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This multi-center, retrospective study focused on periampullary cancer patients undergoing MRI for hepatic metastasis and abscess differentiation. T1-weighted, T2-weighted, and arterial phase images were utilized to create radiomics models. In the training-set, 112 lesions in 54 patients (median age [IQR, interquartile range], 73 [63-80]; 38 men) were analyzed, and 123 lesions in 55 patients (72 [66-78]; 34 men) comprised the validation set. The T1-weighted + T2-weighted radiomics model showed the highest AUC (0.82, 95% CI 0.75-0.89) in the validation set. Notably, < 30% T1-T2 size discrepancy in MRI findings predicted metastasis (Ps ≤ 0.037), albeit with AUCs of 0.64-0.68 for hepatic metastasis. The radiomics model enhanced radiologists' performance (AUCs, 0.85-0.87 vs. 0.80-0.84) and significantly increased diagnostic confidence (P < 0.001). Although the performance increase lacked statistical significance (P = 0.104-0.281), the radiomics model proved valuable in differentiating small hepatic lesions and enhancing diagnostic confidence. This study highlights the potential of MRI-based radiomics in improving accuracy and confidence in the diagnosis of periampullary cancer-related hepatic lesions., (© 2024. The Author(s).)

Background & Aims: Fatty change is commonly observed in hepatocellular carcinoma (HCC); however, the characteristics of steatotic and steatohepatitic HCCs are not well understood., Methods: This retrospective study included patients with HCCs who underwent resection between January 2014 and December 2019 to evaluate clinicopathological and magnetic resonance imaging features. Tumours were categorized as magnetic resonance imaging-steatotic, pathology-steatotic and steatohepatitic HCCs and were defined as HCCs with ≥50% steatosis on in-and-oppose phase images, ≥34% tumour cells with lipid droplets and ≥50% tumour areas with steatohepatitic features on light microscopy respectively., Results: Of 465 HCCs, 38 (8%), 23 (5%) and 15 (3%) were diagnosed as magnetic resonance imaging-steatotic, pathology-steatotic and steatohepatitic HCCs respectively. These HCC variants were less likely to be associated with hepatitis B virus infections than with type 2 diabetes mellitus, metabolic syndrome, non-tumour liver steatosis and steatohepatitis. Moreover, microvascular invasion was less likely to be associated with them than either tumour size or differentiation. Type 2 diabetes and non-tumour steatosis were independent risk factors for magnetic resonance imaging-steatotic HCCs. Pathology-steatotic HCCs and steatohepatitic HCCs were significantly associated with magnetic resonance imaging-steatotic HCCs. A targetoid appearance in the transitional or hepatobiliary phase was also more prevalent in steatohepatitic-HCCs than in non-steatohepatitic-HCCs. When magnetic resonance imaging-steatotic HCCs were combined with one or more ancillary features, the sensitivity and specificity were 60% and 97% respectively., Conclusion: Underlying fatty liver disease and metabolic syndrome are strongly associated with both steatotic and steatohepatitic HCCs. Clinicoradiological characteristics help identify steatohepatitic HCC with high specificity., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Sonazoid, a second-generation ultrasound contrast agent, was introduced for the diagnosis of hepatic nodules. To clarify the issues with Sonazoid contrast-enhanced ultrasonography for the diagnosis of hepatocellular carcinoma (HCC), the Korean Society of Radiology and Korean Society of Abdominal Radiology collaborated on the guidelines. The guidelines are de novo, evidence-based, and selected using an electronic voting system for consensus. These include imaging protocols, diagnostic criteria for HCC, diagnostic value for lesions that are inconclusive on other imaging results, differentiation from non-HCC malignancies, surveillance of HCC, and treatment response after locoregional and systemic treatment for HCC., Competing Interests: Min Woo Lee, Jung Hoon Kim, Ijin Joo, So Yeon Kim, Yong Eun Chung, Jeong Min Lee, contributing editors of the Korean Journal of Radiology, were not involved in the editorial evaluation or decision to publish this article. Woo Kyoung Jeong received honorarium from GE Healthcare and Bayer; Hyo-Jin Kang received honorarium from GE Healthcare; Mi-Suk Park received grant from GE Healthcare and Guerbet; Bohyun Kim was a consultant for Samsung Medison; Min Woo Lee received honorarium from Bracco, Starmed, Bonston Scientific, and Medtronic, and was a consultant for Starmed and Medtronic; Jeong Ah Hwang received honorarium from GE Healthcare; Jae Young Lee received grant from Canon Healthcare, Siemens Healthcare, Alpinion Medical System, and GE Healthcare and received honorarium from Philips, Canon Healthcare, GE Healthcare, Alpinion Medical System, and Siemens Healthcare; Jung Hoon Kim received honorarium from GE Healthcare; Ijin Joo received honorarium from Samsung Medison; So Yeon Kim received grant from Bayer Healthcare and Canon Healthcare; Jeong Min Lee received grant from Bayer Healthcare, Canon Healthcare, Siemens Healthcare, GE Healthcare, CMS, Guerbet, Samsung Medison, Starmed, RF medical, Clarify, and Dongkuk Pharma and received honorarium from Samsung Medison, Philips, GE Healthcare, Bayer, Guerbet, and Clarify. The funders had no role in the data analysis, or the decision to publish. All remaining authors have declared no conflicts of interest., (Copyright © 2023 The Korean Society of Radiology.)

Background/aims: To compare the performance of the Liver Imaging Reporting and Data System (LI-RADS) v2018 and Korean Liver Cancer Association-National Cancer Center (KLCA-NCC) 2018 criteria for diagnosing hepatocellular carcinoma (HCC) using magnetic resonance imaging (MRI) with hepatobiliary agent (HBA)., Methods: We searched the MEDLINE and EMBASE for studies from January 1, 2018, to October 20, 2021, that compared the diagnostic performance of two imaging criteria on HBA-MRI. A bivariate random-effects model was fitted to calculate the per-observation sensitivity and specificity, and the estimates of paired data were compared. Subgroup analysis was performed based on the observation size. Meta-regression analysis was also performed for study heterogeneity., Results: Of the six studies included, the pooled sensitivity of the definite HCC category of the KLCA-NCC criteria (82%; 95% confidence interval [CI], 74% to 90%; I 2 =84%) was higher than that of LR-5 of LI-RADS v2018 (65%; 95% CI, 52% to 77%; I 2 =96%) for diagnosing HCC (p<0.001), while the specificity was lower for KLCA-NCC criteria (87%; 95% CI, 84% to 91%; I 2 =0%) than LI-RADS v2018 (93%; 95% CI, 91% to 96%; I 2 =0%) (p=0.017). For observations sized ≥20 mm, the sensitivity was higher for KLCA-NCC 2018 than for LI-RADS v2018 (84% vs 74%, p=0.012), with no significant difference in specificity (81% vs 85%, p=0.451). The reference standard was a significant factor contributing to the heterogeneity of sensitivities., Conclusions: The definite HCC category of KLCA-NCC 2018 provided a higher sensitivity and lower specificity than the LR-5 of LI-RADS v2018 for diagnosing HCC using MRI with HBA.

