Added Value of a Gadoxetic Acid-enhanced Hepatocyte-phase Image to the LI-RADS System for Diagnosing Hepatocellular Carcinoma

Is there added value of the hepatobiliary phase of MRI with hepatobiliary contrast agents for hepatocellular carcinoma diagnosis? A meta-analysis

Purpose

So far, there have been published several meta-analyses which focused on hepatocellular carcinoma (HCC) detection with hepatobiliary phase (HBP) contrast agents. However, only a few of them aimed at establishing whether there is any added value of the HBP itself for HCC diagnosis. To answer the question, we performed a systematic literature search with the time limit going back to 2010.

Material and methods

True positive, false positive, false negative, and true negative values with and without the HBP were extracted from the included studies. Pooled sensitivities and specificities with and without the HBP were calculated and summary receiver operating characteristics curves were drawn to assess the diagnostic performance of the studies with and without the HBP.

Results

A total of 13 studies were included involving 1184 HCC lesions. In 13 studies without the HBP, the pooled sensitivity, specificity, and area under the curve (AUC) were 0.83, 0.89 and 0.94 respectively. In 13 studies with the HBP, the pooled sensitivity, specificity and AUC were 0.91, 0.85 and 0.98 respectively.

Conclusions

We found no statistically significant differences in sensitivities between studies with and without the HBP (p = 0.1651).

Evidence Supporting Diagnostic Value of Liver Imaging Reporting and Data System for CT- and MR Imaging-based Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

Background

Based on the Liver Imaging Data and Reporting System (LI-RADS) guidelines, Hepatocellular Carcinoma (HCC) can be diagnosed using imaging criteria in patients at risk of HCC.

Objective

This study aimed to assess the diagnostic value of LI-RADS in high-risk patients with HCC.

Material and Methods

This systematic review is conducted on international databases, including Google Scholar, Web of Science, PubMed, Embase, PROQUEST, and Cochrane Library, with appropriate keywords. Using the binomial distribution formula, the variance of each study was calculated, and all the data were analyzed using STATA version 16. The pooled sensitivity and specificity were determined using a random-effects meta-analysis approach. Also, we used the chi-squared test and I2 index to calculate heterogeneity among studies, and Funnel plots and Egger tests were used for evaluating publication bias.

Results

The pooled sensitivity was estimated at 0.80 (95% CI 0.76-0.84). According to different types of Liver Imaging Reporting and Data Systems (LI-RADS), the highest pooled sensitivity was in version 2018 (0.83 (95% CI 0.79-0.87) (I2: 80.6%, P of chi 2 test for heterogeneity <0.001 and T2: 0.001). The pooled specificity was estimated as 0.89 (95% CI 0.87-0.92). According to different types of LI-RADS, the highest pooled specificity was in version 2014 (93.0 (95% CI 89.0-96.0) (I2: 81.7%, P of chi 2 test for heterogeneity <0.001 and T2: 0.001).

Conclusion

LI-RADS can assist radiologists in achieving the required sensitivity and specificity in high-risk patients suspected to have HCC. Therefore, this strategy can serve as an appropriate tool for identifying HCC.

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.

Diagnostic Values of the Liver Imaging Reporting and Data System in the Detection and Characterization of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

This review was undertaken to assess the diagnostic value of the Liver Imaging Reporting and Data System (LI-RADS) in patients with a high risk of hepatocellular carcinoma (HCC). Google Scholar, PubMed, Web of Science, Embase, PROQUEST, and Cochrane Library, as the international databases, were searched with appropriate keywords. Using the binomial distribution formula, the variance of all studies was calculated, and using Stata version 16 (StataCorp LLC, College Station, TX, USA), the obtained data were analyzed. Using a random-effect meta-analysis approach, we determined the pooled sensitivity and specificity. Utilizing the funnel plot and Begg's and Egger's tests, we assessed publication bias. The results exhibited pooled sensitivity and pooled specificity of 0.80% and 0.89%, respectively, with a 95% confidence interval (CI) of 0.76-0.84 and 0.87-0.92, respectively. The 2018 version of LI-RADS showed the greatest sensitivity (0.83%; 95% CI 0.79-0.87; I ² = 80.6%; P < 0.001 for heterogeneity; T ² = 0.001). The maximum pooled specificity was detected in LI-RADS version 2014 (American College of Radiology, Reston, VA, USA; 93.0%; 95% CI 89.0-96.0; I ² = 81.7%; P < 0.001 for heterogeneity; T ² = 0.001). In this review, the results of estimated sensitivity and specificity were satisfactory. Therefore, this strategy can serve as an appropriate tool for identifying 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.

Predictors of changes in preoperative tumor stage between dynamic computed tomography and gadoxetate disodium-enhanced magnetic resonance imaging for hepatocellular carcinoma

BACKGROUND/PURPOSE

Gadoxetate disodium-enhanced magnetic resonance imaging (EOB-MRI) has a higher diagnostic accuracy for hepatocellular carcinoma (HCC) than computed tomography (CT). However, indications for performing EOB-MRI after dynamic CT are not well defined. Therefore, we investigated the clinical factors associated with changes in the preoperative tumor stage between dynamic CT and EOB-MRI.

METHODS

A prospective cohort was conducted from January 2014 to December 2017. 156 adult patients with clinical suspicion of HCC before liver resection were enrolled and we retrospectively reviewed the images. The tumor staging was evaluated by dynamic CT and then EOB-MRI subsequently according to the TNM staging system. The changes in tumor stage between two modalities were identified, and the associated clinical factors were analyzed.

RESULTS

A total of 99 patients were analyzed after excluding 57 patients. 20 patients (20.2%) had changes in tumor stage between dynamic CT and EOB-MRI. The change occurred only in early stage (T1 and T2 lesions) based on dynamic CT initially. Furthermore, in univariate and multivariate analyses, albumin-bilirubin (ALBI) grade 2 and log alpha-fetoprotein (AFP) levels were associated with changes in tumor staging by EOB-MRI than those without (50% vs. 9.9%, p < 0.001 and 2.04 ± 1.35 vs. 1.40 ± 1.16, p = 0.038, respectively). Patients with changes in tumor stage also exhibited higher 1-year recurrence rate and shorter recurrence-free survival.

CONCLUSION

Changes in preoperative tumor stage between dynamic CT and EOB-MRI were associated with CT-defined early stage, ALBI grades, higher log AFP levels, and early recurrence.

Diagnostic performance of CT versus MRI Liver Imaging Reporting and Data System category 5 for hepatocellular carcinoma: a systematic review and meta-analysis of comparative studies

OBJECTIVE

To compare the performance of Liver Imaging Reporting and Data System category 5 (LR-5) for diagnosing HCC between CT and MRI using comparative studies.

METHODS

The MEDLINE and EMBASE databases were searched from inception to April 21, 2021, to identify studies that directly compare the diagnostic performance of LR-5 for HCC between CT and MRI. A bivariate random-effects model was fitted to calculate the pooled per-observation sensitivity and specificity of LR-5 of each modality, and compare the pooled estimates of paired data. Subgroup analysis was performed according to the MRI contrast agent.

