MR-imaging features of hepatocellular carcinoma capsule appearance in cirrhotic liver: comparison of gadoxetic acid and gadobenate dimeglumine

Intraindividual crossover comparison of gadobenate dimeglumine-enhanced and gadoxetate disodium-enhanced MRI for characterizing focal liver lesions

BACKGROUND

Gadobenate and gadoxetate are hepatobiliary magnetic resonance imaging (MRI) contrast agents. We intraindividually compared these two agents for the characterization of focal liver lesions (FLLs).

METHODS

A total of 140 adult subjects were randomized to undergo two 3-T MRI exams separated by 7-14 days, one with 0.05 mmol/kg gadobenate and one with 0.025 mmol/kg gadoxetate. For both exams, we acquired the same unenhanced T1-weighted, T2-weighted, and diffusion-weighted sequences, followed by contrast-enhanced T1-weighted sequences during the dynamic and hepatobiliary phases (HBP) (at 20 min for gadoxetate, at 120 min for gadobenate). Three experienced unaffiliated readers independently evaluated each exam in blinded, randomized order for lesion nature (benign/malignant) and specific lesion diagnosis. McNemar test, Wald tests. paired t-tests and κ statistics were used.

RESULTS

A total of 208 FLLs (108 malignant and 100 benign) were confirmed at final diagnosis. Sensitivity and specificity for malignant/benign differentiation ranged from 91.6% to 99.1% and from 87.5% to 90.5% for gadobenate, and from 86.0% to 91.6% and from 79.7% to 83.6% for gadoxetate. Significantly (p ≤ 0.025) higher values for gadobenate were determined for all diagnostic performance parameters except for sensitivity and negative predictive value for one reader. Significantly (p < 0.001) greater accuracy and confidence for specific lesion diagnosis was achieved with gadobenate for two of three blinded readers. Interreader agreement for malignant/benign differentiation was better with gadobenate (κ = 0.91 versus κ = 0.72).

CONCLUSION

Gadobenate was superior to gadoxetate for the differentiation and diagnosis of malignant and benign FLLs for two of three readers. Further confirmatory studies that include a wider representation of different types of FLLs are warranted.

RELEVANCE STATEMENT

Better diagnostic performance and greater confidence in the characterization of FLLs with gadobenate might improve patient management decisions and timings, and potentially lead to better patient outcomes.

KEY POINTS

Better diagnostic performance for the differentiation of FLLs was achieved with gadobenate for two of three readers. Reader confidence for lesion diagnosis was greater with gadobenate. Superior dynamic phase imaging with gadobenate was crucial for accurate lesion diagnosis.

LI-RADS v2018 category and imaging features: inter-modality agreement between contrast-enhanced CT, gadoxetate disodium-enhanced MRI, and extracellular contrast-enhanced MRI

PURPOSE

To perform an intra-individual comparison of LI-RADS category and imaging features in patients at high risk of hepatocellular carcinoma (HCC) on contrast-enhanced CT, gadoxetate disodium-enhanced MRI (EOB-MRI), and extracellular agent-enhanced MRI (ECA-MRI) and to analyze the diagnostic performance of each imaging modality.

METHOD

This retrospective study included cirrhotic patients with at least one LR-3, LR-4, LR-5, LR-M or LR-TIV observation imaged with at least two imaging modalities among CT, EOB-MRI, or ECA-MRI. Two radiologists evaluated the observations using the LI-RADS v2018 diagnostic algorithm. Reference standard included pathologic confirmation and imaging criteria according to LI-RADS v2018. Imaging features were compared between different exams using the McNemar test. Inter-modality agreement was calculated by using the weighted Cohen's kappa (k) test.

RESULTS

A total of 144 observations (mean size 34.0 ± 32.4 mm) in 96 patients were included. There were no significant differences in the detection of major and ancillary imaging features between the three imaging modalities. When considering all the observations, inter-modality agreement for category assignment was substantial between CT and EOB-MRI (k 0.60; 95%CI 0.44, 0.75), moderate between CT and ECA-MRI (k 0.46; 95%CI 0.22, 0.69) and substantial between EOB-MRI and ECA-MRI (k 0.72; 95%CI 0.59, 0.85). In observations smaller than 20 mm, inter-modality agreement was fair between CT and EOB-MRI (k 0.26; 95%CI 0.05, 0.47), moderate between CT and ECA-MRI (k 0.42; 95%CI -0.02, 0.88), and substantial between EOB-MRI and ECA-MRI (k 0.65; 95%CI 0.47, 0.82). ECA-MRI demonstrated the highest sensitivity (70%) and specificity (100%) when considering LR-5 as predictor of HCC.

CONCLUSIONS

Inter-modality agreement between CT, ECA-MRI, and EOB-MRI decreases in observations smaller than 20 mm. ECA-MRI has the provided higher sensitivity for the diagnosis of HCC.

Re-assessing the diagnostic value of the enhancing capsule in hepatocellular carcinoma imaging

BACKGROUNDS/AIMS

The enhancing capsule (EC) in hepatocellular carcinoma (HCC) diagnosis has received varying degrees of recognition across major guidelines. This study aimed to assess the diagnostic utility of EC in HCC detection.

METHODS

We retrospectively analyzed patients who underwent pre-surgical computed tomography (CT) and hepatobiliary agent-enhanced magnetic resonance imaging (HBA-MRI) between January 2016 and December 2019. A single hepatic tumor was confirmed based on the pathology of each patient. Three radiologists independently reviewed the images according to the Liver Imaging Reporting and Data System (LI-RADS) v2018 criteria and reached a consensus. Interobserver agreement for EC before reaching a consensus was quantified using Fleiss κ statistics. The impact of EC on the LI-RADS classification was assessed by comparing the positive predictive values for HCC detection in the presence and absence of EC.

RESULTS

In total, 237 patients (median age, 60 years; 184 men) with 237 observations were included. The interobserver agreement for EC detection was notably low for CT (κ=0.169) and HBA-MRI (κ=0.138). The presence of EC did not significantly alter the positive predictive value for HCC detection in LI-RADS category 5 observations on CT (94.1% [80/85] vs. 94.6% [88/93], P=0.886) or HBAMRI (95.7% [88/92] vs. 90.6% [77/85], P=0.178).

CONCLUSIONS

The diagnostic value of EC in HCC diagnosis remains questionable, given its poor interobserver agreement and negligible impact on positive predictive values for HCC detection. This study challenges the emphasis on EC in certain diagnostic guidelines and suggests the need to re-evaluate its role in HCC imaging.

Comparative analysis of the performance of hepatobiliary agents in depicting MRI features of microvascular infiltration in hepatocellular carcinoma

OBJECTIVE

To compare the ability to depict MRI features of hepatobiliary agents in microvascular infiltration (MVI) of hepatocellular carcinoma (HCC) during different stages of dynamic enhancement MRI.

MATERIALS AND METHODS

A retrospective study included 111 HCC lesions scanned with either Gd-EOB-DTPA or Gd-BOPTA. All cases underwent multiphase dynamic contrast-enhanced scanning before surgery, including arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). Two abdominal radiologists independently evaluated MRI features of MVI in HCC, such as peritumoral hyperenhancement, incomplete capsule, non-smooth tumor margins, and peritumoral hypointensity. Finally, the results were reviewed by the third senior abdominal radiologist. Chi-square (χ2) Inspection for comparison between groups. P < 0.05 is considered statistically significant. Receiver operating characteristic (ROC) curve was used to evaluate correlation with pathology, and the area under the curve (AUC) and 95% confidence interval (95% CI) were calculated.