Objectives: We aimed to investigate the optimal radiologic method to determine Milan criteria (MC) for the prediction of recurrence in patients who underwent locoregional treatment (LRT) for hepatocellular carcinoma (HCC) and subsequent liver transplantation (LT)., Methods: This retrospective study included 121 HCC patients who underwent LRT and had both liver dynamic CT and MRI. They were classified with MC using four cross combinations of two imaging modalities (CT and MRI) and two diagnostic criteria (modified Response Evaluation Criteria in Solid Tumors [mRECIST] and Liver Imaging Reporting and Data System treatment response algorithm [LI-RADS TRA]). Competing risk regression was performed to analyze the time to recurrence after LT. The predictive abilities of the four methods for recurrence were evaluated using the time-dependent area under the curve (AUC)., Results: Competing risk regression analyses found that beyond MC determined by MRI with mRECIST was independently associated with recurrence (hazard ratio, 6.926; p = 0.001). With mRECIST, MRI showed significantly higher AUCs than CT at 3 years and 5 years after LT (0.597 vs. 0.756, p = 0.012 at 3 years; and 0.588 vs. 0.733, p = 0.024 at 5 years). Using the pathologic reference standard, MRI with LI-RADS TRA showed higher sensitivity (61.5%) than CT with LI-RADS TRA (30.8%, p < 0.001) or MRI with mRECIST (38.5%, p < 0.001)., Conclusions: MRI with mRECIST was the optimal radiologic method to determine MC for the prediction of post-LT recurrence in HCC patients with prior LRT., Key Points: • MRI with modified RECIST (mRECIST) is the optimal preoperative method to determine Milan criteria for the prediction of post-transplant HCC recurrence in patients with prior locoregional treatment. • With mRECIST, MRI was better than CT for the prediction of post-transplant recurrence., (© 2022. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: We performed a meta-analysis to determine the probability of hepatocellular carcinoma (HCC) and non-HCC malignancies in Liver Imaging Reporting and Data System (LI-RADS) category M (LR-M) observations and the frequency of defined LR-M imaging features on MRI using LI-RADS v2018., Methods: We searched the MEDLINE and EMBASE databases to identify studies published from 1 January 2018 to 16 March 2021 reporting the probability of category LR-M in HCC and non-HCC malignancies on MRI. The pooled percentages of HCC and non-HCC malignancies in the LR-M observations were evaluated. Meta-regression analysis was performed to identify factors for study heterogeneity. The frequencies of defined LR-M imaging features were also calculated. Risk of bias and concerns regarding applicability were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool., Results: We identified 18 studies reporting the diagnostic performance of the LR-M category (3,812 observations in 3,615 patients), with nine studies reporting the frequencies of LR-M imaging features. The pooled percentages of HCC and non-HCC malignancies in the LR-M observations were 29% (95% confidence interval [CI], 21-38%) and 67% (95%CI, 57-77%), respectively. The study type and inclusion of benign lesions were significant factors for study heterogeneity. Of the 10 LR-M imaging features, rim arterial phase hyperenhancement (APHE) showed the highest frequency in non-HCC malignancies (68%; 95%CI, 61-75%)., Conclusions: The LR-M category was commonly used to characterize non-HCC malignancies, but also included 29% of HCC. The frequencies of the different LR-M imaging features were variable, with rim APHE showing the highest frequency in non-HCC malignancies., Key Points: • In the LR-M category using LI-RADS v2018 for MRI, the pooled percentage of malignancies in general was 96%, with 29% HCC and 67% non-HCC malignancies, while the remaining 4% was benign entity. • The study type and inclusion of benign lesions were significant factors contributing to substantial heterogeneity among included studies. • The frequencies of the different LR-M imaging features were variable, with rim APHE showing the highest frequency in non-HCC malignancies., (© 2021. The Author(s), under exclusive licence to European Society of Radiology.)

Background: The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing liver imaging in patients at risk for hepatocellular carcinoma (HCC)., Purpose: To systematically compare the performance of computed tomography (CT)/MRI LI-RADS category 5 (LR-5) for diagnosing HCC between versions 2017 and 2018., Study Type: Systematic review and meta-analysis., Subjects: Six articles with 1181 lesions., Field Strength/sequence: 1.5 T and 3.0 T., Assessment: Data extraction was independently performed by two reviewers who identified and reviewed articles comparing the performance of LR-5 for diagnosing HCC between CT/MRI LI-RADS versions 2017 and 2018. Study and patient characteristics, index test characteristics, reference standards, and study outcomes were extracted from included studies. Risk of bias and concerns regarding applicability were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool., Statistical Tests: Bivariate random-effects models were used to calculate the pooled per-observation sensitivity and specificity of LR-5 using both versions. The summary receiver operating characteristic curves were plotted. Meta-regression analysis was performed to explore heterogeneity. A P-value <0.05 was considered to be statistically significant for all analyses other than heterogeneity, where the significance threshold was 0.1., Results: The pooled per-observation sensitivity of LR-5 for diagnosing HCC did not show statistically significant difference between versions 2017 (60%; 95% confidence interval [CI], 49%-70%) and 2018 (67%; 95% CI, 56%-76%; P = 0.381). The pooled per-observation specificities of LR-5 were not significantly different between versions 2017 (92%; 95% CI, 90%-95%) and 2018 (91%; 95% CI, 88%-93%; P = 0.332). Meta-regression analyses revealed that the most common underlying liver disease (hepatitis B or hepatitis C) was a significant factor contributing to the heterogeneity of sensitivities among studies for both versions., Data Conclusion: In this meta-analysis using intraindividual paired comparisons, the pooled sensitivity and pooled specificity of LR-5 were not significantly different between 2017 and 2018 LI-RADS versions., Level of Evidence: 3 TECHNICAL EFFICACY: Stage 2., (© 2021 International Society for Magnetic Resonance in Medicine.)

Background: According to the Liver Imaging Reporting and Data System (LI-RADS), the LI-RADS category M (LR-M), which are probably or definitely malignant but are not specific for hepatocellular carcinomas (HCCs), does not exclude HCCs. A gap in knowledge remains, including their characteristics and recurrence of HCCs categorized as LR-M., Purpose: To compare the characteristics of HCCs categorized as LR-M with HCCs categorized as LR-4 or LR-5 (LR-4/5) using the LI-RADS version 2018 and evaluate the relationship of these categories with the risk of early recurrence after curative resections of single HCCs., Study Type: Retrospective., Subjects: Two hundred and eighty-one patients (mean age, 57 years; 191 men and 90 women) who underwent curative resections for single HCCs and preoperative contrast-enhanced MRI between 2015 and 2017., Field Strength/sequence: 3T Dual gradient-echo T 1 WI with in- and opposed-phase, turbo spin-echo T 2 WI, diffusion-weighted echo-planar images, and three-dimensional gradient-echo T 1 WI before and after administration of contrast agent., Assessment: MRI features according to the LI-RADS version 2018 were evaluated and LI-RADS category were assigned for each observation. Clinical, imaging, and histopathological features were compared based on LI-RADS categorization. Early recurrence rates (<2 years) and associated factors were also evaluated., Statistical Tests: Fisher's exact test, two-sample t test after satisfying assumption of normality through Shapiro-Wilk test, Fleiss κ coefficient, Cox proportional hazards regression analysis, Kaplan-Meier method, and log-rank test., Results: Forty-one HCCs (14.6%) were categorized as LR-M and 240 HCCs (85.4%) were categorized as LR-4/5. LR-M HCCs showed poorer differentiation than LR-4/5 HCCs. In the multivariate analysis, the LR-M category was an independent predictor for early recurrence (hazard ratio, 1.904; 95% confidence interval, 1.024-3.542; P < 0.05). Early recurrence rates were significantly higher in patients with LR-M HCCs than in patients with LR-4/5 HCCs (32.0% vs. 18.4%, respectively, P < 0 05)., Data Conclusion: Compared to LR-4/5 HCCs, LR-M HCCs were associated with poorer tumor differentiation and higher early recurrence rates after curative resections of single HCCs., Level of Evidence: 3 Technical Efficacy Stage: 2., (© 2021 International Society for Magnetic Resonance in Medicine.)