RESULTS

Seven studies with 1145 observations (725 HCCs) were included in the final analysis. The pooled per-observation sensitivity of LR-5 for diagnosing HCC was higher using MRI (61%; 95% confidence interval [CI], 43-76%; I² = 95%) than CT (48%; 95% CI, 31-65%; I² = 97%) (p < 0.001). The pooled per-observation specificities of LR-5 did not show statistically significant difference between CT (96%; 95% CI, 92-98%; I² = 0%) and MRI (93%; 95% CI, 88-96%; I² = 16%) (p = 0.054). In the subgroup analysis, extracellular contrast agent-enhanced MRI showed significantly higher pooled per-observation sensitivity than gadoxetic acid-enhanced MRI for diagnosing HCC (73% [95% CI, 55-85%] vs. 55% [95% CI, 39-70%]; p = 0.007), without a significant difference in specificity (93% [95% CI, 80-98%] vs. 94% [95% CI, 87-97%]; p = 0.884).

CONCLUSIONS

The LR-5 of MRI showed significantly higher pooled per-observation sensitivity than CT for diagnosing HCC. The pooled per-observation specificities of LR-5 were comparable between the two modalities.

KEY POINTS

• The pooled sensitivity of LR-5 using MRI was higher than that using CT (61% versus 48%), but the pooled specificities of LR-5 were not significantly different between CT and MRI (96% versus 93%). • Subgroup analysis according to the MRI contrast media showed a significantly higher pooled per-observation sensitivity using ECA-enhanced MRI than with EOB-enhanced MRI (73% versus 55%), and comparable specificities (93% versus 94%). • Although LI-RADS provides a common diagnostic algorithm for CT or MRI, the per-observation performance of LR-5 can be affected by the imaging modality as well as the MRI contrast agent.

Diagnostic Performance of LI-RADS Version 2018 for Primary Liver Cancer in Patients With Liver Cirrhosis on Enhanced MRI

Purpose

The study evaluated the diagnostic performance of the Liver Imaging Reporting and Data System (LI-RADS) version 2018 for differentiating hepatocellular carcinoma (HCC) from primary liver cancer in patients with liver cirrhosis based on the updated 2019 WHO classification.

Materials and Methods

From 2016 to 2021, 300 patients with surgically confirmed primary liver cancer (PLC) and liver cirrhosis based on the updated 2019 WHO classification were eligible for this retrospective study (100 cases in each of three groups including HCC, ICC, and cHCC-CCA). Two radiologists were blinded to the final diagnosis and independently assigned an LI-RADS category to each liver nodule. The diagnostic performances of the LR-5 category (definitely HCC), and the LR-M category (probably or definitely malignant, but not specific for HCC) were calculated in overall and small observations (<20 mm). Comparisons between groups of categorical variables were performed by one-way analysis of variance and the Chi-squared or Fisher’s exact test.

Results

The mean age of 300 patients (226 men and 74 women) was 57.40 ± 11.05 years. The sensitivity and specificity of the LR-5 category for differentiating HCCs from other primary liver cancers were 81% (81 of 100) and 82% (164 of 200), respectively. The LR-M category had a sensitivity of 63% (126 of 200) for diagnosing non-HCCs (ICCs and cHCC-CCAs), with a specificity of 90% (90 of 100). The LR-5 category had a sensitivity of 82.5% (33 of 40) for diagnosing HCCs in small observations (<20 mm) with a specificity of 76.6% (59 of 77). On the contrary, LR-M demonstrated slightly higher specificity (93.8%) and sensitivity (73.8%) for diagnosing non-HCCs with tumor size <20 mm.

Conclusion

The LR-5 category as well as the LR-M category of Liver Imaging Reporting and Data System (LI-RADS) version 2018 can effectively distinguish hepatocellular carcinoma from other primary hepatic malignancies in patients with liver cirrhosis, especially for small observations (<20 mm).

Do transition and hepatobiliary phase hypointensity improve LI-RADS categorization as an alternative washout: a systematic review and meta-analysis

OBJECTIVE

The definition of washout in gadoxetate disodium-enhanced MRI (Gd-EOB-MRI) is controversial. The current Liver Imaging Reporting and Data System (LI-RADS) defines washout only in the portal venous phase on Gd-EOB-MRI, leading to low diagnostic sensitivity for HCC. We performed a meta-analysis to compare the diagnostic performance of Gd-EOB-MRI using conventional (cWO) and modified (mWO) definitions of washout.

METHODS

The PubMed and EMBASE databases were searched to identify studies published between January 1, 2010, and August 1, 2021, that compared the diagnostic performance of cWO and mWO for HCC. The mWOs added transition phase (TP) hypointensity (mWO-1), hepatobiliary phase (HBP) hypointensity (mWO-2), or both (mWO-3). The pooled sensitivity and specificity were calculated using a bivariate random-effects model. Study heterogeneity was explored by subgroup analysis and meta-regression analysis.

RESULTS

Ten comparative studies with 2391 patients were included. Compared to cWO, the overall mWO yielded significantly higher sensitivity (71% vs. 81%, p = 0.00) and lower specificity (97% vs. 93%, p = 0.01) for diagnosing HCC. The area under the curve (AUC) was 0.90 and 0.94 for the cWO and mWO, respectively. Regarding the three types of mWOs, mWO-2 showed the highest sensitivity (85%) and specificity (96%) for diagnosing HCC. mWO-2 achieved the highest AUC (0.97), followed by mWO-1 (0.90), and mWO-3 (0.89). Average reviewer experience and scanner field strength were significantly associated with study heterogeneity (p < 0.05).

CONCLUSIONS

Inclusion of TP and HBP hypointensity in the definition of washout improved the sensitivity with slightly lower specificity for diagnosing HCC in LI-RADS.

KEY POINTS

• Compared to the conventional definition of washout, studies using a modified definition had higher sensitivity (71% vs. 81%) but lower specificity (97% vs. 93%) in LI-RADS for the diagnosis of HCC. • Hepatobiliary phase hypointensity may be a preferred alternative washout for HCC diagnosis with the highest area under the curve. • Studies with experienced reviewer or 3.0T MRI showed higher sensitivity and lower specificity for diagnosing HCC when using modified washout (p < 0.05).

[Clinical relevance of the new S3 guideline on hepatocellular carcinoma and biliary tract cancer for practitioners]

The update of the S3 German guideline for the management of the hepatocellular carcinoma and biliary tract cancer contains a comprehensive revision of the guideline for hepatocellular carcinoma and establishes a new guideline for biliary tract cancer. In recent years several studies have been conducted to improve diagnostic and therapeutic options for liver cancer. Magnetic resonance imaging (MRI) and biopsy are important for the diagnosis of hepatocellular carcinoma or cholangiocarcinoma. This guideline shows the progress in the treatment options for hepatocellular carcinoma, including advances in liver transplantation, bridging and downstaging. For cholangiocarcinoma there is a focus on interventional treatment and resection. This guideline also emphasizes the need of molecular diagnostics and the resulting treatment options in targeted therapy.

[Small hepatocellular carcinoma : Diagnostics according to guidelines and established in the clinical setting]

CLINICAL/METHODICAL ISSUE

The diagnosis of hepatocellular carcinoma (HCC)-especially the characterization of small lesions <2 cm-continues to be a radiological challenge.

STANDARD RADIOLOGICAL METHODS

In the current S3 guideline on diagnosis and therapy of HCC, contrast-enhanced imaging examinations, such as contrast-enhanced ultrasonography (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI), are still the diagnostic standard.

METHODOLOGICAL INNOVATIONS

HCC in the cirrhotic liver should be diagnosed by its typical contrast-enhanced pattern in the MRI. In addition, the use of quality assurance instruments such as LI-RADS (Liver Imaging Reporting and Data System) contributes to the desired consistency of findings, even with small ambiguous findings.

PERFORMANCE

Many studies have shown that the LI-RADS classification reflects the likelihood of HCC and other malignant liver lesions.