RESULTS

Among the four MVI evaluation signs, Gd-BOPTA showed significant differences in displaying two signs in the HBP (P < 0.05:0.000, 0.000), while Gd-EOB-DTPA exhibited significant differences in displaying all four signs (P < 0.05:0.005, 0.006, 0.000, 0.002). The results of the evaluations of the two contrast agents in the DP phase with incomplete capsulation showed the highest correlation with pathology (AUC: 0.843, 0.761). By combining the four MRI features, Gd-BOPTA and Gd-EOB-DTPA have correlated significantly with pathology, and Gd-BOPTA is better (AUC: 0.9312vs0.8712).

CONCLUSION

The four features of hepatobiliary agent dynamic enhancement MRI demonstrate a good correlation with histopathological findings in the evaluation of MVI in HCC, and have certain clinical significance.

ESR Essentials: diagnosis of hepatocellular carcinoma-practice recommendations by ESGAR

Hepatocellular carcinoma (HCC) is the most common primary hepatic malignancy and a leading cause of cancer related death worldwide. Current guidelines for the noninvasive diagnosis of HCC are provided by the European Association for the Study of the Liver (EASL), the American Association for the Study of Liver Diseases (AASLD) which endorsed the Liver Imaging Reporting and Data System (LI-RADS) algorithm, the Korean Liver Cancer Association-National Cancer Center (KLCA-NCC), and the Asian-Pacific Association for the Study of the Liver (APASL). These allow the diagnosis of HCC in high-risk patients in the presence of typical imaging features on contrast-enhanced CT, MRI, or contrast-enhanced ultrasound. Size, non-rim arterial phase hyperenhancement, non-peripheral washout, enhancing capsule, and growth are major imaging features and they should be combined for the diagnosis of HCC. This article provides concise and relevant practice recommendations aimed at general radiologist audience, summarizing the best practice and informing on the essential imaging criteria for the diagnosis of HCC, while also discussing the high-risk population criteria, imaging modalities, and imaging features according to the current guidelines. KEY POINTS: • Noninvasive diagnosis of hepatocellular carcinoma (HCC) can be provided only in patients at high risk. • Contrast-enhanced CT or MRI are the first-line imaging exams for the diagnosis of HCC. • Major imaging features should be combined to provide the diagnosis of definitive HCC.

Comparison of the Ability of Gadobenate Dimeglumine and Gadolinium Ethoxybenzyl Dimeglumine to Display the major Features for Noninvasively Diagnosing Hepatocellular Carcinoma According to the LI-RADS 2018v

OBJECTIVE

To compare the ability of gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA) and gadobenate dimeglumine (Gd-BOPTA) to display the 3 major features recommended by the Liver Imaging Reporting and Data System (LI-RADS 2018v) for diagnosing hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

In this retrospective study, we included 98 HCC lesions that were scanned with either Gd-EOB-DTPA-MR or Gd-BOPTA-M.For each lesion, we collected multiple variables, including size and enhancement pattern in the arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). The lesion-to-liver contrast (LLC) was measured and calculated for each phase and then compared between the 2 contrast agents. A P value < .05 was considered statistically significant. The display efficiency of the LLC between Gd-BOPTA and Gd-EOB-DTPA for HCC features was evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

Between Gd-BOPTA and Gd-EOB-DTPA, significant differences were observed regarding the display efficiency for capsule enhancement and the LLC in the AP/PVP/DP (P < .05), but there was no significant difference regarding the LLC in the TP/HBP. Both Gd-BOPTA and Gd-EOB-DTPA had good display efficiency in each phase (AUCmin > 0.750). When conducting a total evaluation of the combined data across the 5 phases, the display efficiency was excellent (AUC > 0.950).

CONCLUSION

Gd-BOPTA and Gd-EOB-DTPA are liver-specific contrast agents widely used in clinical practice. They have their own characteristics in displaying the 3 main signs of HCC. For accurate noninvasive diagnosis, the choice of agent should be made according to the specific situation.

Improved diagnosis of histological capsule in hepatocallular carcinoma by using nonenhancing capsule appearance in addition to enhancing capsule appearance in gadoxetic acid-enhanced MRI

To assess the value of nonenhancing capsule by adding to enhancing capsule in gadoxetic acid-enhanced MRI (EOB-MRI) in comparison with contrast-enhanced CT (CE-CT) for diagnosing histological capsule in hepatocellular carcinoma (HCC). One-hundred fifty-one patients with HCC who underwent both CE-CT and EOB-MRI were retrospectively reviewed. Liver Imaging-Reporting and Data System (LI-RADS) v2018 imaging features, including enhancing and nonenhancing capsule were evaluated by two readers in CE-CT and EOB-MRI. Frequencies of each imaging feature were compared between CE-CT and EOB-MRI. The area under the receiver operating characteristic (AUC) curve for the diagnosis of histological capsule was compared across the following three imaging criteria: (1) enhancing capsule in CE-CT, (2) enhancing capsule in EOB-MRI, and (3) enhancing/nonenhancing capsule in EOB-MRI. Enhancing capsule in EOB-MRI was significantly less frequently depicted than that in CE-CT (p < 0.001 and = 0.016 for reader 1 and 2). Enhancing/nonenhancing capsule in EOB-MRI achieved a similar frequency of enhancing in CE-CT (p = 0.590 and 0.465 for reader 1 and 2). Adding nonenhancing capsule to enhancing capsule in EOB-MRI significantly increased AUCs (p < 0.001 for both readers) and achieved similar AUCs compared with enhancing capsule in CE-CT (p = 0.470 and 0.666 for reader 1 and 2). Adding nonenhancing capsule to the definition of capsule appearance can improve the diagnosis of capsule in EOB-MRI for the diagnosis of histological capsule in HCC and decrease discordance of capsule appearance between EOB-MRI and CE-CT.

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.

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.

Imaging Features at the Periphery: Hemodynamics, Pathophysiology, and Effect on LI-RADS Categorization

Liver lesions have different enhancement patterns at dynamic contrast-enhanced imaging. The Liver Imaging Reporting and Data System (LI-RADS) applies the enhancement kinetic of liver observations in its algorithms for imaging-based diagnosis of hepatocellular carcinoma (HCC) in at-risk populations. Therefore, careful analysis of the spatial and temporal features of these enhancement patterns is necessary to increase the accuracy of liver mass characterization. The authors focus on enhancement patterns that are found at or around the margins of liver observations-many of which are recognized and defined by LI-RADS, such as targetoid appearance, rim arterial phase hyperenhancement, peripheral washout, peripheral discontinuous nodular enhancement, enhancing capsule appearance, nonenhancing capsule appearance, corona enhancement, and periobservational arterioportal shunts-as well as peripheral and periobservational enhancement in the setting of posttreatment changes. Many of these are considered major or ancillary features of HCC, ancillary features of malignancy in general, features of non-HCC malignancy, features associated with benign entities, or features related to treatment response. Distinction between these different patterns of enhancement can help with achieving a more specific diagnosis of HCC and better assessment of response to local-regional therapy. ^©RSNA, 2021.

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.

