LR-3) to category 4 (LR-4) for hepatic nodules on gadoxetic acid-enhanced MRI.

METHODS

We retrospectively analyzed MRI features of solid hepatic nodules (≤ 30 mm) categorized as LR-3/4 on gadoxetic acid-enhanced MRI. In LI-RADS diagnostic table-based-LR-3 observations, logistic regression analyses were performed to identify AFs suggestive of hepatocellular carcinomas (HCCs) rather than non-malignant nodules. Using McNemar's test, the sensitivities and specificities of the final-LR-4 category for HCC diagnosis were compared according to the principles of AF application in category adjustment.

RESULTS

A total of 336 hepatic nodules (191 HCCs; 145 non-malignant) in 252 patients were evaluated. Based on major HCC features, 248 nodules (123 HCCs) were assigned as table-based-LR-3 and 88 nodules (68 HCCs) as table-based-LR-4. In table-based-LR-3 observations, mild-moderate T2 hyperintensity was identified as an independent predictor of HCC as opposed to non-malignant nodules (odds ratio = 3.01, p = 0.002). For HCC diagnosis, different criteria of final-LR-4: only table-based-LR-4, allowing category upgrade using only T2 hyperintensity, or using any AFs favoring malignancy resulted in sensitivities of 35.6% (68/191), 53.9% (103/191), and 88.5% (169/191), and specificities of 86.2% (125/145), 75.9% (110/145), and 21.4% (31/145), respectively, which differed from each other (all p < 0.001).

CONCLUSIONS

While the application of MRI AF in LI-RADS category adjustment increases the sensitivity of LR-4 category for HCC diagnosis, it is accompanied by a significant decrease in specificity. Mild-moderate T2 hyperintensity, a significant AF indicative of HCC, may be more appropriate for upgrading LR-3 to LR-4.

KEY POINTS

• When upgrading from LR-3 to LR-4 using any MRI ancillary features favoring malignancy, LR-4 sensitivity increases but specificity decreased for HCC diagnosis. • By upgrading LR-3 to LR-4 based on MRI ancillary features found to suggest HCC rather than non-malignant nodules in multivariate analysis (i.e., mild-moderate T2 hyperintensity), LR-4 demonstrated a more balanced sensitivity and specificity for HCC diagnosis (53.9% and 75.9%, respectively).

Meta-Analysis of the Accuracy of Abbreviated Magnetic Resonance Imaging for Hepatocellular Carcinoma Surveillance: Non-Contrast versus Hepatobiliary Phase-Abbreviated Magnetic Resonance Imaging

Simple Summary

Ultrasonography is recommended as a standard surveillance modality, but the performance of surveillance ultrasound for detecting early-stage hepatocellular carcinoma (HCC) is limited. Motivated to provide a more sensitive method, abbreviated magnetic resonance imaging (AMRI) protocols have been introduced for HCC surveillance. We aimed to systematically determine the diagnostic performance of surveillance AMRI for detecting HCC. This meta-analysis of 10 studies comprising 1547 patients found that the pooled sensitivity and specificity of surveillance AMRI for detecting HCC were 86% and 96%, respectively. Hepatobiliary phase contrast-enhanced AMRI showed significantly higher sensitivities for detecting HCC than non-contrast AMRI (87% vs. 82%), but significantly lower specificities (93% vs. 98%). Therefore, surveillance AMRI had overall good diagnostic performance for detecting HCC and might be clinically useful for HCC surveillance. In addition, AMRI protocol should be selected with consideration of the advantages and disadvantages of each protocol.

Abstract

We aimed to determine the performance of surveillance abbreviated magnetic resonance imaging (AMRI) for detecting hepatocellular carcinoma (HCC), and to compare the performance of surveillance AMRI according to different protocols. Original research studies reporting the performance of surveillance AMRI for the detection of HCC were identified in MEDLINE, EMBASE, and Cochrane databases. The pooled sensitivity and specificity of surveillance AMRI were calculated using a hierarchical model. The pooled sensitivity and specificity of contrast-enhanced hepatobiliary phase (HBP)-AMRI and non-contrast (NC)-AMRI were calculated and compared using bivariate meta-regression. Ten studies, including 1547 patients, reported the accuracy of surveillance AMRI. The pooled sensitivity and specificity of surveillance AMRI for detecting any-stage HCC were 86% (95% confidence interval (CI), 80–90%; I² = 0%) and 96% (95% CI, 93–98%; I² = 80.5%), respectively. HBP-AMRI showed a significantly higher sensitivity for detecting HCC than NC-AMRI (87% vs. 82%), but significantly lower specificity (93% vs. 98%) (p = 0.03). Study quality and MRI magnet field strength were factors significantly associated with study heterogeneity (p ≤ 0.01). In conclusion, surveillance AMRI showed good overall diagnostic performance for detecting HCC. HBP-AMRI had significantly higher sensitivity for detecting HCC than NC-AMRI, but lower specificity.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