ACHIEVEMENTS

Guidelines and quality assurance instruments contribute to a more precise diagnosis in patients with suspected HCC.

PRACTICAL RECOMMENDATIONS

A guideline-compliant diagnostic algorithm and the LI-RADS should be used across the board for accurate HCC diagnostics.

Comparison of Gadobenate-Enhanced MRI and Gadoxetate-Enhanced MRI for Hepatocellular Carcinoma Detection Using LI-RADS Version 2018: A Prospective Intraindividual Randomized Study

Background: Gadobenate and gadoxetate demonstrate different degrees of intracellular accumulation within hepatocytes, potentially impacting these agents' relative performance for hepatocellular carcinoma (HCC) diagnosis. Objective: To perform an intraindividual comparison of gadobenate-enhanced MRI and gadoxetate-enhanced MRI for detection of HCC, and to assess the impact of inclusion of hepatobiliary phase images on HCC detection for both agents. Methods: This prospective study enrolled 126 patients (112 men, 14 women; mean age 52.3 years) at high risk for HCC who consented to undergo two 3-T liver MRI examinations [one using gadobenate (0.05 mmol/kg), one using gadoxetate (0.025 mmol/kg)], separated by 7-14 days. The order of the two contrast agents was randomized. All examinations included post-contrast dynamic and hepatobiliary phase images (120 minutes for gadobenate; 20 minutes for gadoxetate). Three radiologists independently reviewed the gadobenate and gadoxetate examinations in separate sessions and recorded the location of detected observations. Observations were classified using LI-RADS version 2018 and using a LI-RADS modification whereby hepatobiliary phase hypointensity may upgrade observations from LR-4 to LR-5. Observations classified as LR-5 were considered positive interpretations for HCC. Diagnostic performance for histologically confirmed HCC (n=96) was assessed. Results: Across readers, sensitivity for HCC using dynamic images alone was 74.0%-80.2% for gadobenate versus 54.2%-67.7% for gadoexetate and using dynamic and hepatobiliary phase images was 82.1%-87.4% for gadobenate versus 66.3%-81.1% for gadoxetate. For HCCs measuring 1.0-2.0 cm, sensitivity using dynamic images alone was 61.9% (all readers) for gadobenate versus 38.1%-57.1% for gadoxetate and using dynamic and hepatobiliary phase images was 76.2%-85.7% for gadobenate versus 52.4%-61.9% for gadoxetate. PPV for HCC ranged from 88.6%-97.4% across readers, agents, and image sets. Conclusion: Sensitivity for HCC was higher for gadobenate than for gadoxetate, whether using dynamic images alone or dynamic and hepatobiliary phase images; the improved sensitivity using gadobenate was more pronounced for small HCCs. While hepatobiliary phase images improved sensitivity for both agents, sensitivity of gadobenate using dynamic images alone compared favorably with that of gadoxetate using dynamic and hepatobiliary phase images. Clinical Impact: The findings support gadobenate as a preferred agent over gadoxetate when performing liver MRI in patients at high risk for HCC.

Inter-reader reliability of CT Liver Imaging Reporting and Data System according to imaging analysis methodology: a systematic review and meta-analysis

OBJECTIVES

To establish inter-reader reliability of CT Liver Imaging Reporting and Data System (LI-RADS) and explore factors that affect it.

METHODS

MEDLINE and EMBASE databases were searched from January 2014 to March 2020 to identify original articles reporting the inter-reader reliability of CT LI-RADS. The imaging analysis methodology of each study was identified, and pooled intraclass correlation coefficient (ICC) or kappa values (κ) were calculated for lesion size, major features (arterial-phase hyperenhancement [APHE], nonperipheral washout [WO], and enhancing capsule [EC]), and LI-RADS categorization (LR) using random-effects models. Subgroup analyses of pooled κ were performed for the number of readers, average reader experience, differences in reader experience, and LI-RADS version.

RESULTS

In the 12 included studies, the pooled ICC or κ of lesion size, APHE, WO, EC, and LR were 0.99 (0.96-1.00), 0.69 (0.58-0.81), 0.67 (0.53-0.82), 0.65 (0.54-0.76), and 0.70 (0.59-0.82), respectively. The experience and number of readers varied: studies using readers with ≥ 10 years of experience showed significantly higher κ for LR (0.82 vs. 0.45, p = 0.01) than those with < 10 years of reader experience. Studies with multiple readers including inexperienced readers showed significantly lower κ for APHE (0.55 vs. 0.76, p = 0.04) and LR (0.45 vs. 0.79, p = 0.02) than those with all experienced readers.

CONCLUSIONS

CT LI-RADS showed substantial inter-reader reliability for major features and LR. Inter-reader reliability differed significantly according to average reader experience and differences in reader experience. Reported results for inter-reader reliability of CT LI-RADS should be understood with consideration of the imaging analysis methodology.

KEY POINTS

• The CT Liver Imaging Reporting and Data System (LI-RADS) provides substantial inter-reader reliability for three major features and category assignment. • The imaging analysis methodology varied across studies. • The inter-reader reliability of CT LI-RADS differed significantly according to the average reader experience and the difference in reader experience.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Application of Liver Imaging Reporting and Data System version 2018 ancillary features to upgrade from LR-4 to LR-5 on gadoxetic acid-enhanced MRI

OBJECTIVES

The current LR-5 criteria of Liver Imaging Reporting and Data System (LI-RADS) determined by only major features provide high specificity, but unsatisfactorily low sensitivity for the noninvasive diagnosis of hepatocellular carcinoma (HCC). This study aimed to identify significant ancillary features (AFs) in LI-RADS version 2018 and develop the upgraded LR-5 criteria to improve diagnostic performance on gadoxetic acid-enhanced magnetic resonance imaging (MRI).

METHODS

This retrospective study included 280 patients (366 observations including 281 HCCs) at high-risk for HCC who underwent gadoxetic acid-enhanced MRI between 2015 and 2017. Two readers evaluated major features and AFs for each observation and assigned a LI-RADS category. Independently significant AFs were identified through logistic regression analysis. Upgraded LR-5 criteria were developed by combining independently significant AFs with LR-4 assigned by major features alone. Sensitivities and specificities of the diagnostic criteria were compared using McNemar's test.

RESULTS

Two of the AFs favoring malignancy in general (mild-moderate T2 hyperintensity and hepatobiliary phase hypointensity) and two of the AFs favoring HCC in particular (nonenhancing "capsule" and mosaic architecture) were independently significant features for diagnosing HCC. By using the upgraded LR-5 criteria (LR-4 by major features alone + each aforementioned AF), sensitivities were significantly increased (69.4-76.9%) compared with the standard LR-5 (66.2%; all, p ≤ 0.004), whereas specificities (95.3-96.5%) were not significantly different (96.5%; all, p > 0.999).

CONCLUSIONS

Independently significant AFs may be used to upgrade from LR-4 to LR-5 to improve sensitivity without impairing specificity on gadoxetic acid-enhanced MRI.

KEY POINTS

• Independently significant AFs for HCC on gadoxetic acid-enhanced MRI were mild-moderate T2 hyperintensity, hepatobiliary phase hypointensity, nonenhancing "capsule," and mosaic architecture. • When LR-4 criteria by major features alone in combination with significant AFs were upgraded to LR-5, sensitivities were higher than the standard LR-5, without impairing specificity. • Independently significant ancillary features in Liver Imaging Reporting and Data System version 2018 may be used to upgrade from LR-4 to LR-5 to improve sensitivity without impairing specificity on gadoxetic acid-enhanced MRI.