Objective: Based on the Liver Imaging Reporting and Data System version 2018 (LI-RADS, v2018), this study aimed to analyze LR-5 diagnostic performance for hepatocellular carcinoma (HCC) when threshold growth as a major feature is replaced by a more HCC-specific ancillary feature, as well as the frequency of threshold growth in HCC and non-HCC malignancies and its association with tumor size., Materials and Methods: This retrospective study included treatment-naive patients who underwent gadoxetate disodium-enhanced MRIs for focal hepatic lesions and surgery between January 2009 and December 2016. The frequency of major and ancillary features was evaluated for HCC and non-HCC malignancies, and the LR-category was assessed. Ancillary features that were significantly more prevalent in HCC were then used to either replace threshold growth or were added as additional major features, and the diagnostic performance of the readjusted LR category was compared to the LI-RADS v2018., Results: A total of 1013 observations were analyzed. Unlike arterial phase hyperenhancement, washout, or enhancing capsule which were more prevalent in HCCs than in non-HCC malignancies (521/616 vs. 18/58, 489/616 vs. 19/58, and 181/616 vs. 5/58, respectively; p < 0.001), threshold growth was more prevalent in non-HCC malignancies than in HCCs (11/23 vs. 17/119; p < 0.001). The mean size of non-HCC malignancies showing threshold growth was significantly smaller than that of non-HCC malignancies without threshold growth (22.2 mm vs. 42.9 mm, p = 0.040). Similar results were found for HCCs; however, the difference was not significant (26.8 mm vs. 33.1 mm, p = 0.184). Additionally, Fat-in-nodule was more frequent in HCCs than in non-HCC malignancies (99/616 vs. 2/58, p = 0.010). When threshold growth and fat-in-nodule were considered as ancillary and major features, respectively, LR-5 sensitivity (73.2% vs. 73.9%, p = 0.289) and specificity (98.2% vs. 98.5%, p > 0.999) were comparable to the LI-RADS v2018., Conclusion: Threshold growth is not a significant diagnostic indicator of HCC and is more common in non-HCC malignancies. The diagnostic performance of LR-5 was comparable when threshold growth was recategorized as an ancillary feature and replaced by a more HCC-specific ancillary feature., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2021 The Korean Society of Radiology.)

Herein, we assessed whether hepatobiliary phase (HBP) signal intensity (SI) can be used to differentiate HCC and non-HCC malignancies within LR-M observations. 106 LR-M patients based on LI-RADS v2018 who underwent gadoxetate-disodium magnetic resonance imaging and surgery from January 2009 to December 2018 were included. SI of LR-M observation on HBP was analyzed by two radiologists and categorized into dark, low and iso-to-high groups. Tumor was classified as dark when more than 50% of tumor showed hypointensity compared to spleen, as low when more than 50% of tumor showed hyperintensity compared to spleen but hypointensity compared to liver parenchyma, and as iso-to-high if there was even a focal iso-intensity or hyperintensity compared to liver parenchyma. Analysis of clinicopathological factors and association between imaging and histology was performed. Out of 106 LR-M, 42 (40%) were showed dark, 61 (58%) showed low, and 3 (3%) showed iso-to-high SI in HBP. Three iso-to-high SI LR-M were HCCs (P = 0.060) and their major histologic differentiation was Edmondson grade 1 (P = 0.001). 43 out of 61 (71%) low SI LR-M were iCCA or cHCC-CCA (P = 0.002). Inter-reader agreement of HBP SI classification was excellent, with a kappa coefficient of 0.872. LR-M with iso-to-high SI in HBP is prone to being HCC while LR-M with low SI in HBP is prone to being tumor with fibrous stroma such as iCCA and cHCC-CCA. Classification of LR-M based on HBP SI may be a helpful method of differentiating HCC from non-HCC malignancies., Competing Interests: The authors have declared that no competing interests exist.

Background: The reported diagnostic performance for hepatocellular carcinoma (HCC) of each major imaging feature on MRI using standardized definitions of the Liver Imaging Reporting and Data System (LI-RADS) is variable. It is important to know the actual performance of each LI-RADS major imaging feature for imaging diagnosis of HCC and determine the sources of heterogeneity between the reported results., Purpose: To systematically determine the performance of each major imaging feature of LI-RADS for diagnosing HCC using either extracellular contrast agent-enhanced MRI (ECA-MRI) or gadoxetate disodium-enhanced MRI (EOB-MRI)., Study Type: Systematic review and meta-analysis., Subjects: Sixteen original articles with 3542 lesions., Field Strength: A 1.5 T and 3.0 T., Assessment: Data extraction was independently performed by two reviewers who identified and reviewed original articles reporting the diagnostic performance of each LI-RADS major imaging feature-arterial phase hyperenhancement (APHE), observation size, washout appearance, enhancing "capsule," and threshold growth-using MRI. Study characteristics, study population characteristics, MRI characteristics, contrast agent, LI-RADS version, reference standards, and study outcomes were extracted from included studies. Risk of bias and concerns regarding applicability were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool., Statistical Tests: Bivariate random-effects models were used to obtain summary estimates of the diagnostic performance of each LI-RADS major imaging feature. Hierarchical summary receiver operating characteristic curves were plotted. Meta-regression analyses were performed to explore potential sources of heterogeneity., Results: The pooled per-observation sensitivities and specificities for diagnosing HCC were 85% (95% confidence interval [CI] = 78%-89%) and 57% (95% CI = 44%-70%) for arterial phase hyperenhancement (APHE), 77% (95% CI = 72%-82%), and 74% (95% CI = 63%-83%) for washout appearance, and 52% (95% CI = 41%-64%) and 90% (95% CI = 85%-94%) for enhancing "capsule," respectively., Data Conclusions: Among the LI-RADS major features, the sensitivity was the highest for APHE and the specificity was the highest for enhancing "capsule" in the diagnosis of HCC., Evidence Level: 3 TECHNICAL EFFICACY: Stage 2., (© 2021 International Society for Magnetic Resonance in Medicine.)

Objectives: This study aimed to assess the detection of hepatocellular carcinoma (HCC) utilizing subtraction AP (arterial phase) imaging only for T1 hyperintense observations compared with the detection of HCC on subtraction AP imaging that included T1 hyper-, iso-, and hypointense lesions on gadoxetate disodium-enhanced MRI., Materials and Methods: This retrospective study included 234 patients (311 observations including 239 HCCs) at high risk for HCC who underwent gadoxetate disodium-enhanced MRI with subtraction AP imaging between 2015 and 2017. Arterial phase hyperenhancement (APHE) was divided into two subtypes: conventional APHE, where subtraction AP imaging is used to detect APHE only for T1 hyperintense observations; and modified APHE, where subtraction AP imaging is applied to T1 hyper-, iso-, and hypointense lesions. Two readers independently reviewed all observations and the per-observation diagnostic performances were compared using McNemar's test., Results: Modified nonrim APHE showed significantly higher sensitivity than conventional nonrim APHE (90.0% vs 82.8%; p < 0.001) for diagnosing HCC, without a significant difference in specificity (66.7% vs 68.1%; p > 0.999). The LR-5 category with modified nonrim APHE provided better sensitivity than the LR-5 with conventional nonrim APHE (70.3% vs 63.2%; p < 0.001), without a significant decrease in specificity (94.4% vs 95.8%; p > 0.999)., Conclusion: Extended application of subtraction AP imaging for T1 hypo- or isointense observations on gadoxetate disodium-enhanced MRI can improve sensitivity in the diagnosis of HCC without a significant difference in specificity., Key Points: • Modified nonrim arterial phase hyperenhancement (APHE), extended application of subtraction arterial phase imaging for T1 hypo- or isointense observation, outperforms conventional nonrim APHE. • The LR-5 category with modified nonrim APHE provided better sensitivity in diagnosing HCC than the LR-5 with conventional APHE, without a significant decrease in specificity.