Up-to-Date Role of CT/MRI LI-RADS in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of mortality worldwide and a major healthcare burden in most societies. Computed tomography (CT) and magnetic resonance imaging (MRI) play a pivotal role in the medical care of patients with or at risk for hepatocellular carcinoma (HCC). When stringent imaging criteria are fulfilled, CT and MRI allow for diagnosis, staging, and assessment of response to treatment, without the need for invasive workup, and can inform clinical decision making. Owing to the central role of these imaging modalities in HCC management, standardization is essential to facilitate proper imaging technique, accurate interpretation, and clear communication among all stakeholders in both the clinical practice and research settings. The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system that provides standardization across the continuum of HCC imaging, including ordinal probabilistic approach for reporting that directs individualized management. This review discusses the up-to-date role of CT and MRI in HCC imaging from the LI-RADS perspective. It also provides a glimpse into the future by discussing how advances in knowledge and technology are likely to enrich the LI-RADS approach.

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

Simple Summary

The LI-RADS system is nowadays the mainstream system used in classifying liver nodules in cirrhotic liver according to their risk of malignancy. Two main LI-RADS documents have been released—the CEUS LI-RADS v2017 document, and the CT/MRI LI-RADS v2018 document. In some circumstances, a nodule can be differently classified when using CEUS versus when using CT or MRI. In this paper, we also focus on the existing similitudes between the two documents but, essentially, on the differences between the two main documents and the complementarities between imaging techniques in characterizing liver nodules in cirrhotic livers. Awareness of the complementarity of imaging techniques may lead to an improvement in the characterization and classification of liver nodules and will reduce the number of liver biopsies. This paper proposes practical solutions in order to better classify and manage observations or nodules detected in cirrhotic livers.

Abstract

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

Can Risk Stratification Based on Ultrasound Elastography of Background Liver Assist CEUS LI-RADS in the Diagnosis of HCC?

Objective

To explore whether risk stratification based on ultrasound elastography of liver background assists contrast-enhanced ultrasound liver imaging reporting and data system (CEUS LI-RADS) in diagnosing HCC.

Materials and Methods

In total, 304 patients with focal liver lesions (FLLs) confirmed by pathology underwent CEUS and ultrasound elastography were included in this retrospective study. Patients with chronic hepatitis B (CHB, n=193) and non-CHB (n=111) were stratified by four liver stiffness measurement (LSM) thresholds. A LI-RADS category was assigned to FLLs using CEUS LI-RADS v2017. The diagnostic performance was assessed with the AUC, sensitivity, specificity, PPV, and NPV.

Results

The mean background liver stiffness of HCC patients with CHB, HCC patients without CHB and non-HCC patients without CHB were 9.72 kPa, 8.23 kPa and 4.97 kPa, respectively. The AUC, sensitivity, specificity and PPV of CEUS LI-RADS for HCC in CHB patients with LSM ≥ 5.8 kPa, ≥ 6.8 kPa, ≥ 9.1 kPa, and ≥ 10.3 kPa were high, with corresponding values of 0.745 to 0.880, 94.2% to 95.3%, 81.3% to 85.7%, and 98.1% to 98.8%, respectively. Higher AUC and specificity for HCC was observed in non-CHB patients with LSM ≥ 9.1 kPa and ≥ 10.3 kPa compared to non-CHB patients with LSM ≥ 5.8 kPa and ≥ 6.8 kPa, with corresponding values of0.964/1.000 vs 0.590/0.580, and 100%/100% vs 60%/70%, respectively.

Conclusion

CEUS LI-RADS has a good diagnostic performance in CHB patients regardless of the background liver stiffness. Furthermore, CEUS LI-RADS can be applied for non-CHB patients with a LSM ≥ 9.1 kPa.

Is There a Difference Between LI-RADS 3 to LI-RADS 5 Progression Assessment Using CT Versus MR? A Retrospective, Single-Center, Longitudinal Study of Patients Who Underwent 5082 Radiologic Examinations for Surveillance of Hepatocellular Carcinoma Over a 43-Month Period

OBJECTIVE

The Liver Imaging Reporting and Data System (LI-RADS) has been widely applied to CT and MR liver observations in patients at high-risk for hepatocellular carcinoma (HCC). We investigated the impact of CT vs MR in upgrading LI-RADS 3 to LI-RADS 5 observations using a large cohort of high-risk patients.

METHODS

We performed a retrospective, longitudinal study of CT and MR radiographic reports (June 2013 - February 2017) with an assigned LI-RADS category. A final population of 757 individual scans and 212 high-risk patients had at least one LI-RADS 3 observation. Differences in observation time to progression between modalities were determined using uni- and multivariable analysis.