Diagnostic performance of LI-RADS version 2018 in differentiating hepatocellular carcinoma from other hepatic malignancies in patients with hepatitis B virus infection

The diagnostic performance of the Liver Imaging Reporting and Data System (LI-RADS) in differentiating hepatocellular carcinoma (HCC) from other hepatic malignancies has not been investigated in Chinese patients with chronic liver disease from hepatitis B virus (HBV) infection. The aim of this study was to evaluate the accuracy of the LI-RADS version 2018 in differentiating HCC, intrahepatic cholangiocarcinoma (ICCA), and combined HCC-cholangiocarcinoma (cHCC-CCA) in Chinese patients with HBV infection. Seventy consecutive HBV-infected patients with ICCA (n = 48) or cHCC-CCA (n = 22) who underwent contrast-enhanced magnetic resonance imaging (CE-MRI) between 2006 and 2017 were enrolled along with a comparison cohort of 70 patients with HCC and CE-MRI-matched for tumor size (10-19 mm, 20-30 mm, 31-50 mm, and >50 mm). Imaging feature frequencies for each tumor type were compared using Fisher's exact test. The classification accuracy of LR-5 and LR-M was estimated for HCC versus non-HCC (ICCA and cHCC-CCA). The interobserver agreement was good for LI-RADS categories of HCC and moderate for non-HCC. After consensus read, 66 of 70 (94%) HCCs were categorized LR-5 (including tumor in vein [TIV] with LR-5), while 42 of 48 (88%) ICCAs and 13 of 22 (59%) cHCC-CCAs were categorized LR-M (including TIV with LR-M) (p < 0.001). Thus, assignment of LR-5 provided 94% sensitivity and 81% specificity for HCC. LR-M provided 79% sensitivity and 97% specificity for non-HCC (ICCA and cHCC-CCA); and the sensitivity and accuracy were lower in differentiating HCC from non-HCC (tumor size <20 mm). LI-RADS v2018 category 5 and M reliably differentiated HBV-related HCC from ICCA. However, a substantial proportion of cHCC-CCAs were categorized LR-5 rather than LR-M. While management is controversial for these combined tumors, accurate prospective differentiation is desired for optimal treatment.

Intraindividual Comparison between Gadoxetate-Enhanced Magnetic Resonance Imaging and Dynamic Computed Tomography for Characterizing Focal Hepatic Lesions: A Multicenter, Multireader Study

OBJECTIVE

To compare the diagnostic accuracy of dynamic computed tomography (CT) and gadoxetate-enhanced magnetic resonance imaging (MRI) for characterization of hepatic lesions by using the Liver Imaging Reporting and Data System (LI-RADS) in a multicenter, off-site evaluation.

MATERIALS AND METHODS

In this retrospective multicenter study, we evaluated 231 hepatic lesions (114 hepatocellular carcinomas [HCCs], 58 non-HCC malignancies, and 59 benign lesions) confirmed histologically in 217 patients with chronic liver disease who underwent both gadoxetate-enhanced MRI and dynamic CT at one of five tertiary hospitals. Four radiologists at different institutes independently reviewed all MR images first and the CT images 4 weeks later. They evaluated the major and ancillary imaging features and categorized each hepatic lesion according to the LI-RADS v2014. Diagnostic performance was calculated and compared using generalized estimating equations.

RESULTS

MRI showed higher sensitivity and accuracy than CT for diagnosing hepatic malignancies; the pooled sensitivities, specificities, and accuracies for categorizing LR-5/5V/M were 59.0% vs. 72.4% (CT vs. MRI; p < 0.001), 83.5% vs. 83.9% (p = 0.906), and 65.3% vs. 75.3% (p < 0.001), respectively. CT and MRI showed comparable capabilities for differentiating between HCC and other malignancies, with pooled accuracies of 79.9% and 82.4% for categorizing LR-M, respectively (p = 0.139).

CONCLUSION

Gadoxetate-enhanced MRI showed superior accuracy for categorizing LR-5/5V/M in hepatic malignancies in comparison with dynamic CT. Both modalities had comparable accuracies for distinguishing other malignancies from HCC.

Distinguishing intrahepatic mass-forming biliary carcinomas from hepatocellular carcinoma by computed tomography and magnetic resonance imaging using the Bayesian method: a bi-center study

OBJECTIVES

To determine imaging hallmarks for distinguishing intrahepatic mass-forming biliary carcinomas (IMBCs) from hepatocellular carcinoma (HCC) and to validate their diagnostic ability using Bayesian statistics.

METHODS

Study 1 retrospectively identified clinical and imaging hallmarks that distinguish IMBCs (n = 41) from HCC (n = 247) using computed tomography (CT) and magnetic resonance imaging (MRI). Study 2 retrospectively assessed the diagnostic ability of these hallmarks to distinguish IMBCs (n = 37) from HCC (n = 111) using Bayesian statistics with images obtained from a different institution. We also assessed the diagnostic ability of the hallmarks in the patient subgroup with high diagnostic confidence (≥ 80% of post-test probability). Two radiologists independently evaluated the imaging findings in studies 1 and 2.

RESULTS

In study 1, arterial phase peritumoral parenchymal enhancement on CT/MRI, delayed enhancement on CT/MRI, diffusion-weighted imaging peripheral hyperintensity, and bile duct dilatation were hallmarks indicating IMBCs, whereas chronic liver disease, non-rim arterial phase hyperenhancement on CT/MRI, enhancing capsule on CT/MRI, and opposed-phase signal drop were hallmarks indicating HCC (p = 0.001-0.04). In study 2, Bayesian statistics-based post-test probability combining all hallmark features had a diagnostic accuracy of 89.2% (132/148) in distinguishing IMBCs from HCC for both readers. In the high diagnostic confidence subgroup (n = 120 and n = 124 for readers 1 and 2, respectively), the accuracy improved (95.0% (114/120) and 93.5% (116/124) for readers 1 and 2, respectively).

CONCLUSIONS

Combined interpretation of CT and MRI to identify hallmark features is useful in discriminating IMBCs from HCCs. High post-test probability by Bayesian statistics allows for a more reliable non-invasive diagnosis.

KEY POINTS

• Combined interpretation of CT and MRI to identify hallmark features was useful in discriminating intrahepatic mass-forming biliary carcinomas from hepatocellular carcinoma. • Bayesian method-based post-test probability combining all hallmark features determined in study 1 showed high (> 90%) sensitivity and specificity for distinguishing intrahepatic mass-forming biliary carcinomas from hepatocellular carcinoma. • If the post-test probability or the confidence was ≥ 80% when combining the imaging features of CT and MRI, the high specificity of > 95% was achieved without any loss of sensitivity to distinguish hepatocellular carcinoma from intrahepatic mass-forming biliary carcinomas.

Optimal Combination of Features on Gadoxetate Disodium-enhanced MR Imaging for Non-invasive Differential Diagnosis of Hepatocellular Carcinoma: The JAMP-HCC Study

Purpose:

To determine the optimal combination of gadoxetate disodium-enhanced magnetic resonance imaging (MRI) findings for the diagnosis of hepatocellular carcinoma (HCC) and to compare its diagnostic ability to that of dynamic computed tomography (CT) in patients with chronic liver disease.

Methods:

This multi-institutional study consisted of two parts: Study 1, a retrospective study to determine the optimal combination of gadoxetate disodium-enhanced MRI findings (decision tree and logistic model) to distinguish HCC (n = 199) from benign (n = 81) or other malignant lesions (n = 95) (375 nodules in 269 patients) and Study 2, a prospective study to compare the diagnostic ability of gadoxetate disodium-enhanced MRI to distinguish HCC (n = 73) from benign (n = 15) or other malignant lesions (n = 12) with that of dynamic CT (100 nodules in 83 patients). Two radiologists independently evaluated the imaging findings (Study 1 and 2) and made a practical diagnosis (Study 2).