Objective: To investigate the feasibility of using amide proton transfer (APT) magnetic resonance imaging (MRI) in the liver and to evaluate its ability to characterize focal liver lesions (FLLs)., Methods: A total of 203 patients with suspected FLLs who underwent APT imaging at 3T were included. APT imaging was obtained using a single-slice turbo spin-echo sequence to include FLLs through five breath-holds, and its acquisition time was approximately 1 min. APT signals in the background liver and FLL were measured with magnetization transfer ratio asymmetry (MTR asym ) at 3.5 ppm. The technical success rate of APT imaging and the reasons for failure to obtain meaningful MTR asym values were assessed. The Mann Whitney U test was used to compare MTR asym values between different FLLs., Results: The technical success rate of APT imaging in the liver was 62.1% (126/203). The reasons for failure were a too large B 0 inhomogeneity (n = 43), significant respiratory motion (n = 12), and these two factors together (n = 22), respectively. Among 59 FLLs with analyzable APT images, MTR asym values were compared between 27 patients with liver metastases and 23 patients with hepatocellular carcinomas (HCCs). The MTR asym values of metastases were significantly higher than those of HCC (0.13 ± 2.15% vs. - 1.41 ± 3.68%, p = 0.027)., Conclusions: APT imaging could be an imaging biomarker for the differentiation of FLLs. However, further technical improvement is required before APT imaging can be clinically applied to liver MRI., Key Points: • Liver APT imaging was technically feasible, but with a relatively low success rate (62.1%). • Liver metastases showed higher APT values than hepatocellular carcinomas.

Background & Aims: Despite the clinical and genetic significance of macrotrabecular-massive hepatocellular carcinoma (MTM-HCC), its characteristics on imaging have not been described. This study aimed to characterise MTM-HCC on gadoxetic acid-enhanced MRI and to evaluate the diagnostic accuracy and prognostic value of these imaging characteristics., Methods: We enrolled 3 independent cohorts from 2 tertiary care centres. The 3 cohorts consisted of a total of 476 patients who underwent gadoxetic acid-enhanced MRI and surgical resection for treatment-naïve single HCCs. Independent review of histopathology and MRI by 2 reviewers was performed for each cohort, and inter-reader agreement was evaluated. Based on the result of MRI review in the training cohort (cohort 1), we developed 2 diagnostic criteria for MTM-HCC and evaluated their prognostic significance. The diagnostic performance and prognostic significance were validated in 2 validation cohorts (cohorts 2 and 3)., Results: We developed 2 diagnostic MRI criteria (MRIC) for MTM-HCC: MRIC-1, ≥20% arterial phase hypovascular component; MRIC-2, ≥50% hypovascular component and 2 or more ancillary findings (intratumoural artery, arterial phase peritumoural enhancement, and non-smooth tumour margin). MRIC-1 showed high sensitivity and negative predictive value (88% and 95% in the training cohort, and 88% and 97% in the pooled validation cohorts, respectively), whereas MRIC-2 demonstrated moderate sensitivity and high specificity (47% and 94% in the training cohort, and 46% and 96% in the pooled validation cohorts, respectively). MRIC-2 was an independent poor prognostic factor for overall survival in both training and pooled validation cohorts., Conclusions: Using gadoxetic acid-enhanced MRI findings, including an arterial phase hypovascular component, we could stratify the probability of MTM-HCC and non-invasively obtain prognostic information., Lay Summary: Macrotrabecular-massive hepatocellular carcinoma (MTM-HCC) is a histopathologic subtype of HCC characterised by aggressive biological behaviour and poor prognosis. We developed imaging criteria based on liver MRI that could be used for the non-invasive diagnosis of MTM-HCC. HCCs showing imaging findings of MTM-HCC were associated with poor outcomes after hepatic resection., Competing Interests: Conflict of interests The authors declare no conflicts of interest that pertain to this work. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2020 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

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

Background/aims: The Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and modified RECIST (mRECIST) criteria have been used to assess treatment responses for hepatocellular carcinoma (HCC) patients. We investigated which criteria provides better survival predictions in HCC patients treated with transarterial radioembolization (TARE)., Methods: In total, 102 patients with unresectable intrahepatic HCC, who were treated with TARE between 2012 and 2017, were reviewed retrospectively. The treatment response after TARE was evaluated at 1, 3, and 6 months by the mRECIST and RECIST 1.1. Responders were defined as patients with complete or partial responses by each criterion., Results: The median age of 83 men and 19 women was 64.3 years. The median alpha-fetoprotein and des-gamma-carboxy prothrombin levels were 37.1 ng/mL and 1,780.0 mAU/mL, respectively. The median maximal tumor size was 8.3 cm, and multiple tumors were observed in 36 patients (35.3%). During the follow-up period (median, 20.7 months), 21 patients (20.6%) died, with a mean survival time of 55.5 months. The cumulative survival rate was 96.1% at 6 months and 89.3% at 12 months. Responders, defined by the mRECIST at 1, 3, and 6 months after TARE, showed better survival outcomes than nonresponders (hazard ratio [HR]=5.736, p=0.008 at 1 month; HR=3.145, p=0.022 at 3 months, and HR=2.887, p=0.061 at 6 months). The survival rates of responders and nonresponders defined by the RECIST 1.1 were similar (all p>0.05)., Conclusions: Response evaluations that use the mRECIST provide more accurate prognoses than those that use the RECIST 1.1 in HCC patients treated with TARE.

Background & Aims: Contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing CEUS at high risk for hepatocellular carcinoma (HCC). We performed a meta-analysis to determine the diagnostic performance of the CEUS LR-5 for HCC and the pooled proportions of HCCs in each CEUS LI-RADS category., Methods: We searched multiple databases for studies reporting the diagnostic accuracy of the CEUS LI-RADS. Random-effects model was used to determine summary estimates of the diagnostic performance of CEUS LR-5 and the pooled proportions of HCCs in each CEUS LI-RADS category. Risk of bias and concerns regarding applicability were evaluated with the Quality Assessment of Diagnostic Accuracy Studies-2 tool., Results: Eleven studies were included in the final analysis, which consisted of 5535 observations with 3983 HCCs. The pooled per-observation sensitivity and specificity of the CEUS LR-5 for diagnosing HCC were 69% (95% confidence interval [CI], 64%-73%) and 92% (95% CI, 83%-96%) respectively. The pooled proportions of HCCs were 0% (95% CI, 0-0%) for LR-1, 1% (95% CI, 0%-4%) for CEUS LR-2, 26% (95% CI, 14%-39%) for CEUS LR-3, 77% (95% CI, 68%-86%) for CEUS LR-4, 97% (95% CI, 95%-98%) for CEUS LR-5, 57% (95% CI, 44%-69%) for CEUS LR-M and 100% (95% CI, 93%-100%) for CEUS LR-5V or TIV., Conclusions: The CEUS LR-5 category showed moderate sensitivity and high specificity for diagnosing HCC. The proportion of HCCs was higher in the higher CEUS LI-RADS categories., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: The aim of this study was to determine the diagnostic performance of the LR-5 category for hepatocellular carcinoma (HCC) and the pooled proportion of HCC in each Liver Imaging Reporting and Data System (LI-RADS) category with CT and MRI, using LI-RADS version 2018., Methods: The MEDLINE, Embase, and Scopus databases were searched from inception to December 7, 2019, for studies reporting the diagnostic accuracy of LI-RADS version 2018 for HCC. Risk for bias and concerns regarding applicability were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Random-effects models were used to determine the summary estimates of the diagnostic performance of LR-5 and the pooled proportion of HCC for each LI-RADS category., Results: Fourteen studies were included in the final analysis, consisting of 2,708 observations with 1,841 HCCs. The pooled per-observation sensitivity and specificity of the LR-5 category for diagnosing HCC were 70% (95% confidence interval [CI], 61%-78%) and 91% (95% CI, 89%-93%), respectively. No HCCs were reported for LR-1 and LR-2. The pooled proportions of HCC were 31% (95% CI, 12%-50%) for LR-3, 64% (95% CI, 47%-80%) for LR-4, 95% (95% CI, 93%-96%) for LR-5, 54% (95% CI, 30%-77%) for LR-TIV, and 33% (95% CI, 21%-46%) for LR-M. The proportions of HCC were significantly different among the LI-RADS categories (P = .022)., Conclusions: The LR-5 category of LI-RADS version 2018 provided moderate sensitivity and high specificity for diagnosing HCC. Higher LI-RADS categories from LR-3 to LR-5 included greater proportions of HCC., (Copyright © 2020 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate if size measurements of liver observations is more variable in the arterial phase as suggested by LI-RADS and assess potential higher instability in categorization in this particular phase. Secondarily, to assess inter- and intra-reader agreement for size across phases., Materials and Methods: Patients with liver cirrhosis who underwent multi-arterial phase MRI between 2017 and 2018 were retrospectively selected. Three radiologists measured liver observations in each phase, independently, in a random order. Mean size between early and late arterial phases (AP), 2, 3 and 10 min delay and the number of observations crossing the LI-RADS size thresholds (10 and 20 mm) per phase were compared using McNemar's test. Reader agreement was evaluated using intraclass correlation coefficient (ICC) and bootstrap-based comparisons. Bonferroni's correction was applied to pairwise comparisons., Results: 94 observations (LR-3, LR-4, LR-5, and LR-M) were included. Mean sizes (mm) were late AP: 19.9 (95% CI 17.2, 24.2), 2 min delay: 19.8 (95% CI 17.1, 24.0), 3 min delay: 19.8 (95% CI 17.2, 24.0), 10 min delay: 20.2 (95% CI 17.5, 24.5) (p = 0.10-0.88). There was no difference between phases in number of observations that could have changed category due to variability in size (p = 0.546-1.000). Inter- and intra-reader agreement was excellent (ICC = 0.952-0.981)., Conclusion: Measurements of focal liver observations were consistent across all post-contrast imaging phases and we found no higher instability in LI-RADS category in any particular phase. Inter- and intra-reader agreement for size was excellent for each phase. Based on these findings, size measurement could be allowed on any post-contrast phase, including the arterial phase, if deemed appropriate by the radiologist.