RESULTS

Of the 212 patients with a LI-RADS 3 observation, 52 (25%) had progression to LI-RADS 5. Tp ranged from 64 - 818 days (median: 196 days). One hundred and three patients (49%) had MR and 109 patients (51%) had CT as their index study. Twenty-four patients with an MR index exam progressed to LI-RADS 5 during the follow-up interval, with progression rates of 22% (CI:13%-30%) at 1 year and 29% (CI:17%-40%) at 2 years. Twenty-eight patients with a CT index exam progressed to LI-RADS 5 during follow-up, with progression rates of 26% (CI:16%-35%) at 1 year and 31% (CI:19%-41%) at 2 years. Progression rates were not significantly different between patients whose LI-RADS 3 observation was initially diagnosed on MR vs CT (HR: 0.81, P = 0.44).

DISCUSSION

MR and CT modalities are comparable for demonstrating progression from LI-RADS 3 to 5 for high risk patients.

Increasing the sensitivity of LI-RADS v2018 for diagnosis of small (10-19 mm) HCC on extracellular contrast-enhanced MRI

PURPOSE

To evaluate whether the LI-RADS v2018 LR-5 criteria can be modified to increase sensitivity without reducing specificity for diagnosing small (10-19 mm) HCC.

METHODS

167 consecutive high-risk patients with 174 small observations reported clinically on extracellular contrast-enhanced MRI from 2014 to 2018 were retrospectively studied. The best available reference standard was applied for each observation. Blinded to the reference standard, two radiologists scored LI-RADS imaging features retrospectively and assigned each observation a LI-RADS category using LI-RADS v2018 and each of four modified LI-RADS versions (mLI-RADS I to IV) with successively more expansive LR-5 criteria. Per-observation sensitivity and specificity of LR-5 for small HCC using each version were assessed. Each modified version was compared to v2018 (McNemar test).

RESULTS

The 174 observations included 135 HCC, 8 non-HCC malignancies, and 31 benign entities. Using LI-RADS v2018, LR-5 provided 70% (both readers) sensitivity and 95% (both readers) specificity for small HCC. Expanding the LR-5 criteria to include nonrim APHE plus at least one additional major feature (mLI-RADS I) or no APHE plus at least two additional major features (mLI-RADS II) significantly increased sensitivity (reader 1/reader 2: 75%/75% vs. 70%, p = 0.016/0.031; 78%/79% vs. 70%, p = 0.001/0.001) without significantly reducing specificity (reader 1/reader 2: 90%/92% vs. 95%, p = 0.500/1.000 for both). mLI-RADS III and IV further increased sensitivity (reader 1/reader 2: 80%/81% vs. 70%, p < 0.001/< 0.001; 94%/92% vs. 70, p < 0.001/< 0.001) but with trend-level (reader 1/reader 2: 85%/80% vs. 95%, p = 0.125/0.063) or significant (reader 1/reader 2: 64%/62% vs. 95%, p < 0.001/< 0.001) specificity reductions.

CONCLUSIONS

Expanding the v2018 LR-5 criteria to include nonrim APHE plus at least one additional major feature or no APHE plus at least two additional major features significantly increases sensitivity without significantly reducing specificity for small HCC. Confirmation is warranted in multi-center prospective studies.

Uptake of gadoxetic acid in hepatobiliary phase magnetic resonance imaging and transporter expression in hypovascular hepatocellular nodules

AIMS

To evaluate the association between contrast patterns on gadoxetic acid-enhanced hepatobiliary phase (HBP) MR images and transporter expression in surgically resected hypovascular hepatocellular nodules including early hepatocellular carcinomas (HCCs).

METHODS

Forty-two hypovascular hepatic nodules and 43 hypervascular HCCs as a control were included in this retrospective study. Contrast of the nodules on HBP images was graded as hypo-, iso-, or hyperintense. Histopathological assessment was performed in the context of multistep hepatocarcinogenesis. Immunohistochemical staining of organic anion transporter 1B3 (OATP1B3) and multidrug resistance protein 2 (MRP2) was performed. Cramer's coefficient was used to determine the linear relationship between contrast grades and transporter expression, and the Cochran-Armitage trend test was used to determine the relationship between transporter expression and progression of multistep hepatocarcinogenesis.

RESULTS

Moderate linear relationships between contrast grades and OATP1B3 expression were observed for both hypo- and hypervascular nodules. OATP1B3 expression was negatively correlated with the progression of multistep hepatocarcinogenesis. MRP2 expression was not associated with the contrast grades or histopathological results.

CONCLUSION

OATP1B3 expression was associated with contrast grades of hepatocellular nodules observed in HBP image of gadoxetic acid-enhanced MRI in the hypovascular hepatocellular nodules and was negatively correlated with hepatocarcinogenesis.