Results:

In Study 1, rim or whole enhancement on arterial phase images, signal intensities on T₂-weighted/diffusion-weighted/portal venous/transitional/hepatobiliary phase images, and signal drop on opposed-phase images were independently useful for differential diagnosis. In Study 2, the accuracy, sensitivity, negative predictive value, and negative likelihood ratio of the CT decision tree (reader 2) were higher than those of MRI Model 2 (P = 0.015–0.033). There were no other significant differences in diagnostic ability (P = 0.059–1.000) and radiologist-made practical diagnosis (P = 0.059–1.000) between gadoxetate disodium-enhanced MRI and CT.

Conclusion:

We identified the optimal combination of gadoxetate disodium-enhanced MRI findings for HCC diagnosis. However, its diagnostic ability was not superior to that of dynamic CT.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

Motion Artifact Reduction Using a Convolutional Neural Network for Dynamic Contrast Enhanced MR Imaging of the Liver

Purpose:

To improve the quality of images obtained via dynamic contrast enhanced MRI (DCE-MRI), which contain motion artifacts and blurring using a deep learning approach.

Materials and Methods:

A multi-channel convolutional neural network-based method is proposed for reducing the motion artifacts and blurring caused by respiratory motion in images obtained via DCE-MRI of the liver. The training datasets for the neural network included images with and without respiration-induced motion artifacts or blurring, and the distortions were generated by simulating the phase error in k-space. Patient studies were conducted using a multi-phase T₁-weighted spoiled gradient echo sequence for the liver, which contained breath-hold failures occurring during data acquisition. The trained network was applied to the acquired images to analyze the filtering performance, and the intensities and contrast ratios before and after denoising were compared via Bland–Altman plots.

Results:

The proposed network was found to be significantly reducing the magnitude of the artifacts and blurring induced by respiratory motion, and the contrast ratios of the images after processing via the network were consistent with those of the unprocessed images.

Conclusion:

A deep learning-based method for removing motion artifacts in images obtained via DCE-MRI of the liver was demonstrated and validated.

Predicting Patients With Insufficient Liver Enhancement in the Hepatobiliary Phase Before the Injection of Gadoxetic Acid: A Practical Approach Using the Bayesian Method

BACKGROUND

Gadoxetic acid-enhanced hepatobiliary phase (HBP) is useful in liver MRI, but sometimes shows insufficient liver enhancement. There is no established method to predict insufficient liver enhancement before the contrast injection.

PURPOSE

To reveal the utility of the Bayesian method for predicting patients with insufficient liver enhancement in the gadoxetic acid-enhanced HBP.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 576 patients with chronic liver disease.

FIELD STRENGTH/SEQUENCE

3T/3D gradient-echo T₁ -weighted imaging and MR elastography (MRE).

ASSESSMENT

The patients were divided into two groups: insufficient and sufficient liver enhancement in HBP according to the liver-to-portal vein signal intensity ratio. Various parameters, including liver function tests and liver stiffness by MRE, were evaluated as predictors of insufficient liver enhancement.

STATISTICAL TESTS

We used Chi-square/Student's t-test/logistic regression analysis to determine independent associates, and Bayes' theorem to estimate the probability of insufficient (or sufficient) liver enhancement. The feasibility of Bayesian prediction of insufficient liver enhancement was tested by leave-one-out cross-validation to calculate sensitivity and specificity for single variables and combinations of some variables in all patients and in a subpopulation showing a confidence level of >80%.

RESULTS

Independent associates of insufficient liver enhancement in HBP included: serum albumin (odds ratio [OR] = 4.82, P < 0.001), total bilirubin (OR = 0.30, P < 0.00), platelet count (OR = 1.54, P < 0.00), and liver stiffness by MRE (OR = 0.59, P < 0.00). The accuracy of Bayesian prediction of insufficient liver enhancement was 80.9% (466/576) for the single parameter of albumin and 79.0% (455/576) for total bilirubin, and was increased to 85.2% (487/576) for a combination of albumin, total bilirubin, and liver stiffness. In patients who showed a confidence level of >80%, the accuracy was 89.0% (439/493) for the above combination.

DATA CONCLUSION

Bayesian prediction was useful to predict patients with insufficient enhancement by combining serum liver function tests and liver stiffness by MRE.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:62-69.

Modified CAIPIRINHA-VIBE without view-sharing on gadoxetic acid-enhanced multi-arterial phase MR imaging for diagnosing hepatocellular carcinoma: comparison with the CAIPIRINHA-Dixon-TWIST-VIBE

PURPOSE

We evaluated the detection rate and degree of motion artifact of the modified CAIPIRINHA-VIBE (mC-VIBE) without view-sharing and compare them with the CAIPIRINHA-Dixon-TWIST-VIBE (CDT-VIBE) with view-sharing on multi-arterial gadoxetic acid-enhanced liver MRI in the assessment of hepatocellular carcinoma (HCC).

MATERIAL AND METHODS

We retrospectively identified 114 pathological-proven hepatic tumors in 114 patients with risk of HCC who underwent multi-arterial gadoxetic acid-enhanced MRI between June 2016 and June 2018. All patients underwent triple arterial phase imaging using the mC-VIBE without view-sharing (54 patients; 49 HCCs and 5 non-HCCs) or the CDT-VIBE with view-sharing (60 patients; 55 HCCs and 5 non-HCCs). We compared the detection rate of two sequences for HCC, with reference to LI-RADS.V.2017. We also compared the mean motion scores and proportions of transient severe motion (TSM) in two sequences.

RESULT

For the examination using the mC-VIBE, the HCC-detection rate was significantly higher, compared with that using CDT-VIBE (93.9% [46/49] vs 80.0% [44/55], respectively; p = 0.047). For the examination with the mC-VIBE, mean motion scores were significantly lower compared with those of CDT-VIBE for all multi-arterial phases (1.21, 1.19, and 1.15 vs. 1.82, 1.85, and 1.84, respectively; p < 0.001 for all three comparisons). The proportion of TSM in the CDT-VIBE was significantly higher than that in the mC-VIBE (15.0% [9/60] vs 0.0% [0/54], respectively; p = 0.003).

CONCLUSION

In multi-arterial phase gadoxetic acid-enhanced MRI, the mC-VIBE sequence without view-sharing has slightly higher HCC-detection rate and fewer motion artifacts compared with CDT-VIBE with view-sharing.

KEY POINTS

• Multi-arterial phase using the mC-VIBE without view-sharing can overcome motion artifacts, resulting in providing optimal arterial phase imaging. • The HCC-detection rate is slightly higher with the mC-VIBE vs. CAIPIRINHA-Dixon-TWIST-VIBE with view-sharing (CDT-VIBE). • View-sharing of CDT-VIBE in the multi-arterial phase is associated with increased frequency of TSM.