Background MRI with hepatobiliary contrast material is more sensitive than MRI with extracellular contrast material in the detection of hepatocellular carcinoma (HCC). Purpose To determine whether postsurgical outcomes differ between patients who undergo MRI with hepatobiliary contrast material and those who undergo MRI with extracellular contrast material by analyzing disease-free survival (DFS) rates after curative resection of HCC. Materials and Methods From January 2014 to December 2015, 170 treatment-naïve patients who underwent contrast-enhanced preoperative liver MRI and curative hepatic resection for HCC were retrospectively included and observed until September 2018. DFS rates were compared between the two groups, which were classified based on the type of MRI contrast agent used. The MRI with hepatobiliary contrast material group was further divided into a hypointense nodule-positive group and a hypointense nodule-negative group according to the presence of residual hepatobiliary phase (HBP) hypointense nodules without arterial phase hyperenhancement (APHE) after surgery. DFS rates were calculated by using the Kaplan-Meier method and were compared among the three groups by using a log-rank test. Results Patients were included in either the MRI with extracellular contrast material group ( n = 53; mean age, 60 years ± 9 [standard deviation]) or the hepatobiliary contrast material group ( n = 117; mean age, 60 years ± 8; 26 patients were in the hypointense nodule-positive group). Over a median follow-up period of 34.1 months, median DFS rates did not differ between the extracellular contrast material group (35.8 months) and the hepatobiliary contrast material group (43.5 months) ( P = .46). However, median DFS in the extracellular contrast material group was longer than that in the hypointense nodule-positive group (35.8 months vs 25.8 months, P < .001) and shorter than that in the hypointense nodule-negative group (35.8 months vs 48.6 months, P = .02). Conclusion Patients who undergo preoperative MRI with hepatobiliary contrast material and resection of hepatobiliary phase hypointense nodules without arterial phase hyperenhancement may show better disease-free survival. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Motosugi in this issue.

Objectives: The aim of this study was to compare the major imaging features of hepatocellular carcinoma (HCC) on magnetic resonance imaging (MRI) scans with Gd-EOB-DTPA (EOB) and extracellular agent (ECA; Gd-DTPA) contrast media., Materials and Methods: Among 184 surgically proven HCCs in 169 patients who underwent a liver MRI with either EOB (n = 120) or ECA (n = 49), 55 HCCs were matched according to tumor size, Edmonson grade (major and worst), and gross type for each of the 2 contrast media. For the qualitative analysis, 2 board-certified radiologists independently reviewed arterial phase hyperenhancement, hypointensity on portal venous phase, hypointensity on delayed or transitional phase (DP/TP, 120-150 seconds), and capsule appearance. For the quantitative analysis, a third radiologist measured the signal intensity at each phase by placing the region of interest for tumor and normal liver parenchyma. The lesion-to-liver contrast (LLC) and lesion-to-liver contrast enhancement ratio (LLCER) were calculated., Results: On qualitative analysis, hypointensity on DP/TP was seen more frequently with EOB (91% in reader 1, 89% in reader 2) than with ECA (73% in reader 1, 75% in reader 2; P = 0.026). Capsule appearance was seen less frequently with EOB (31% in reader 1, 44% in reader 2) than with ECA (73% in reader 1, 78% in reader 2; P < 0.001). On quantitative analysis, the LLC on arterial phase (AP) was better with ECA (P = 0.003), whereas LLC on DP was better with EOB (P < 0.001). The LLCER from precontrast to AP was higher with ECA (P = 0.022), whereas the LLCER from portal venous phase to DP was higher with EOB (P < 0.001)., Conclusions: ECA-MRI revealed better LLC on AP and detection rate of capsule appearance than EOB-MRI. EOB-MRI showed superior LLC on TP.

Purpose: The purpose of this study was to investigate the impact of contrast enhanced pancreatic magnetic resonance imaging (MRI) in resectability and prognosis evaluation after staging computed tomography (CT) in patients with pancreatic ductal adenocarcinoma (PDA)., Materials and Methods: From January 2005 to December 2012, 298 patients were diagnosed to have potentially resectable stage PDA on CT. Patients were divided into CT+MR (patients underwent both CT and MRI; n=216) and CT only groups (n=82). Changes in resectability staging in the CT+MR group were evaluated. The overall survival was compared between the two groups. The recurrence-free survival and median time to liver metastasis after curative surgery were compared between the two groups., Results: Staging was changed from resectable on CT to unresectable state on MRI in 14.4% of (31 of 216 patients) patients of the CT+MR group. The overall survival and recurrence-free survival rates were not significantly different between the two groups (p=0.162 and p=0.721, respectively). The median time to liver metastases after curative surgery in the CT+MR group (9.9 months) was significantly longer than that in the CT group (4.2 months) (p=0.011)., Conclusion: Additional MRI resulted in changes of resectability and treatment modifications in a significant proportion of patients who have potentially resectable state at CT and in prolonged time to liver metastases in patients after curative surgery. Additional MRI to standard staging CT can be recommended for surgical candidates of PDA.

Purpose: This study was conducted to compare the diagnostic performance and early recurrence rate between gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) and magnetic resonance imaging (MRI) with extracellular contrast agent (ECA-MRI) for evaluating hepatic lesions in colorectal cancer., Materials and Methods: Between 2005 and 2010, 418 colorectal cancer patients with both preoperative computed tomography (CT) and liver MRI were retrospectively reviewed. Image analysis was based on initial radiologic reports, and diagnostic performance was assessed based on the area under the receiver operating characteristic curve (AUROC). The early intrahepatic recurrence rate within 6 months was then evaluated., Results: Overall, 291 and 127 patients underwent Gd-EOB-MRI and ECA-MRI, respectively. The AUROCs were not significantly different between Gd-EOB-MRI (0.990; 95% CI, 0.980 to 0.999) and ECA-MRI (0.985; 95% CI, 0.968 to 1.000; p=0.836). When compared with CT alone, ECA-MRI detected additional 21 lesions in 14 patients (14/127, 11.0%), whereas Gd-EOB-MRI detected 56 lesions in 33 patients (33/291, 11.3%) without a significant difference between two MRI groups (p=0.331). The early recurrence rate in the ECA-MRI (28.6%) was significantly higher than that in the Gd-EOB-MRI (11.6%) for patients who underwent hepatic resection (p=0.031)., Conclusion: Gd-EOB-MRI is potentially better than ECA-MRI for decreasing the early intrahepatic recurrence rate, although the two MRI modalities showed comparable diagnostic performance in colorectal cancer patients.