Imaging features of gadoxetic acid-enhanced MR imaging for evaluation of tumor-infiltrating CD8 cells and PD-L1 expression in hepatocellular carcinoma

BACKGROUND

Tumor-infiltrating CD8 cells and expression of programmed cell death ligand 1 (PD-L1) are immune checkpoint markers in patients with hepatocellular carcinoma (HCC). We aimed to determine the ability of preoperative gadoxetic acid-enhanced magnetic resonance imaging (MRI) findings to predict CD8 cell density and PD-L1 expression in HCC.

METHODS

A total of 120 patients with HCC who underwent 3.0-T gadoxetic acid-enhanced MRI before curative resection from January 2016 to June 2020 were enrolled and divided into a training set (n = 84) and a testing set (n = 36). Thirty-four patients with advanced stage HCC who received anti-PD-1 inhibitor between January 2017 and April 2020 and underwent pretreated gadoxetic acid-enhanced MRI scans were enrolled in an independent validation set. PD-L1 expression and CD8 cell infiltration were assessed with immunohistochemical staining, respectively. Two radiologists blinded to pathology results evaluated the pretreated MR features in consensus. Logistic regression and the receiver operating characteristic curve (ROC) analyses were used to determine the value of image features to predict high CD8 cell density, PD-L1 positivity and the combination of high CD8 cell density and PD-L1 positivity in HCC in the training set and validated the findings in the testing set. The associations of MRI predictors with the objective response to immunotherapy were assessed in the independent validation.

RESULTS

In the training set, the independent MRI predictors were irregular tumor margin (ITM, P = 0.008) and peritumoral low signal intensity (PLSI) on hepatobiliary phase (HBP) images (P < 0.001) for PD-L1 positivity, absence of an enhancing capsule (AEC, P = 0.001) and PLSI on HBP images (P = 0.025) for high CD8 cell density, and PLSI on HBP images (P = 0.001) and ITM (P = 0.023) for the both. The area under the curves (AUCs) of the predictive models for evaluating PD-L1 positivity, high CD8 cell density and the combination of high CD8 cell density and PD-L1 positivity were 0.810 and 0.809, 0.740 and 0.728, and 0.809 and 0.874 in the training and testing set, respectively. The objective response was demonstrated to be associated with the combination of PLSI on HBP images and ITM (PHI, P = 0.004), and the combination of PLSI on HBP images and AEC (PHA, P = 0.012) in the independent validation set.

CONCLUSIONS

Pretreated MRI features have the potential to identify patients with HCC in an immune-activated state and predict outcomes of immunotherapy. Trial registration The study was retrospectively registered on March 5, 2020 with registration no. [2020] 02-012-01.

Combined computed tomography and magnetic resonance imaging improves diagnosis of hepatocellular carcinoma ≤ 3.0 cm

BACKGROUND/PURPOSE

Imaging diagnosis of hepatocellular carcinoma (HCC) is important, but the diagnostic performance of combined computed tomography (CT) and magnetic resonance imaging (MRI) using the Liver Imaging Reporting and Data System (LI-RADS) v2018 is not fully understood. We evaluated the clinical usefulness of combined CT and MRI for diagnosing HCC ≤ 3.0 cm using LI-RADS.

METHODS

In 222 patients at risk of HCC who underwent both contrast-enhanced dynamic CT and gadoxetate disodium-enhanced MRI in 2017, 291 hepatic nodules ≤ 3.0 cm were retrospectively analyzed. Two radiologists performed image analysis and assigned a LI-RADS category to each nodule. The diagnostic performance for HCC was evaluated for CT, ordinary-MRI (washout confined to portal venous-phase), and modified-MRI (washout extended to hepatobiliary phase), and sensitivity and specificity were calculated for each modality. Generalized estimating equations were used to compare the diagnostic performance for HCC between combined CT and ordinary-MRI, combined CT and modified-MRI, and CT or MRI alone. p < 0.0062 (0.05/8) was considered statistically significant following Bonferroni correction for multiple comparisons.

RESULTS

In 291 nodules, the sensitivity and specificity of CT, ordinary-MRI, and modified-MRI were 70.2% and 92.8%, 72.6% and 96.4%, and 84.6% and 88.0%, respectively. Compared with CT or MRI alone, both combined CT and ordinary-MRI (sensitivity, 83.7%; specificity, 95.2%) and combined CT and modified-MRI (sensitivity, 88.9%; specificity, 89.2%) showed significantly higher sensitivity (p ≤ 0.006), without a significant decrease in specificity (p ≥ 0.314).

CONCLUSIONS

Compared with CT or MRI alone, combined CT and MRI can increase sensitivity for diagnosing HCC ≤ 3.0 cm, without a significant decrease in specificity.

The role of lesion hypointensity on gadobenate dimeglumine-enhanced hepatobiliary phase MRI as an additional major imaging feature for HCC classification using LI-RADS v2018 criteria

OBJECTIVES

To determine the value of lesion hypointensity in the hepatobiliary phase (HBP) on gadobenate dimeglumine-enhanced MRI as an additional major imaging feature for diagnosis of hepatocellular carcinoma (HCC) using LI-RADS v2018 criteria.

METHODS

Between March 2016 and August 2018, 235 patients with 250 hepatic nodules at high risk of HCC underwent gadobenate dimeglumine-enhanced MRI. Two radiologists independently evaluated the imaging features and classified the nodules based on LI-RADS v2018 criteria, and their consensus data were used to calculate the diagnostic performance of LI-RADS categories. Two modified LI-RADS definitions were as follows: (1) LI-RADS-m1: HBP hypointensity as an additional major feature; (2) LI-RADS-m2: HBP hypointensity as an alternative to "enhancing capsule" as an additional major feature. The diagnostic performance of LR-5 categories was compared using McNemar's test.

RESULTS

The sensitivity and specificity for LR-5 classification using original LI-RADS v2018 criteria were 78.1% and 96.3%, respectively. Significantly improved sensitivity (82.7%; p = 0.004) with unchanged specificity (96.3%; p = 1.00) was seen for LR-5 classification using LI-RADS-m1. Similar sensitivity and specificity (82.7% and 96.3%, respectively) were also seen using LI-RADS-m2. Significantly improved sensitivity (79.5% vs. 64.0%; p = 0.031) with unchanged specificity (96.2% vs. 96.2%, p = 1.00) was seen using both LI-RADS-m1 and LI-RADS-m2 compared to the original LI-RADS v2018 for 39 HCC nodules measuring 10-19 mm.

CONCLUSIONS

Lesion hypointensity on gadobenate dimeglumine-enhanced HBP MRI may improve sensitivity for LR-5 classification beyond that achievable using conventional LI-RADS v2018 criteria. Lesion hypointensity may prove a suitable alternative imaging feature to enhancing capsule for accurate LR-5 classification.

KEY POINTS

• Including lesion hypointensity in the HBP as an additional major feature improved sensitivity for LR-5 classification on gadobenate dimeglumine-enhanced MRI. • Lesion hypointensity in the HBP can replace "enhancing capsule" as an additional major feature for LR-5 classification without impairing specificity.

Hepatobiliary phase hypointensity on gadobenate dimeglumine-enhanced magnetic resonance imaging may improve the diagnosis of hepatocellular carcinoma

Background

To determine the clinical value of hepatobiliary phase (HBP) hypointensity for noninvasive diagnosis of hepatocellular carcinoma (HCC).