Gadoxetic Acid-enhanced MRI of Hepatocellular Carcinoma: Value of Washout in Transitional and Hepatobiliary Phases

Background Current Liver Imaging Reporting and Data System guidelines define the washout appearance of gadoxetic acid-enhanced MRI only during the portal venous phase. Defining washout only during the portal venous phase may lead to lower sensitivity for diagnosis of hepatocellular carcinoma (HCC). Purpose To compare the diagnostic performances of three gadoxetic acid-enhanced MRI criteria for HCC according to the phases during which washout appearance was determined. Materials and Methods In this retrospective study, patients with a hepatic nodule detected at US surveillance for HCC from January to December 2012 underwent gadoxetic acid-enhanced MRI. Three diagnostic MRI criteria for HCC were defined according to the phases during which washout appearance was observed, with the presence of arterial phase hyperenhancement and hypointensity noted (a) only during the portal venous phase, with washout confined to the portal venous phase; (b) during the portal venous phase or transitional phase, with washout extended to the transitional phase; or (c) during the portal venous, transitional, or hepatobiliary phase, with washout extended to the hepatobiliary phase. If a nodule showed marked T2 hyperintensity or a targetoid appearance, it was precluded from the diagnosis of HCC. The sensitivity and specificity were compared by using a generalized estimating equation. Results A total of 178 patients were included (mean age ± standard deviation, 55.3 years ± 9.1) with 203 surgically confirmed hepatic nodules (186 HCCs and 17 non-HCCs) measuring 3.0 cm or smaller. The sensitivity with washout extended to the hepatobiliary phase (95.2% [177 of 186]) was better than that with washout extended to the transitional phase (90.9% [169 of 186]; P = .01) and washout confined to the portal venous phase (75.3% [140 of 186]; P < .01). The specificity with extensions of washout to the transitional phase and hepatobiliary phase (82% [14 of 17] for both) was similar to that obtained with washout confined to the portal venous phase (94.1% [16 of 17]) (P = .47). Conclusion After exclusion of typical hemangiomas and nodules with a targetoid appearance, extending washout appearance to the transitional or hepatobiliary phase (instead of restricting it to the portal venous phase) allowed higher sensitivity without a reduction in specificity. © RSNA, 2019 See also the editorial by Fowler and Sirlin in this issue.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

Four-dimensional Flow MRI as a Marker for Risk Stratification of Gastroesophageal Varices in Patients with Liver Cirrhosis

Purpose To assess the feasibility of four-dimensional (4D) flow MRI as a noninvasive imaging marker for stratifying the risk of variceal bleeding in patients with liver cirrhosis. Materials and Methods This study recruited participants scheduled for both liver MRI and gastroesophageal endoscopy. Risk of variceal bleeding was assessed at endoscopy by using a three-point scale: no varices, low risk, and high risk requiring treatment. Four-dimensional flow MRI was used to create angiograms for evaluating visibility of varices and to measure flow volumes in main portal vein (PV), superior mesenteric vein, splenic vein (SV), and azygos vein. Fractional flow changes in PV and SV were calculated to quantify shunting (outflow) from PV and SV into varices. Logistic analysis was used to identify the independent indicator of high-risk varices. Results There were 23 participants (mean age, 52.3 years; age range, 25-75 years), including 14 men (mean age, 51.7 years; age range, 25-75 years) and nine women (mean age, 53.2 years; age range, 31-72 years) with no varices (n = 8), low-risk varices (n = 8), and high-risk varices (n = 7) determined at endoscopy. Four-dimensional flow MRI-based angiography helped radiologists to view varices in four of 15 participants with varices. Independent indicators of high-risk varices were flow volume in the azygos vein greater than 0.1 L/min (P = .034; 100% sensitivity [seven of seven] and 62% specificity [10 of 16]) and fractional flow change in PV of less than 0 (P < .001; 100% sensitivity [seven of seven] and 94% specificity [15 of 16]). Conclusion Azygos flow greater than 0.1 L/min and portal venous flow less than the sum of splenic and superior mesenteric vein flow are useful markers to stratify the risk of gastroesophageal varices bleeding in patients with liver cirrhosis. © RSNA, 2018 Online supplemental material is available for this article.

Retrospective validation of a new diagnostic criterion for hepatocellular carcinoma on gadoxetic acid-enhanced MRI: can hypointensity on the hepatobiliary phase be used as an alternative to washout with the aid of ancillary features?

OBJECTIVES

To validate new diagnostic criteria for hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MR imaging (Gd-EOB-MRI) using hypointensity on the hepatobiliary phase (HBP) as an alternative to washout in combination with ancillary features.

METHODS

This retrospective study included 288 patients at high risk for HCC with 387 nodules (HCCs, n=292; non-HCCs, n=95) showing arterial phase hyper-enhancement (APHE) ≥1 cm on Gd-EOB-MRI. Imaging diagnoses of HCCs were made using different criteria: APHE plus hypointensity on the portal venous phase (PVP) (criterion 1), APHE plus hypointensity on the PVP and/or transitional phase (TP) (criterion 2), APHE plus hypointensity on the PVP and/or TP and/or HBP (criterion 3), and criterion 3 plus non-LR-1/2/M according to the Liver Imaging Reporting and Data System (LI-RADS) v2017 considering ancillary features (criterion 4). Sensitivities and specificities of those criteria were compared using McNemar's test.

RESULTS

Among diagnostic criteria for HCCs, criteria 3 and 4 showed significantly higher sensitivities (93.8% and 92.5%, respectively) than criteria 1 and 2 (70.9% and 86.6%, respectively) (p values <0.001). The specificity of criterion 4 (87.4%) was shown to be significantly higher than that of criterion 3 (48.4%, p<0.001), albeit comparable to criterion 2 (86.3%, p>0.999) and significantly lower than criterion 1 (97.9%, p=0.002).

CONCLUSIONS

In the non-invasive diagnosis of HCCs on Gd-EOB-MRI, HBP hypointensity may be used as an alternative to washout enabling a highly sensitive diagnosis with little loss in specificity if it is used after excluding nodules considered to be benignities or non-HCC malignancies based on characteristic imaging features.

KEY POINTS

• Gd-EOB-MRI enhancement and ancillary features can be used to diagnose HCC. • Exclusion of LR-1/2/M improves specificity when HBP hypointensity is used.

Performance of Gd-EOB-DTPA-enhanced MRI for the diagnosis of LI-RADS 4 category hepatocellular carcinoma nodules with different diameters

In 2011, the American College of Radiology released a standardized reporting and data collection system, named Liver Imaging Reporting and Data System (LI-RADS), to improve the consistency of diagnostic imaging examinations of hepatocellular carcinoma (HCC). When the LI-RADS guideline was updated in 2014, hepatobiliary contrast agents, including gadoxetate acid (Gd-EOB-DTPA), were incorporated into the system. However, the diagnostic performance of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) for nodules of different diameters has not been addressed. In the present study, a total of 263 LI-RADS 4 category hepatic nodules were examined blindly and independently by two radiologists. All nodules were divided into two datasets: Set 1 (n=86) that included nodules with iso/hypo-intensity in the arterial phase (HCC, n=42; non-HCC, n=44) and set 2 (n=177) that included nodules with hyper-intensity in the arterial phase (HCC, n=131; non-HCC, n=46). The diagnostic performance of Gd-EOB-DTPA-enhanced MRI for evaluation of nodules with different diameters was evaluated. The present study revealed that the diagnostic performance of Gd-EOB-enhanced MRI of larger nodules (>2 cm) was higher compared with (<2 cm) smaller nodules. The FPR of large nodules (>2 cm) with a hypervascular pattern was lower compared with smaller nodules (<2 cm) with hypovascular pattern. In conclusion, Gd-EOB-enhanced MRI is useful for the diagnosis of HCC where hypervascular LI-RADS 4 nodules are >2 cm in diameter. However, Gd-EOB-enhanced MRI may be of limited use for the assessment of nodules that <20 mm due to low diagnostic performance and high FPR.