Objective: The purpose of this study was to examine the associations between preoperative Liver Imaging Reporting and Data System (LI-RADS) categories and prognosis after curative resection of single hepatic malignancies in patients with chronic liver disease., Materials and Methods: Between January 2008 and December 2010, 225 patients with chronic liver disease underwent resection of single hepatic malignant tumors (218 hepatocellular carcinomas, three cholangiocarcinomas, four biphenotypic carcinomas) after undergoing gadoxetic acid-enhanced MRI. Two radiologists retrospectively categorized the tumors into LI-RADS categories. Differences in disease-free survival duration between categories were analyzed by the Kaplan-Meier method with the log-rank test., Results: Reviewer 1 categorized two (0.9%) patients as having LR-3, 53 (23.6%) LR-4, 159 (70.7%) LR-5, and 11 (4.9%) LR-M lesions. The corresponding numbers for reviewer 2 were six (2.7%) LR-3, 30 (13.3%) LR-4, 178 (79.1%) LR-5, and 11 (4.9%) LR-M. The 2-year cumulative recurrence or death rates were 15.1% for lesions categorized LR-3 or LR-4 by reviewer 1, 31.7% for LR-5, and 60% for LR-M. For lesions categorized by reviewer 2 the corresponding rates were 20.6% for LR-3 or LR-4, 29% for LR-5, and 54.5% for LR-M. Disease-free survival was significantly worse among patients with lesions categorized as LR-M than for lesions categorized as LR-3 or LR-4 or as LR-5 (p < 0.01 for both reviewers). Disease-free survival did not significantly differ between patients with LR-3 or LR-4 and those with LR-5 lesions (reviewer 1, p = 0.301; reviewer 2, p = 0.291)., Conclusion: Patients with tumors preoperatively categorized as LR-M may have a worse prognosis than those with tumors categorized LR-3, LR-4, or LR-5 after curative resection of single hepatic malignancy.

Objective: To evaluate the feasibility of angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular liver tumors abutting abdominal wall, in order to traverse normal liver parenchyma, and thereby, obtain favorable configuration of ablation margin., Materials and Methods: In this study, we retrospectively analyzed 15 small superficial subcapsular liver tumors abutting abdominal wall in 15 patients, treated with radiofrequency ablation from March 2013 to June 2015 using a cool-tip electrode manually modified to create 25-35° angle at the junction between exposed and insulated segments. The tumors were hepatocellular carcinoma (n = 13) and metastases (n = 2: cholangiocellular carcinoma and rectosigmoid cancer), with maximum diameter of 10-26 mm (mean, 15.68 ± 5.29 mm). Under ultrasonographic guidance, the electrode tip was advanced to the depth of the tumors' epicenter about 1 cm from the margin. The tip was re-directed to penetrate the tumor for radiofrequency ablation. Minimal ablation margin was measured at immediate post-treatment CT. Radiological images and medical records were evaluated for success rate, length of minimal ablation margin and complications., Results: Technical success rate of obtaining complete necrosis of the tumors was 100%, with no procedure-related complication. Minimal ablation margin ranged from 3-12 mm (mean, 7.07 ± 2.23 mm). CT/MRI follow-up at 21-1022 days (mean, 519.47 ± 304.51 days) revealed no local recurrence, but distant recurrence in 9 patients., Conclusion: Using an angled cool-tip electrode for radiofrequency ablation of small superficial subcapsular tumors abutting abdominal wall may be a feasible technique for obtaining adequate ablation margin and lower complication rate.

Purpose: To identify magnetic resonance (MR) imaging features that enable prediction of early recurrence (<2 years) after curative resection of hepatocellular carcinoma (HCC) and to derive a preoperative prediction model., Materials and Methods: This retrospective study was approved by the institutional review board. The requirement to obtain written informed consent was waived. A total of 268 patients who underwent hepatic resection for a single HCC from January 2008 to August 2011 were divided into two cohorts: a training cohort, which was used to derive a prediction model (n = 187), and a validation cohort (n = 81). All MR images from the training cohort were reviewed by two radiologists. A prediction model was constructed by using MR imaging features that were independently associated with early recurrence with use of multiple logistic regression analysis. The performance of the prediction model in the validation cohort was evaluated with respect to discrimination (ie, whether the relative ranking of individual predictions of subsequent early recurrence is in the correct order)., Results: In the training cohort, four MR imaging features were independently associated with early recurrence: rim enhancement (odds ratio [OR] = 3.83; 95% confidence interval [CI]: 1.39, 10.52), peritumoral parenchymal enhancement in the arterial phase (OR = 2.64; 95% CI: 1.27, 5.46), satellite nodule (OR = 4.07; 95% CI: 1.09, 15.21), and tumor size (OR = 1.66; 95% CI: 1.31, 2.09). A prediction model derived from these variables showed an area under the receiver operating characteristic curve (AUC) of 0.788 in the prediction of the risk of early recurrence in the training cohort. When applied to the validation cohort, this model showed good discrimination (AUC, 0.783)., Conclusion: The prediction model derived from rim enhancement, peritumoral parenchymal enhancement, satellite nodule, and tumor size can be used preoperatively to estimate the risk of early recurrence after resection of a single HCC., ((©) RSNA, 2015 Online supplemental material is available for this article.)

Objective: To evaluate the appropriateness of follow-up with only non-enhanced CT (NECT) in patients with gastrointestinal cancer., Subjects and Methods: This retrospective study included 323 patients with colorectal and gastric cancer who underwent two consecutive CT examinations (CT1 and CT2), including non-contrast and portal venous phase CT images, with an interval of 1 year. Patients were divided into 2 groups: Group A included patients with no hepatic metastasis on CT1 and with or without newly developed metastasis on CT2 to evaluate the diagnostic performance of NECT for detecting newly developed hepatic metastasis; Group B included patients with known hepatic metastasis both on CT1 and CT2 to evaluate the accuracy of NECT for the assessment of hepatic metastasis based on RECIST criteria (version 1.1). Contrast-enhanced CT (CECT) images were considered as reference standards., Results: Group A included 172 patients (M:F = 107:65; mean age, 62.6 years). Among them, 57 patients had 95 metastases (mean size, 2.2 ± 1.3 cm). Per patient and per lesion sensitivity for diagnosing newly developed hepatic metastasis was 56.1-66.7% and 52.6-56.8%, respectively. In terms of small metastases (<1.5 cm), per lesion sensitivity was significantly decreased to 28.1-34.4% (P < 0.05). Metastasis size measurements were significantly smaller on NECT (P < 0.001) compared with reference standards. In Group B, the accuracy of response evaluation based on RECIST criteria was 65.6-72.2%., Conclusions: NECT showed inadequate diagnostic performances in both detecting newly developed hepatic metastasis and evaluating the response of hepatic metastasis based on RECIST criteria.