Methods

A total of 246 high-risk patients with 263 selected nodules (126 HCCs, 137 non-HCCs) undergoing gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) were included in the study. Imaging-based diagnoses of small (≤3 cm) and large (>3 cm) HCCs were made using the following 4 criteria: (I) non-rim arterial phase hyper-enhancement (APHE) plus hypointensity on the portal venous phase (PVP); (II) non-rim APHE plus hypointensity on the PVP and/or transitional phase (TP); (III) non-rim APHE plus hypointensity on the PVP and/or TP and/or HBP; (IV) criterion 3 plus non-LR-1/2/M. Based on typical imaging features, LR-1, LR-2, or LR-M (if definitely benign, probably benign, malignant but not HCC specific, respectively) were defined according to the Liver Imaging Reporting and Data System (LI-RADS). Sensitivities and specificities of imaging criteria were calculated and compared using McNemar’s test.

Results

Among the diagnostic criteria for small HCCs, criterion 3 and 4, which included HBP hypointensity, showed significantly higher sensitivities (96.4% and 94.6%, respectively) than criterion 1 (58.9%, P<0.001 for both). Moreover, criterion 4, which included HBP hypointensity and ancillary features, showed significantly higher specificity (94.7%) than criterion 3 (66.7%, P<0.001) and comparable specificity to criterion 1 (97.4%, P=0.375), achieving the highest accuracies (94.7%). The diagnostic performance of criterion 4 for large HCCs was similar to that for small HCCs.

Conclusions

HBP hypointensity acquired from Gd-BOPTA-MRI can improve sensitivity and maintain high specificity in the diagnosis of both small and large HCCs after excluding benignities or non-HCC malignancies according to characteristic imaging features.

LI-RADS and transplantation: challenges and controversies

Patients with early stage hepatocellular carcinoma (HCC) can be cured by liver transplantation. HCC imaging features on CT or MRI are specific enough to allow for definitive diagnosis and treatment without the need of confirmatory biopsy. When applied to the appropriate at-risk population the Liver Imaging Reporting and Data System (LI-RADS) imaging criteria achieve high specificity and positive predictive value for the diagnosis of HCC. The Organ Procurement and Transplantation Network (OPTN) is the United States organization that aims to assure the adequate and fair distribution of livers across candidates. Given the importance of fair organ allocation, OPTN also provides stringent imaging criteria for the diagnosis of HCC aiming to avoid false positive diagnosis. Although most imaging criteria are identical for both systems, discrepancies between LI-RADS and the current OPTN classification system for HCC diagnosis exists. Main differences include, but are not limited to, the binary approach of OPTN to classify lesions as HCC or not, versus the probabilistic algorithmic approach of LI-RADS, technical and interpretation considerations, and the approach towards treated lesions. The purpose of this article is to highlight the similarities and discrepancies between LI-RADS and the current OPTN criteria for HCC diagnosis and the implications that these differences may have on the management of patients who are transplant candidates.

Intra-individual comparison of dual portal venous phases for non-invasive diagnosis of hepatocellular carcinoma at gadoxetic acid-enhanced liver MRI

OBJECTIVES

To compare the diagnostic performances of first and second portal venous phases (PVP1 and PVP2) in revealing washout and capsule appearance for non-invasive HCC diagnoses in gadoxetic acid-enhanced MRI (Gd-EOB-MRI).

METHODS

This retrospective study included 123 at-risk patients with 160 hepatic observations (HCCs, n = 116; non-HCC malignancies, n = 18; benign, n = 26) showing arterial phase hyper-enhancement (APHE) ≥ 1 cm at Gd-EOB-MRI. The mean time intervals from gadoxetic acid injection to PVP1 and PVP2 acquisitions were 53 ± 2 s and 73 ± 3 s, respectively. After evaluating image findings independently, imaging findings and diagnoses were finalized by a consensus of two radiologists using either PVP1 or PVP2 image sets according to the LI-RADS v2018 or EASL criteria. Sensitivity, specificity, and accuracy were compared.

RESULTS

Among HCCs, more washout and enhancing capsule were observed in PVP2 (83.6% and 27.6%) than in PVP1 (50.9% and 19.8%) (p < 0.001, both). The PVP2 set presented significantly higher sensitivity (83.6% vs. 53.5%, LI-RADS; 82.8% vs. 50.0%, EASL; p < 0.001, both) and accuracy (0.88 vs. 0.73, LI-RADS; 0.88 vs. 0.72, EASL; p < 0.001, both) than the PVP1 set without significant specificity loss (93.2% vs. 93.2%, by LI-RADS or EASL; p = 0.32, both). None of the non-HCC malignancy was non-invasively diagnosed as HCC in both PVP image sets.

CONCLUSION

Late acquisition of PVP detected washout and enhancing capsule of HCC more sensitively than early acquisition, enabling accurate diagnoses of HCC, according to LI-RADS or EASL criteria.

KEY POINTS

• Among HCCs, more washout and enhancing capsules were observed in PVP2 than PVP1, quantitatively and qualitatively. • The portal venous phase acquired at around 70 s after contrast media administration (PVP2) provided significantly higher sensitivity and AUC value than PVP1 by using LI-RADS v2018 or EASL criteria. • More HCCs were categorized as LR-5 in PVP2 than in PVP1 images, and the specificity of PVP2 (93.5%) was comparable with PVP1 (93.5%).

Magnetic Resonance Imaging With Extracellular Contrast Detects Hepatocellular Carcinoma With Greater Accuracy Than With Gadoxetic Acid or Computed Tomography

BACKGROUND & AIMS

Computed tomography (CT) and magnetic resonance imaging (MRI) are used to detect hepatocellular carcinoma (HCC). We performed a prospective study to compare the diagnostic performance of CT, MRI with extracellular contrast agents (ECA-MRI), and MRI with hepatobiliary agents (HBA-MRI) in the detection of HCC using the liver imaging reporting and data system (LI-RADS).

METHODS

We studied 125 participants (102 men; mean age, 55.3 years) with chronic liver disease who underwent CT, ECA-MRI, or HBA-MRI (with gadoxetic acid) before surgery for a nodule initially detected by ultrasound at a tertiary center in Korea, from November 2016 through February 2019. We collected data on major features and assigned LI-RADS categories (v2018) from CT and MRI examinations. We then compared the diagnostic performance for LR-5 for each modality alone, and in combination.

RESULTS

In total, 163 observations (124 HCCs, 13 non-HCC malignancies, and 26 benign lesions; mean size, 20.7 mm) were identified. ECA-MRI detected HCC with 83.1% sensitivity and 86.6% accuracy, compared to 64.4% sensitivity and 71.8% accuracy for CT (P < .001) and 71.2% sensitivity (P = .005) and 76.5% accuracy for HBA-MRI (P = .005); all technologies detected HCC with 97.4% specificity. Adding CT to either ECA-MRI (89.2% sensitivity, 91.4% accuracy; both P < .05) or HBA-MRI (82.8% sensitivity, 86.5% accuracy; both P < .05) significantly increased its diagnostic performance in detection of HCC compared with the MRI technologies alone. ECA-MRI identified arterial phase hyperenhancement in a significantly higher proportion of patients (97.6%) than CT (81.5%; P < .001) or HBA-MRI (89.5%; P = .002). ECA-MRI identified non-peripheral washout in 79.8% of patients, vs 74.2% of patients for CT and 73.4% of patients for HBA-MRI (differences not significant). ECA-MRI identified enhancing capsules in 85.5% of patients, vs 33.9% for CT (P < .001) and 41.4% for HBA-MRI (P < .001).