LI-RADS and transplantation for hepatocellular carcinoma

Patients with hepatocellular carcinoma (HCC) may be eligible for liver transplantation. Liver transplant candidates with HCC compete for the same deceased donor organs as those without HCC. These scarce organs must be allocated fairly and justly to those who will benefit most. Unlike most other cancers, HCC is often diagnosed noninvasively by imaging without biopsy confirmation. Therefore, radiologists play an important role in diagnosing definite HCC (i.e., LR-5 category) that counts toward staging and determination of liver transplant eligibility. This review explains the conversion of LI-RADS observation categories to organ procurement and transplantation network classes, illustrates the radiologic T-staging systems, reviews selection criteria for liver transplant eligibility, and discusses prioritization of liver transplant candidates with HCC. In addition, this review summarizes imaging requirements, including contrast agents accepted, minimum specifications for dynamic CT or MRI of the liver, and modalities accepted for assessment of extrahepatic spread or metastatic disease in liver transplant candidates with HCC.

LI-RADS M (LR-M): definite or probable malignancy, not specific for hepatocellular carcinoma

LI-RADS v2017 introduces major changes to the diagnostic criteria for LR-M observations to better guide radiologists in the use of this malignant category designation. LR-M is intended to preserve the specificity of the LI-RADS algorithm for diagnosis of HCC while not losing sensitivity for diagnosis of malignancy. The purpose of this paper is to provide a brief background on LR-M, discuss the diagnostic criteria new to v2017, special considerations for its application, and management implications.

Imaging for the diagnosis of hepatocellular carcinoma: A systematic review and meta-analysis

Multiphasic computed tomography (CT) and magnetic resonance imaging (MRI) are both used for noninvasive diagnosis of hepatocellular carcinoma (HCC) in patients with cirrhosis. To determine if there is a relative diagnostic benefit of one over the other, we synthesized evidence regarding the relative performance of CT, extracellular contrast-enhanced MRI, and gadoxetate-enhanced MRI for diagnosis of HCC in patients with cirrhosis. We also assessed whether liver biopsy versus follow-up with the same versus alternative imaging is best for CT-indeterminate or MRI-indeterminate liver nodules in patients with cirrhosis. We searched multiple databases from inception to April 27, 2016, for studies comparing CT with extracellular contrast-enhanced MRI or gadoxetate-enhanced MRI in adults with cirrhosis and suspected HCC. Two reviewers independently selected studies and extracted data. Of 33 included studies, 19 were comprehensive, while 14 reported sensitivity only. For all tumor sizes, the 19 comprehensive comparisons showed significantly higher sensitivity (0.82 versus 0.66) and lower negative likelihood ratio (0.20 versus 0.37) for MRI over CT. The specificities of MRI versus CT (0.91 versus 0.92) and the positive likelihood ratios (8.8 versus 8.1) were not different. All three modalities performed better for HCCs ≥2 cm. Performance was poor for HCCs <1 cm. No studies examined whether adults with cirrhosis and an indeterminate nodule are best evaluated using biopsy, repeated imaging, or alternative imaging. Concerns about publication bias, inconsistent study results, increased risk of bias, and clinical factors precluded support for exclusive use of either gadoxetate-enhanced or extracellular contrast-enhanced MRI over CT.

CONCLUSION

CT, extracellular contrast-enhanced MRI, or gadoxetate-enhanced MRI could not be definitively preferred for HCC diagnosis in patients with cirrhosis; in patients with cirrhosis and an indeterminate mass, there were insufficient data comparing biopsy to repeat cross-sectional imaging or alternative imaging. (Hepatology 2018;67:401-421).

Diagnostic accuracy of prospective application of the Liver Imaging Reporting and Data System (LI-RADS) in gadoxetate-enhanced MRI

OBJECTIVES

To evaluate the diagnostic performance of the LI-RADS (v2014) on gadoxetate-enhanced MRI prospectively applied in actual practice.

METHODS

We retrospectively reviewed the prospectively written radiology reports of 143 treatment-naïve at-risk patients who underwent gadoxetate-enhanced liver MRI from January to December 2014, and identified 202 hepatic observations categorized using the LI-RADS. The diagnostic performances of LI-RADS categories for hepatocellular carcinoma (HCC) and hepatic malignancy were calculated.

RESULTS

Twenty (69.0 %) of 29 LR-4, 73 (97.3 %) of 75 LR-5, and all of five (100 %) LR-5V observations were HCCs. The remaining two (2.7 %) LR-5 observations were combined hepatocellular-cholangiocarcinomas, while 10 (76.9 %) of 13 LR-M observations were HCCs. The sensitivity and specificity of LR-5/5V for HCC were 60.5 % and 97.3 %, respectively. Including LR-M in the diagnostic criteria for HCC increased sensitivity (68.2 %, p = 0.002) but decreased specificity without statistical significance (93.2 %, p = 0.154). LR-5/5V/M yielded sensitivity of 68.9 % and specificity of 100.0 % for hepatic malignancy.

CONCLUSIONS

LI-RADS v2014 was successfully applied on gadoxetate-enhanced MRI in clinical practice. LR-5/5V was the most specific diagnostic measure for HCC, but most LR-M observations were HCCs and a considerable portion of non-HCC malignancies were categorized as LR-4 or LR-5.

KEY POINTS

• LR-5/5V provided a highly specific diagnosis for HCC. • Half of non-HCC malignancies were categorized as LR-4 or LR-5. • The majority of LR-M observations were finally diagnosed as HCCs. • More sensitive diagnosis of HCC was feasible with LR-5/5V/M on gadoxetate-enhanced MRI. • Observations in either LR-5/5V or LR-M categories were definitely malignant.

Gadoxetic acid disodium-enhanced magnetic resonance imaging outperformed multidetector computed tomography in diagnosing small hepatocellular carcinoma: A meta-analysis

Early detection of small hepatocellular carcinoma (HCC) lesions can improve longterm patient survival. A systematic review and meta-analysis of the diagnostic performance of gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and multidetector computed tomography (MDCT) was performed in diagnosing small HCCs measuring up to 2 cm (≤2 cm). Two investigators searched multiple databases for studies in which the performances of either Gd-EOB-DTPA-enhanced MRI or MDCT were reported with sufficient data to construct 2 × 2 contingency tables for diagnosing HCCs up to 2 cm on a per-lesion or per-patient level. Diagnostic performances were quantitatively pooled by a bivariate random-effect model with further meta-regression and subgroup analyses. A total of 27 studies (14 on Gd-EOB-DTPA-enhanced MRI, 9 on MDCT, and 4 on both) were included, enrolling a total of 1735 patients on Gd-EOB-DTPA-enhanced MRI and 1781 patients on MDCT. Gd-EOB-DTPA-enhanced MRI demonstrated significantly higher overall sensitivity than did MDCT (0.96 versus 0.65; P < 0.01), without substantial loss of specificity (0.94 versus 0.98; P > 0.05). Area under the summary receiver operating characteristic curve was 0.97 with Gd-EOB-DTPA-enhanced MRI and 0.85 with MDCT. Regarding Gd-EOB-DTPA-enhanced MRI, sensitivity was significantly higher for studies from non-Asian countries than Asian countries (0.96 versus 0.93; P < 0.01), for retrospective studies than prospective studies (0.95 versus 0.91; P < 0.01), and for those with Gd-EOB-DTPA injection rate ≥ 1.5 mL/s than that of <1.5 mL/s (0.97 versus 0.90; P < 0.01). In conclusion, Gd-EOB-DTPA-enhanced MRI demonstrated higher sensitivity and overall diagnostic accuracy than MDCT, and thus should be the preferred imaging modality for diagnosing small HCCs measuring up to 2 cm. Liver Transplantation 23 1505-1518 2017 AASLD.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging

PURPOSE OF REVIEW

This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses.