Backgrounds & Aims: The aim of this study is to evaluate the prognostic significances of not only the initial and the best response during repeated transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC), but if eligible, also the time point of achieving treatment responses., Methods: Three hundred and fourteen treatment-naïve patients with well-preserved liver function undergoing TACE were recruited. Treatment responses were assessed using modified Response Evaluation Criteria in Solid Tumors. Overall survival (OS) was analyzed using Kaplan-Meier methods, and Cox regression analysis was performed for multivariate analysis., Results: After adjusting other variables, objective response (complete response [CR] and partial response [PR]) as the initial response (adjusted hazard ratio [HR] 0.410) and the best response (adjusted HR 0.335) had independent prognostic significances for OS, respectively (both p < 0.001). Objective responders as the initial response had the longest OS, followed by patients who subsequently achieved objective response after at least two sessions and those who did not achieve objective response during treatment course eventually (52.6, 27.0, and 10.8 months, respectively; log-rank test, p < 0.001). Likewise, patients with CR as the initial response had the longest OS, followed by those who subsequently achieved CR after at least two sessions and those who achieved PR as the best response (70.2, 40.6, and 23.0 months, respectively; log-rank test, p < 0.001). Large (>5 cm) and multiple (⩾ 4) tumors were independently associated with failure to achieve CR after the initial TACE (both p < 0.05)., Conclusion: Both the initial and the best response predicts OS effectively. However, achievement of treatment response at an early time point is still the most robust predictor for favorable outcomes., (Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Objective: To assess the added value of arterial enhancement fraction (AEF) color maps for the differentiation of small metastases from hepatic benign lesions., Subjects and Methods: We retrospectively analyzed 46 patients with colorectal cancer who underwent multiphasic liver CT imaging and had low-attenuating liver lesions smaller than 3 cm (123 total lesions; metastasis: benign = 32:91). AEF color maps of the liver were created from multiphasic liver CT images using dedicated software. Two radiologists independently reviewed multiphasic CT image sets alone and in combination with image sets with AEF color maps using a five-point scale. The additional diagnostic value of the color maps was assessed by means of receiver-operating characteristic (ROC) analysis., Results: The area under the ROC curve (Az) increased when multiphasic CT images were combined with AEF color map analysis as compared with evaluation based only on multiphasic CT images (from 0.698 to 0.897 for reader 1, and from 0.825 to 0.945 for reader 2; P < 0.001 and 0.002, respectively). The increase Az was especially significant for lesions less than 1 cm (from 0.702 to 0.888 for reader 1, and from 0.768 to 0.958 for reader 2; P = 0.001 and P = 0.001, respectively). The mean AEF of tumor-adjacent parenchyma (35.07 ± 27.2) was significantly higher than that of tumor-free liver parenchyma (27.3 ± 20.6) (P = 0.04)., Conclusions: AEF color mapping can improve the diagnostic performance for small hepatic metastases from colorectal cancer and may allow for the elimination of additional examinations.

Background & Aims: The dynamic enhancement pattern of HCCs smaller than 3 cm in diameter on gadoxetic acid-enhanced magnetic resonance imaging (MRI) have not been extensively investigated. We aimed to evaluate the dynamic enhancement patterns of small HCCs (≤3 cm) on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and compare enhancement patterns with multiphasic multidetector computed tomography (MDCT) based on tumour cellular differentiation and size., Methods: We retrospectively included 55 patients with 67 surgically confirmed small HCCs (≤3 cm) who underwent multiphasic MDCT and gadoxetic acid-enhanced MRI. Dynamic enhancement patterns were analysed according to tumour cellular differentiation and size. Hepatobiliary phase images were also analysed to assess their additional value., Results: The proportion of small HCCs demonstrating the typical enhancement pattern differed depending on tumour cellular differentiation on both MRI (P = 0.001) and MDCT (P = 0.001), but differed depending on tumour size only on CT (P = 0.008). Gadoxetic acid-enhanced MRI more sensitively depicted the typical enhancement pattern than CT for all tumours (P = 0.001), for moderately or poorly differentiated HCCs (P = 0.021) and for HCCs ≤2 cm (P = 0.001). 80% of tumours with atypical enhancement could be diagnosed as HCC based on tumour size and hepatobiliary phase images., Conclusions: On both gadoxetic acid-enhanced MRI and multiphasic CT, the dynamic enhancement patterns of small HCCs (≤3 cm) differed according to tumour cellular differentiation. Gadoxetic acid-enhanced MRI more frequently demonstrated the typical HCC enhancement pattern than CT in small HCCs., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The objectives of the study were to evaluate the image quality and diagnostic performance of sinogram-affirmed iterative reconstruction (SAFIRE) for detecting hepatic metastasis and to estimate the potential radiation dose reduction at abdominal computed tomography (CT)., Materials and Methods: Fifty-nine consecutive patients (mean age, 59.2 years; range, 42-81 years) who had hepatic metastasis and who underwent dual-source abdominal CT were enrolled in this study. The image noise of the liver was compared between full-dose filtered back projection images (FD-FBP) and simulated half-dose images, which used only single-source projection data, and reconstructed with different strengths of SAFIRE (HD-SAFIRE(1-5)) by 1-way analysis of variance with Bonferroni correction. The diagnostic performance for hepatic metastasis was compared by logistic regression with the weighted least squares method and noninferiority test between the FD-FBP images and the half-dose sinogram-affirmed iterative reconstruction (HD-SAFIRE) images., Results: As the SAFIRE strength increased, image noise decreased (P < 0.001). The images of HD-SAFIRE(2) showed similar image noise for liver parenchyma (13.4 Hounsfield unit [HU]), signal-to-noise ratio for liver parenchyma (9.2), and lesion-to-liver contrast-to-noise ratio (4.5), compared with the FD-FBP images (12.6 HU, P = 0.668; 9.6, P > 0.999; and 4.5, P > 0.999, respectively). The diagnostic accuracy for hepatic metastasis with the HD-SAFIRE(2) images (87.5%) was not different from that of the FD-FBP images (87.5%, P > 0.999). The diagnostic performance of the HD-SAFIRE(2) images was also noninferior to that of the FD-FBP images (95% confidence interval lower limit difference [-9.16%] excluding the -10% clinical noninferiority limit). The mean (SD) volume CT dose index of FD-FBP was 11.26 (2.66) mGy, and the mean (SD) radiation dose equivalent associated with HD-SAFIRE was estimated to be 5.63 (1.33) mGy., Conclusions: By applying SAFIRE2, the radiation dose could be reduced by up to 50% compared with the standard-of-care abdominal CT protocol without increasing image noise and without deteriorating diagnostic performance for the detection of hepatic metastasis.

Objective: To compare the accuracy of multidetector computed tomography (MDCT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) for the detection of intrahepatic tumor recurrence after curative resection of hepatocellular carcinoma (HCC)., Materials and Methods: Fifty-six patients who underwent MDCT and gadoxetic acid-enhanced MRI for postoperative surveillance after resection of HCC were retrospectively analyzed; 26 patients had a recurrence (36 lesions) and 30 patients did not. Recurrent HCCs were confirmed by histological examinations in two, typical dynamic imaging findings on CT and/or MRI in 28, and by demonstration of growth or tumor staining on angiography on six. Two reviewers graded the confidence for the presence of recurrence on CT and MRI, using a five-point scale. The jackknife free-response receiver operating characteristic method was used to compare diagnostic performance. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated., Results: For 36 recurrent lesions, the figure of merit was significantly higher for MRI than MDCT for detecting recurrence for both reviewers (p < 0.005 for both reviewers). In lesion-by-lesion analysis, the sensitivity was significantly higher on MRI (100% for reviewer 1 and 97% for reviewer 2) than on MDCT (44.4% and 66.6%) for both reviewers (p < 0.005 for both reviewers). Also in patient-by-patient analysis, sensitivity was significantly higher on MRI (100% and 96.1%) than on MDCT (57.6% and 76.9%) for both reviewers (p < 0.05 for both reviewers)., Conclusion: Gadoxetic acid-enhanced MRI is superior to MDCT for detecting intrahepatic recurrence after curative resection of HCC.

As a result of recent developments in imaging modalities and wide spread routine medical checkups and screening, more incidental liver lesions are found frequently on US these days. When incidental liver lesions are found on US, physicians have to make a decision whether to just follow up or to undergo additional imaging studies for lesion characterization. In order to choose the next appropriate imaging modality, the diagnostic accuracy of each imaging study needs to be considered. Therefore, we tried to compare the accuracy of contrast-enhanced multidetector CT (MDCT) and Gd-EOB-DTPA-enhanced MRI for characterization of incidental liver masses. We included 127 incidentally found focal liver lesions (94 benign and 33 malignant) from 80 patients (M∶F = 45∶35) without primary extrahepatic malignancy or chronic liver disease. Two radiologists independently reviewed Gd-EOB-DTPA-enhanced MRI and MDCT. The proportion of confident interpretations for differentiation of benign and malignant lesions and for the specific diagnosis of diseases were compared. The proportion of confident interpretations for the differentiation of benign and malignant lesions was significantly higher with EOB-MRI(94.5%-97.6%) than with MDCT (74.0%-92.9%). In terms of specific diagnosis, sensitivity and accuracy were significantly higher with EOB-MRI than with MDCT for the diagnosis of focal nodular hyperplasia (FNH) and focal eosinophilic infiltration. The diagnoses of the remaining diseases were comparable between EOB-MRI and MDCT. Hence, our results suggested that Gd-EOB-MRI may provide a higher proportion of confident interpretations than MDCT, especially for the diagnosis of incidentally found FNH and focal eosinophilic infiltration.