CONCLUSION

In a prospective study of patients with chronic liver disease and a nodule detected by ultrasound, ECA-MRI detected HCC with higher levels of sensitivity and accuracy than CT or HBA-MRI, based on LI-RADS. Diagnostic performance was best when CT was used in combination with MRI compared with MRI alone.

Evaluation of Primary Liver Cancers Using Hepatocyte-Specific Contrast-Enhanced MRI: Pitfalls and Potential Tips

When radiologists interpret hepatic focal lesions seen on dynamic magnetic resonance imaging (MRI) scans, it is important not only to distinguish malignant lesions from benign ones but also to distinguish nonhepatocellular carcinoma (HCC) malignancies from HCCs. In addition, most major guidelines, including those of the American Association for the Study of Liver Disease, European Association for the Study of the Liver, and Korean Liver Cancer Association and National Cancer Center, allow for the noninvasive imaging diagnosis of HCC in at-risk patients. However, ~40% of HCC cases show atypical imaging features mimicking non-HCC malignancies. Furthermore, several benign and malignant lesions, such as flash-filling hemangioma and intrahepatic mass-forming cholangiocarcinoma, frequently look like HCC. In contrast, although multiparametric MRI options, including hepatobiliary phase and diffusion-weighted imaging, provide useful information that could help address these challenges, there remain several unresolved issues with regard to the noninvasive diagnostic criteria characterizing HCC. In this article, we discuss the typical imaging features and challenging situations related to primary liver cancers in MRI, while considering how to make a correct diagnosis. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

Diagnostic Performance of CT/MRI Liver Imaging Reporting and Data System v2017 for Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

The liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing liver imaging in patients at high risk for hepatocellular carcinoma (HCC). We performed a meta-analysis to determine the diagnostic performance of the LR-5 category for HCC and the pooled proportions of HCCs in each LI-RADS category using CT/MRI LI-RADS v2017.

METHODS

We searched multiple databases for original studies reporting on the diagnostic accuracy of CT/MRI LI-RADS v2017. Random-effects models were used to determine the summary estimates of the diagnostic performance of the LR-5 category and the pooled proportions of HCCs for each LI-RADS category. Risk of bias and concerns regarding applicability were evaluated with the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

RESULTS

Fourteen studies (3 prospective studies and 11 retrospective studies) were included in the final analysis, consisting of 2056 patients, 2589 observations, and 1693 HCCs. The pooled per-observation sensitivity was 67% (95% confidence interval [CI], 62%-72%) with specificity of 92% (95% CI, 88%-95%) in the LR-5 category of CT/MRI LI-RADS v2017 for diagnosing HCC. The pooled proportions of HCCs were 0% (95% CI, 0%-0%) for LR-1, 4% (95% CI, 0%-8%) for LR-2, 34% (95% CI, 23%-44%) for LR-3, 67% (95% CI, 53%-81%) for LR-4, and 92% (95% CI, 87%-96%) for LR-5. The proportions of HCCs were significantly different among LI-RADS categories 1-5 (P = .034).

CONCLUSIONS

The LR-5 category of CT/MRI LI-RADS v2017 shows moderate sensitivity and high specificity for diagnosing HCC. Higher LI-RADS categories contained higher proportions of HCCs.

Multimodality Imaging of Hepatocellular Carcinoma: From Diagnosis to Treatment Response Assessment in Everyday Clinical Practice

The Liver Imaging Reporting and Data System (LI-RADS) is a recently developed classification aiming to improve the standardization of liver imaging assessment in patients at risk of developing hepatocellular carcinoma (HCC). The LI-RADS v2017 implemented new algorithms for ultrasound (US) screening and surveillance, contrast-enhanced US diagnosis and computed tomography/magnetic resonance imaging treatment response assessment. A minor update of LI-RADS was released in 2018 to comply with the American Association for the Study of the Liver Diseases guidance recommendations. The scope of this review is to provide a practical overview of LI-RADS v2018 focused both on the multimodality HCC diagnosis and treatment response assessment.

Comparison of extracellular and hepatobiliary MR contrast agents for the diagnosis of small HCCs

BACKGROUND & AIMS

The aim of this study was to use a head-to-head nodule comparison to compare the performance of extracellular contrast agent MRI (ECA-MRI) with that of hepatobiliary contrast agent MRI (HBA-MRI) for the non-invasive diagnosis of small hepatocellular carcinomas (HCCs).

METHODS

Between August 2014 and October 2017, 171 patients with cirrhosis, each with 1 to 3 nodules measuring 1-3 cm, were enrolled across 8 centers. All patients underwent both an ECA-MRI and an HBA-MRI within a month. A non-invasive diagnosis of HCC was made when a nodule exhibited arterial phase hyper-enhancement (APHE) with washout at the portal venous phase (PVP) and/or delayed phase (DP) for ECA-MRI, or the PVP and/or HB phase (HBP) for HBA-MRI. The gold standard was defined by using a previously published composite algorithm.

RESULTS

A total of 225 nodules, of which 153 were HCCs and 72 were not, were included. The sensitivites of both MRI techniques were similar. Specificity was 83.3% (95% CI 72.7-91.1) for ECA-MRI and 68.1% (95% CI 56.0-78.6) for HBA-MRI. In terms of HCC diagnosis on ECA-MRI, 138 nodules had APHE, 84 had washout at PVP, and 104 at DP; on HBA-MRI, 128 nodules had APHE, 71 had washout at PVP, and 99 at HBP. For nodules 2-3 cm in size, sensitivity and specificity were similar between the 2 approaches. For nodules 1-2 cm in size, specificity dropped to 66.1% (95% CI 52.2-78.2) for HBA-MRI vs. 85.7% (95% CI 73.8-93.6) for ECA-MRI.

CONCLUSIONS

HBA-MRI specificity is lower than that of ECA-MRI for diagnosing small HCCs in patients with cirrhosis. These results raise the question of the proper use of HBA-MRI in algorithms for the non-invasive diagnosis of small HCCs.

LAY SUMMARY

There are 2 magnetic resonance imaging (MRI)-based approaches available for the non-invasive diagnosis of hepatocellular carcinoma (HCC), using either extracellular or hepatobiliary contrast agents. The current results showed that the sensitivity of MRI with hepatobiliary contrast agents was similar to that with extracellular contrast agents, but the specificity was lower. Thus, hepatobiliary contrast agent-based MRI, although detailed in international guidelines, should be used with caution for the non-invasive diagnosis of HCC.

CLINICAL TRIAL NUMBER

NCT00848952.

Sirlin C, Song B, Taouli B, Yoshimitsu K, Koh DM. Consensus report from the 8th International Forum for Liver Magnetic Resonance Imaging

OBJECTIVES

The 8th International Forum for Liver Magnetic Resonance Imaging (MRI), held in Basel, Switzerland, in October 2017, brought together clinical and academic radiologists from around the world to discuss developments in and reach consensus on key issues in the field of gadoxetic acid-enhanced liver MRI since the previous Forum held in 2013.

METHODS

Two main themes in liver MRI were considered in detail at the Forum: the use of gadoxetic acid for contrast-enhanced MRI in patients with liver cirrhosis and the technical performance of gadoxetic acid-enhanced liver MRI, both opportunities and challenges. This article summarises the expert presentations and the delegate voting on consensus statements discussed at the Forum.