RECENT FINDINGS

The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Differentiation of Hepatocellular Carcinoma from Other Hepatic Malignancies in Patients at Risk: Diagnostic Performance of the Liver Imaging Reporting and Data System Version 2014

Purpose To evaluate the diagnostic performance and interrater reliability of the Liver Imaging Reporting and Data System (LI-RADS) version 2014 in differentiating hepatocellular carcinoma (HCC) from non-HCC malignancy in a population of patients at risk for HCC. Materials and Methods This retrospective HIPAA-compliant institutional review board-approved study was exempt from informed consent. A total of 178 pathology-proven malignant liver masses were identified in 178 patients at risk for HCC but without established extrahepatic malignancy from August 2012 through August 2015. Two readers blinded to pathology findings and clinical follow-up data independently evaluated a liver protocol magnetic resonance or computed tomography study for each lesion and assigned LI-RADS categories, scoring all major and most ancillary features. Statistical analyses included the independent samples t test, x² test, Fisher exact test, and Cohen k. Results This study included 136 HCCs and 42 non-HCC malignancies. Specificity and positive predictive value of an HCC imaging diagnosis (LR-5 or LR-5V) were 69.0% and 90.5%, respectively, for reader 1 (R1) and 88.3% and 95.5%, respectively, for reader 2 (R2). Tumor in vein was a common finding in patients with non-HCC malignancies (R1, 10 of 42 [23.8%]; R2, five of 42 [11.9%]). Exclusion of the LR-5V pathway improved specificity and positive predictive value for HCC to 83.3% and 92.9%, respectively, for R1 (six fewer false-positive findings) and 92.3% and 96.4%, respectively, for R2 (one fewer false-positive finding). Among masses with arterial phase hyperenhancement, the rim pattern was more common among non-HCC malignancies than among HCCs for both readers (R1: 24 of 36 [66.7%] vs 13 of 124, [10.5%], P < .001; R2: 27 of 35 [77.1%] vs 21 of 123 [17.1%], P < .001) (k = 0.76). Exclusion of rim arterial phase hyperenhancement as a means of satisfying LR-5 criteria also improved specificity and positive predictive value for HCC (R1, two fewer false-positive findings). Conclusion Modification of the algorithmic role of tumor in vein and rim arterial phase hyperenhancement improves the diagnostic performance of LI-RADS version 2014 in differentiating HCC from non-HCC malignancy. ^© RSNA, 2017 Online supplemental material is available for this article.

Diagnostic accuracy of gadoxetic acid-enhanced MR for small hypervascular hepatocellular carcinoma and the concordance rate of Liver Imaging Reporting and Data System (LI-RADS)

Background & aims

To assess diagnostic accuracy of gadoxetic acid–enhanced MR for small hypervascular hepatocellular carcinoma (HCC) detected by C-arm CT and concordance rate of Liver Imaging Reporting and Data System (LI-RADS).

Methods

In this retrospective study, we recruited 4,544 patients suspected of having HCC underwent C-arm CT from November 2008 to May 2013. Among these patients, gadoxetic acid–enhanced MR was performed in 167 patients with HCC (n = 379; 257 > 1 cm, 122 ≤ 1 cm). HCC was confirmed by MR, CT, or follow-up images. Two radiologists graded likelihood of HCC and assessed MR features. Jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was performed. All HCCs were evaluated concordance rate of LI-RADS.

Results

Mean JAFROC figure of merit for large (>1-cm) HCC was 0.948, while that for small HCC was 0.787 with fair agreement (κ = 0.409). Mean sensitivity and positive predictive value (PPV) were 91% and 90% for large HCC versus 63.0% and 79% for small HCC, respectively. Seventeen of 122 small HCCs (13.9%) were not visible on MR. Among 379 HCCs, 99 met LR-5, and 259 met LR-4. Common features for small HCC included arterial enhancement (81.9%), hepatobiliary phase hypointensity (80.3%), and delayed washout (72.9%).

Conclusion

Diagnostic accuracy of gadoxetic acid–enhanced MR imaging for small, hypervascular HCCs (Mean figure of merit = 0.787) was still low compared with large HCC (Mean figure of merit = 0.948). LR-5 and LR-4 covered 94% (358/379) of the HCCs.

Diagnosis of hepatocellular carcinoma: An update on international guidelines

Imaging is essential for the successful management of patients with or at risk of developing hepatocellular carcinoma (HCC). If ultrasound remains the key screening modality, computed tomography and magnetic resonance imaging (MRI) can play a major role in the characterization and noninvasive diagnosis of nodules in patients at risk of developing HCC. Each technique has succeeded in adapting to the wide histological spectrum of focal liver lesions. In this review, we discuss recent advancements in imaging techniques and evaluation - notably diffusion-weighted imaging, contrast-enhanced ultrasound, and liver-specific MRI contrast agents - as well as their addition to international guidelines and reporting systems such as the Liver imaging reporting and data system (LI-RADS).

Magnetic resonance imaging of the cirrhotic liver: diagnosis of hepatocellular carcinoma and evaluation of response to treatment - Part 2

In the second part of this review, we will describe the ancillary imaging features of hepatocellular carcinoma (HCC) that can be seen on standard magnetic resonance imaging (MRI) protocol, and on novel and emerging protocols such as diffusion weighted imaging and utilization of hepatocyte-specific/hepatobiliary contrast agent. We will also describe the morphologic sub-types of HCC, and give a simplified non-invasive diagnostic algorithm for HCC, followed by a brief description of the liver imaging reporting and data system (LI-RADS), and MRI assessment of tumor response following locoregional therapy.

Diagnostic Accuracy of Gd-EOB-DTPA for Detection Hepatocellular Carcinoma (HCC): A Comparative Study with Dynamic Contrast Enhanced Magnetic Resonance Imaging (MRI) and Dynamic Contrast Enhanced Computed Tomography (CT)

Background

To compare the diagnostic accuracy of hepato-biliary (HB) phase with gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) with dynamic contrast-enhanced MR imaging (DCEMRI) and contrast-enhanced CT (DCECT) for hepatocellular carcinoma (HCC) detection.

Material/Methods

73 patients underwent DCECT and Gd-EOB-DTPA-3T-MR. Lesions were classified using a five-point confidence scale. Reference standard was a combination of pathological evidence and tumor growth at follow-up CT/MR at 12 months. Receiver Operating Characteristic (ROC) curves were obtained.

Results

A total of 125 lesions were confirmed in 73 patients. As many as 74 were HCCs and 51 were benign. Area under the curve (AUC) was 0.984 for DCEMRI+HB phase vs. 0.934 for DCEMRI (p<0.68) and 0.852 for DCECT (p<0.001). For lesions >20 mm (n.40), AUC was 0.984 for DCEMRI+HB phase, 0.999 for DCEMRI, and 0.913 for DCECT, (p=n.s.). For lesions <20 mm (n.85) AUC was 0.982 for DCEMRI+HB phase vs. 0.910 for DCEMRI (p<0.01) and 0.828 for DCECT (p<0.001).

Conclusions

The addition of HB phase to DCEMRI provides an incremental accuracy of 4.5% compared to DCEMRI and DCECT for HCC detection. The accuracy of Gd-EOB-DTPA-3T-MR significantly improves for lesions <20 mm. No significant improvement is observed for lesions >20 mm and patients with Child-Pugh class B or C.