RESULTS AND CONCLUSIONS

It was concluded that gadoxetic acid-enhanced MRI has higher sensitivity for the diagnosis of hepatocellular carcinoma (HCC), when compared with multidetector CT, by utilising features of hyperenhancement in the arterial phase and hypointensity in the hepatobiliary phase (HBP). Recent HCC management guidelines recognise an increasing role for gadoxetic acid-enhanced MRI in early diagnosis and monitoring post-resection. Additional research is needed to define the role of HBP in predicting microvascular invasion, to better define washout during the transitional phase in gadoxetic acid-enhanced MRI for HCC diagnosis, and to reduce the artefacts encountered in the arterial phase. Technical developments are being directed to shortening the MRI protocol for reducing time and patient discomfort and toward utilising faster imaging and non-Cartesian free-breathing approaches that have the potential to improve multiphasic dynamic imaging.

KEY POINTS

• Gadoxetic acid-enhanced MRI provides higher diagnostic sensitivity than CT for diagnosing HCC. • Gadoxetic acid-enhanced MRI has roles in early-HCC diagnosis and monitoring post-resection response. • Faster imaging and free-breathing approaches have potential to improve multiphasic dynamic imaging.

Enhancement pattern of hepatocellular adenoma (HCA) on MR imaging performed with Gd-EOB-DTPA versus other Gd-based contrast agents (GBCAs): An intraindividual comparison

PURPOSE

To conduct an intraindividual comparison of the enhancement pattern of hepatocellular adenoma (HCA) on dynamic MRI study obtained following the injection of Gadoxetic acid (Gd-EOB-DTPA) and other gadolinium-based contrast agents (GBCAs).

METHOD

This is a retrospective, Institutional Review Board-approved study conducted in a single institution. A search of medical records between 2008 and 2017 revealed 17 patients (all females) with at least one pathologically-proven HCA who underwent liver MRI with Gd-EOB-DTPA and another GBCA within 1 year. Enhancement of each lesion on hepatic arterial (HAP), portal venous (PVP), 2 min and 4-5 minutes phases was subjectively evaluated by two abdominal radiologists. Lesions were categorized as hyper-, iso- or hypointense compared to the surrounding liver parenchyma. The presence of a peripheral pseudocapsule was also recorded. The differences in lesion enhancement were assessed using the McNemar Test. A p-value <0.05 was considered statistically significant.

RESULTS

The final population included 35 HCAs (83% inflammatory subtype). There was no significant difference in lesion size (P = 0.708) and enhancement on HAP (P = 0.625) or PVP (P = 0.125). HCAs showed more frequently hypointensity on 2 min (13/35 vs. 1/35, P < 0.001) and 4-5 minutes (P < 0.001) images obtained after injection of Gd-EOB-DTPA compared to those obtained after other GBCAs. A pseudocapsule was more frequently noted after administration of Gd-EOB-DTPA (13/35 vs 1/35, P = 0.002).

CONCLUSIONS

Enhancement pattern of HCA differs significantly after the injection of Gd-EOB-DTPA compared to other GBCAs. Lesion hypointensity on 2 min and 4-5 minutes images is more frequent when using Gd-EOB-DTPA.

Use of gadoxetate disodium in patients with chronic liver disease and its implications for liver imaging reporting and data system (LI-RADS)

Use of gadoxetate disodium, a hepatobiliary gadolinium-based agent, in patients with chronic parenchymal liver disease offers the advantage of improved sensitivity for detecting hepatocellular carcinoma (HCC). Imaging features of liver observations on gadoxetate-enhanced MRI may also serve as biomarkers of recurrence-free and overall survival following definitive treatment of HCC. A number of technical and interpretative pitfalls specific to gadoxetate exist, however, and needs to be recognized when protocoling and interpreting MRI exams with this agent. This article reviews the advantages and pitfalls of gadoxetate use in patients at risk for HCC, and the potential impact on Liver Imaging Reporting and Data System (LI-RADS) imaging feature assessment and categorization. Level of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;49:1236-1252.

Diagnostic Efficacy and Safety of Gadoxetate Disodium vs Gadobenate Dimeglumine in Patients With Known or Suspected Focal Liver Lesions: Results of a Clinical Phase III Study

Purpose:

The aim of this study is to evaluate the diagnostic efficacy and safety of gadoxetate disodium vs gadobenate dimeglumine in patients with known or suspected focal liver lesions.

Methods:

This was a prospective, multicenter, double-blind, randomized, inter-individual Phase III study. The primary target—technical efficacy—was already published. Here, secondary efficacy parameters—sensitivity and specificity—and safety in specific patient populations are presented. Patients with suspected or known focal liver lesions scheduled for contrast-enhanced liver magnetic resonance imaging (MRI) were recruited and categorized in 4 a priori specified subgroups: (1) all patients, (2) patients with liver cancer (hepatocellular carcinoma [HCC]), (3) patients with cirrhosis, and (4) patients with HCC + cirrhosis. Dual multi-detector liver computed tomography (CT) served as standard of reference.

Results:

A total of 295 patients were included. While the overall increase in sensitivity across all 4 patient groups was comparable for gadoxetate disodium (increase from pre- to post-contrast ranging from 6.2% to 9.9%) and gadobenate dimeglumine (ranging from −2.9% to 10.0%), significant differences were seen for some of the subgroups. There was a significantly higher increase in sensitivity for gadoxetate disodium in patients with HCC (7%) and HCC + cirrhosis (12.8%) in comparison with gadobenate dimeglumine. Specificity decreased for both agents: gadoxetate disodium by −2.8% to −6.3% and gadobenate dimeglumine by −3.3% to −8.7%. Gadoxetate showed a significantly lower loss of specificity in all subgroups. Safety was comparable in both groups.

Conclusions:

Gadoxetate disodium proved to be an effective liver-specific MRI contrast agent. Some distinct advantages over gadobenate dimeglumine were demonstrated in patients with HCC and patients with HCC + liver cirrhosis for sensitivity and specificity in liver lesion detection.

LI-RADS for CT diagnosis of hepatocellular carcinoma: performance of major and ancillary features

PURPOSE

To evaluate the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) v2017 major features, the impact of ancillary features, and categories on contrast-enhanced computed tomography (CECT) for the diagnosis of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This retrospective study included 59 patients (104 observations including 72 HCCs) with clinical suspicion of HCC undergoing CECT between 2013 and 2016. Two radiologists independently assessed major and ancillary imaging features for each liver observation and assigned a LI-RADS category based on major features only and in combination with ancillary features. The composite reference standard included pathology or imaging. Per-lesion estimates of diagnostic performance of major features, ancillary features, and LI-RADS categories were assessed by generalized estimating equation models.

RESULTS

Major features (arterial phase hyperenhancement, washout, capsule, and threshold growth) respectively had a sensitivity of 86.1%, 81.6%, 20.7%, and 26.1% and specificity of 39.3%, 67.9%, 89.9%, and 85.0% for HCC. Ancillary features (ultrasound visibility as discrete nodule, subthreshold growth, and fat in mass more than adjacent liver) respectively had a sensitivity of 42.6%, 50.8%, and 15.1% and a specificity of 79.2%, 66.9%, and 96.4% for HCC. Ancillary features modified the final category in 4 of 104 observations. For HCC diagnosis, categories LR-3, LR-4, LR-5, and LR-TIV (tumor in vein) had a sensitivity of 5.3%, 29.0%, 53.7%, and 10.7%; and a specificity of 49.1%, 84.4%, 97.3%, and 96.4%, respectively.

CONCLUSION

On CT, LR-5 category has near-perfect specificity for the diagnosis of HCC and ancillary features modifies the final category in few observations.

Comparison of gadoxetic acid versus gadopentetate dimeglumine for the detection of hepatocellular carcinoma at 1.5 T using the liver imaging reporting and data system (LI-RADS v.2017)

PURPOSE

The goal of this study was to investigate the Liver Imaging Reporting and Data System (LI-RADS) v.2017 for the categorization of hepatocellular carcinomas (HCCs) with gadoxetic acid compared with gadopentetate dimeglumine-enhanced 1.5-T magnetic resonance imaging (MRI).

MATERIAL AND METHODS

We included 141 high-risk patients with 145 pathologically-confirmed HCCs who first underwent gadopentetate dimeglumine-enhanced 1.5-T followed by gadoxetic acid-enhanced 1.5-T MRI. Two independent radiologists evaluated the presence or absence of major HCC features and assigned LI-RADS categories after considering ancillary features on both MRIs. Finally, the sensitivity of LI-RADS category 5 (LR-5) and the frequencies of major HCC features were compared between gadoxetic acid- and gadopentetate dimeglumine-enhanced 1.5-T MRI using the Wilcoxon test.

RESULTS

The sensitivity of LR-5 for diagnosing HCCs was significantly different between gadoxetic acid- and gadopentetate dimeglumine-enhanced MRI (73.8% [107/145] vs 26.2% [38/145], P < 0.001; 71% [103/145] vs 29% [42/145], P < 0.001 for reviewers 1 and 2, respectively). Among the major HCC LI-RADS features, capsule appearance was less frequently demonstrated on gadoxetic acid-enhanced MRI than on gadopentetate dimeglumine-enhanced MRI (3.4% [5/145] vs 5.5% [8/145], P = 0.793; 4.1% [6/145] vs 5.5% [8/145], P = 0.87 for reviewers 1 and 2, respectively), and the frequency of arterial hyperenhancement was not significantly different between gadoxetic acid and gadopentetate dimeglumine (89% [129/145] vs 89% [129/145], P = 1.000). In addition, the frequency of a washout appearance was less in the transitional phase (TP) than in the portal venous phase (PVP) on gadoxetic acid-enhanced MRI (43% [46/107] vs 57% [61/107], P = 0.367).

CONCLUSION

Gadoxetic acid-enhanced MRI showed a comparable sensitivity to gadopentetate dimeglumine-enhanced MRI for the diagnosis of HCCs, and LI-RADS category 4 (LR-4) hepatic nodules were upgraded to LR-5 when taking into account the major features according to LI-RADS v.2017.

Prospective Intraindividual Comparison of Magnetic Resonance Imaging With Gadoxetic Acid and Extracellular Contrast for Diagnosis of Hepatocellular Carcinomas Using the Liver Imaging Reporting and Data System

We intraindividually compared the efficacy of magnetic resonance imaging (MRI) with extracellular contrast agents (ECA-MRI) and MRI with hepatobiliary agents (HBA-MRI) for the diagnosis of hepatocellular carcinoma (HCC) using the Liver Imaging Reporting and Data System (LI-RADS). Between November 2016 and November 2017, we enrolled 91 patients with chronic liver disease who underwent both ECA-MRI and HBA-MRI within a 1-month interval for a first detected hepatic nodule on ultrasound. In total, 117 observations (95 HCCs, 19 benign lesions, and 3 other malignancies; median size, 18 mm) were identified with surgical resection. Two observers assessed two MRIs based on LI-RADS v2017, with consensus by a third observer. We then compared the diagnostic performance of LR-5 according to LI-RADS and modified LI-RADS. ECA-MRI had higher sensitivity (77.9% versus 66.3%) and accuracy (82.1% versus 72.6%) than HBA-MRI in the LR-5 category (P < 0.001). When applying either modified washout on the portal venous phase (PVP)/transitional phase (TP) of HBA-MRI or isointensity with a capsule during the PVP/delayed phase of ECA-MRI (illusional washout), 13 HCCs on HBA-MRI and 11 HCCs on ECA-MRI were correctly classified as HCC, while achieving 100% specificity. One cholangiocarcinoma was accurately classified only with HBA-MRI due to its targetoid appearance in the TP and hepatobiliary phase. Conclusion: ECA-MRI showed better sensitivity and accuracy than HBA-MRI for the diagnosis of HCC with LI-RADS. We achieved better diagnostic performance when applying a modified washout on PVP/TP HBA-MRI and an illusional washout on ECA-MRI than we did with conventional criteria.

The capsule appearance of hepatocellular carcinoma in gadoxetic acid-enhanced MR imaging: Correlation with pathology and dynamic CT

This study aimed to evaluate the capability of gadoxetic acid-enhanced MR (GAeMR) to detect presence of capsule appearance in hepatocellular carcinoma (HCC), and to correlate it with dynamic computed tomography (CT) and pathological features.Sixty-three patients (54: 9 = M: F, mean age 55.8) surgically confirmed HCCs with preoperative CT and GAeMR were included in this retrospective study. Two readers evaluated presence of capsule appearances on CT and GAeMR images in each phase including precontrast (Pre), portal phase (PP), delayed phase (DP), transitional phase (TP), and hepatobiliary phase (HBP). Histologic capsule was compared with CT and GAeMR. Diagnostic performance of CT and GAeMR of each phase for histologic capsule was evaluated and compared by receiver operating characteristic curve. Interobserver agreement was assessed with kappa statistics.Histologically the capsule was complete in 12.7% (8/63) and incomplete in 60.3% (38/63). Four cases (6.3%) were pseudocapsule. Interobserver agreement for capsule appearance on GAeMR was good in Pre (κ = 0.684), moderate in PP (κ = 0.434), poor in TP (κ = 0.187), fair in HBP (κ = 0.395), and moderate on CT in PP (κ = 0.476) and DP (κ = 0.485). Diagnostic performance and sensitivity for the histologic capsule in DP on CT was highest among PP on CT and other phases on GAeMR. DP on CT images showed a higher Az value than PP on CT images with statistical significance (P < .001). PP on MR images revealed higher Az value than PP on CT images.The capsule appearance was most frequently observed in the DP on CT with highest diagnostic performance, and so DP images should be obtained on CT study for liver mass categorization. GAeMR yielded comparable capsule appearance to CT with moderate interobserver agreement. Considering hypointense rim on the HBP as fibrous capsule on pathology should be refrained, and so further study is warranted to correlate HBP hypointense rim with pathologic findings.

Intra-individual comparison of hepatocellular carcinoma imaging features on contrast-enhanced computed tomography, gadopentetate dimeglumine-enhanced MRI, and gadoxetic acid-enhanced MRI

Background Gadoxetic acid is being widely used for detection and characterization of hepatic nodules. However, there are no data regarding intra-individual comparison of imaging features of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT), gadopentetate dimeglumine-enhanced magnetic resonance imaging (Gd-DTPA-MRI), and gadoxetic acid-enhanced MRI (Gd-EOB-MRI). Purpose To evaluate typical imaging features of HCC and capsule appearance with dynamic CT, Gd-DTPA-MRI, and Gd-EOB-MRI. Material and Methods We retrospectively reviewed 56 HCCs in 49 patients. Lesion attenuation/signal intensity was graded using a five-point scale based on dynamic phase and hepatobiliary phase (HBP) imaging. Subjective washout and capsule appearance were evaluated on portal venous phase (PVP) or delayed/transitional phase (DP/TP) imaging. The tumor-to-liver contrast ratio (TLCR) was calculated. Results Gd-DTPA-MRI and Gd-EOB-MRI was graded higher than CT on arterial phase ( P < 0.001). Gd-EOB-MRI was graded lower than Gd-DTPA-MRI on PVP and DP/TP ( P < 0.05). The detection rate of subjective washout and capsule appearance did not differ among the three imaging studies on either PVP or DP/TP. TLCR of Gd-EOB-MRI was lower than CT on PVP ( P = 0.004) and was lower than Gd-DTPA-MRI on DP/TP ( P = 0.001). Conclusion Arterial phase hyperenhancement and washout appearance of HCC were well demonstrated in Gd-EOB-MRI. The detection of capsule appearance using Gd-EOB-MRI was not inferior to Gd-DTPA-MRI or CT.

Comparison of Visualization Rates of LI-RADS Version 2014 Major Features With IV Gadobenate Dimeglumine or Gadoxetate Disodium in Patients at Risk for Hepatocellular Carcinoma

OBJECTIVE

The purpose of this study is to compare visualization rates of the major features covered by Liver Imaging Reporting and Data System (LI-RADS) version 2014 in patients at risk for hepatocellular carcinoma using either gadobenate dimeglumine or gadoxetate disodium IV contrast agent.

MATERIALS AND METHODS

This retrospective study included liver MRI examinations performed with either gadobenate dimeglumine or gadoxetate disodium contrast enhancement. Using age, sex, underlying liver disease, and presence of cirrhosis, patients were placed into matched cohorts. All hepatic nodules 1 cm or larger (up to five per subject) were included, resulting in 63 subjects with 130 nodules (median nodule size, 1.9 cm) imaged with gadobenate and 64 subjects with 117 nodules (median nodule size, 2.0 cm) imaged with gadoxetate. Three radiologists reviewed the studies for LI-RADS major features independently. Bootstrap resampling with 10,000 repetitions was used to compare feature detection rates.

RESULTS

Arterial phase hyperenhancement was seen in a similar number of nodules with gadobenate dimeglumine (mean, 91.5% [119/130]) and gadoxetate disodium (mean, 88.0% [103/117]) (p = 0.173). Dynamic phase washout was more commonly seen with gadobenate dimeglumine (mean, 60.2% [78.3/130]) than with gadoxetate disodium (mean, 45.3% [53/117]) (p = 0.006). The capsule feature was more often visualized with gadobenate dimeglumine (mean, 50.2% [65.3/130]) than with gadoxetate disodium (mean, 33.3% [39/117]) (p < 0.001). Interreader agreement for arterial phase enhancement and dynamic phase washout was almost perfect for both contrast agents (κ > 0.83). Agreement for the capsule feature was moderate for gadobenate dimeglumine (κ = 0.52) and substantial for gadoxetate disodium (κ = 0.67).

CONCLUSION

The rates of visualization of arterial phase hyperenhancement are similar in studies performed with gadobenate dimeglumine and gadoxetate disodium, but dynamic phase washout and capsule appearance are more commonly visualized with gadobenate dimeglumine.

LI-RADS® ancillary features on CT and MRI

The Liver Imaging Reporting and Data System (LI-RADS) uses an algorithm to assign categories that reflect the probability of hepatocellular carcinoma (HCC), non-HCC malignancy, or benignity. Unlike other imaging algorithms, LI-RADS utilizes ancillary features (AFs) to refine the final category. AFs in LI-RADS v2017 are divided into those favoring malignancy in general, those favoring HCC specifically, and those favoring benignity. Additionally, LI-RADS v2017 provides new rules regarding application of AFs. The purpose of this review is to discuss ancillary features included in LI-RADS v2017, the rationale for their use, potential pitfalls encountered in their interpretation, and tips on their application.

Comparison of US Strain Elastography and Entero-MRI to Typify the Mesenteric and Bowel Wall Changes during Crohn's Disease: A Pilot Study

Purpose

To evaluate and compare the mesenteric and bowel wall changes during Crohn's disease (CD) on ultrasonography (US) Strain Elastography (SE) and Enterography Magnetic Resonance Imaging (E-MRI).

Methods

From July 2014 to September 2016, 35 patients with ileocolonoscopy diagnosis of CD were prospectively examined with E-MRI and in the same time with US and SE.

Results

A total of 41 affected bowel segments and 35 unaffected bowel segments in 35 patients were evaluated. US-SE color-scale coding showed a blue color pattern in the fibrotic mesentery and bowel wall in 15 patients and a green color pattern in the edematous ones in 20 patients. The signal of the bowel wall and mesenteric fat was iso/hypointense on T2-weighted sequence in the fibrotic pattern (23/35 and 12/35 patients) and hyperintense in the edematous pattern (12/35 and 23/35 patients). Mean ADC values were, respectively, 2,58 ± 0,33 × 10⁻³ for the fibrotic mesentery and 2,14 ± 0,28 × 10⁻³ for edematous one. There was a statistical correlation between US-SE color-scale and T2 signal intensity and between the US-SE color-scale and ADC maps.

Conclusions

US-SE, ADC, and signal intensity on T2-weighted sequences on MR prove to be useful tools for the evaluation of CD pattern.

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

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

Critical analysis of the major and ancillary imaging features of LI-RADS on 127 proven HCCs evaluated with functional and morphological MRI: Lights and shadows

PURPOSE

To report a critical analysis of major and ancillary MR imaging features in assessment of HCC.

METHODS

Retrospectively we evaluated 70 cirrhotic patients with 173 nodules, which were subjected to MR study at 0 time (MR0), after 3 (MR3) and 6 months (MR6) using two different contrast media. EOB-GD-DTPA was injected at MR0 and MR6, while Gd-BT-DO3A at MR3. Three expert hepatic radiologists reviewed all images, recording, according to LI-RADS, the size, the presence and quality of arterial-phase hyperenhancement, washout and capsule appearance, threshold growth. Additionally, we recorded signal intensity (SI) on T2-W images, on DWI, on apparent diffusion coefficient (ADC) maps and SI on T1-W images of EOB-GD-BPTA hepatospecific phase. Median value of ADC and of Intravoxel incoherent motion related parameters were assessed.

RESULTS

127 HCCs and 24 dysplastic nodules were assessed. Hypervascular on arterial phase was found in 84 HCCs, washout appearance in 124, capsule appearance in 111, hypointensity on hepatospecific phase in 127, hyperintensity on T2-W sequences and restricted diffusion in 107. Hyper vascular on arterial phase was found in 17 dysplastic nodules, wash-out appearance in 2, hypointensity on hepatospecific phase in 7 while no dysplastic nodules showed capsule appearance, hyperintensity on T2-W and restricted diffusion. Highest accuracy was obtained by washout appearance and hypointense signal on hepatospecific phase (97% and 95%).

CONCLUSIONS

Hypointensity on hepatospecific phase and washout appearance are the most relevant diagnostic sign for differentiating low-risk from high-risk HCC nodules. The capsule appearance, T2-W hyperintensity and restricted diffusion have high positive predictive value.