Purpose: To define the histological characteristics of hepatocellular carcinomas (HCCs) showing atypical dynamic enhancement patterns on gadoxetic acid-enhanced dynamic magnetic resonance imaging (EOB-MRI)., Materials and Methods: We evaluated a total of 130 small (≤ 3 cm) HCCs from 114 patients that were surgically removed after EOB-MRI. Two radiologists blinded to the histological findings retrospectively classified the HCCs into typical or atypical lesions. Gross morphology, nuclear histological grade, presence of vascular invasion, and capsule formation and infiltration were compared between the two groups using Chi-square or Fisher tests., Results: Atypical dynamic enhancement patterns were seen in 23 HCCs (17.7%). None of the atypical HCC showed vascular invasion (P < 0.001). Atypical HCCs also showed more frequently smaller size (1.6 ± 0.6 cm versus 2.1 ± 0.6 cm, P = 0.001) with 86.9% (n = 20) of which 2 cm or less in diameter (P = 0.001), vaguely nodular appearance (56.5% vs 3.7%, P < 0.001), and nuclear grade I (69.6% versus 6.5%, P < 0.001), while less frequently showed capsule formation (26.1% versus 77.6%, P < 0.001) or capsular infiltration (16.7% versus 77.1%, P = 0.005)., Conclusion: Atypical HCCs on EOB-MRI may be characterized by the absence of vascular invasion, smaller (< 2 cm or less) size, vaguely nodular appearance, and well differentiation, and infrequent capsule formation or capsular infiltration., (Copyright © 2012 Wiley Periodicals, Inc.)

Objective: The purpose of our study was to assess the relationship between time intervals of CT examinations and the stages of hepatocellular carcinomas (HCCs) detected during the surveillance of patients with liver cirrhosis., Materials and Methods: In this study, 73 patients with 93 HCCs (reference standard: surgery, n=7 [8 HCCs]; biopsy, n=2 [3 HCCs]; imaging criteria, n=64 [82 HCCs]) who showed no evidence of HCC on prior CT examinations were included. Patients were stratified into three groups based on the time interval between the two CT examinations: groups A (interval≤1 year, n=21), B (interval between 1 and 2 years, n=25), and C (interval≥2 years, n=27). Tumor stages according to the American Joint Committee on Cancer (AJCC), the Barcelona Clinic Liver Cancer (BCLC) staging system, and the Milan criteria were evaluated retrospectively by two reviewers. The Fisher exact test was used to compare tumor stages. Spearman correlation coefficients were used to assess the correlation between the CT interval and tumor size., Results: One (4%) HCC in group B and four (15%) HCCs in group C were larger than 5 cm in diameter, whereas no tumor was larger than 3 cm in diameter in group A. There was no difference in tumor diameter between groups, but tumor size was positively correlated with time interval between examinations (Spearman correlation coefficient, 0.472; p<0.001). In group A, 19 (90%) patients had cancers categorized as T1, and the remaining patients had cancers categorized as T2. In group B, one (4%) patient had a cancer that was categorized as T3b according to the AJCC classification, in the intermediate stage according to the BCLC classification, and above the Milan criteria. In group C, three (11%) patients had T3b cancers, and five had cancers in either intermediate or higher stage and above the Milan criteria., Conclusion: HCC detected on CT performed within 1 year of a negative examination was at a curable stage in patients with liver cirrhosis.

Objective: The aim of this study was to determine the registration error of an ultrasound (US) fusion imaging system during an ex vivo study and its clinical value for percutaneous radiofrequency ablation (pRFA) during an in vivo study., Materials and Methods: An ex vivo study was performed using 4 bovine livers and 66 sonographically invisible lead pellets. Real-time CT-US fusion imaging was applied to assist the targeting of pellets with needles in each liver; the 4 sessions were performed by either an experienced radiologist (R1, 3 sessions) or an inexperienced resident (R2, 1 session). The distance between the pellet target and needle was measured. An in vivo study was retrospectively performed with 51 nodules (42 HCCs and 9 metastases; mean diameter, 16 mm) of 37 patients. Fusion imaging was used to create a sufficient safety margin (>5 mm) during pRFA in 24 nodules (group 1), accurately target 21 nodules obscured in the US images (group 2) and precisely identify 6 nodules surrounded by similar looking nodules (group 3). Image fusion was achieved using MR and CT images in 16 and 21 patients, respectively. The reablation rate, 1-year local recurrence rate and complications were assessed., Results: In the ex vivo study, the mean target-needle distances were 2.7 mm±1.9 mm (R1) and 3.1±3.3 mm (R2) (p>0.05). In the in vivo study, the reablation rates in groups 1-3 were 13%, 19% and 0%, respectively. At 1 year, the local recurrence rate was 11.8% (6/51). In our assessment of complications, one bile duct injury was observed., Conclusion: US fusion imaging system has an acceptable registration error and can be an efficacious tool for overcoming the major limitations of US-guided pRFA., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objectives: To investigate the effectiveness of qualitative diffusion-weighted imaging (DWI), subtraction of unenhanced from arterial phase images, and hepatobiliary phase (HBP) images in estimating the histopathological grade of hepatocellular carcinoma (HCC)., Methods: We retrospectively reviewed gadoxetic acid-enhanced magnetic resonance images of 175 patients with 201 surgically resected HCCs. The signal intensity and its relationship with histopathological grade were assessed for each sequence and a combination of sequences., Results: There was a tendency towards higher grades in tumours showing restricted diffusion on DWI (P < 0.001) or arterial enhancement on subtraction imaging (P < 0.001), but not hepatocyte-defect on HBP images (P = 0.33). When lesions were divided into three groups based on combined findings on DWI and subtraction imaging, a linear trend was observed between group and grade (P < 0.001). The positive predictive value (PPV) of the combination of no restricted diffusion and no arterial enhancement in predicting well-differentiated HCC was 100%, higher than the PPV of individual findings on DWI (74%) or subtraction imaging (81%)., Conclusions: DWI and subtraction imaging are helpful for predicting the histopathological grade of HCC, especially when the two sequences are considered together., Key Points: • Predicting the histopathological grade of hepatocellular carcinoma (HCC) preoperatively is important. • Diffusion-weighted imaging (DWI) and subtraction imaging are recently developed MR techniques. • Retrospective study showed DWI and subtraction imaging helps predict HCC grades. • Management of patients with HCC becomes more appropriate.

Background: To evaluate hepatocellular carcinoma (HCC) that developed in patients with no evidence of a tumor during a prior ultrasound (US) performed within 1 year of the diagnosis., Methods: We retrospectively analyzed data for 100 consecutive patients with liver cirrhosis who had undergone US within 1 year prior to HCC diagnosis and who showed no liver lesions on the previous US. Size and T stage of HCC were assessed as well as whether patients met surgical criteria for liver transplantation as HCC treatment [Milan or University of California at San Francisco (UCSF) criteria]., Results: The mean interval between the negative and diagnostic scans was 5 months, 13 days. HCC presented as a single nodule in 69 patients (size, 0.8-8.0 cm), as two or more nodules in 18 patients, and as the diffuse form of HCC in 13 patients. HCC presented as a small tumor (<3 cm) in 48 patients. T stages were: T1 in 26 patients, T2 in 45, T3 in 18, and T4 in 11. The Milan criteria were met in 79 patients. Eighty-five patients fulfilled the UCSF., Conclusion: Patients may present with advanced HCC, even if sonographic findings were negative within 1 year prior to diagnosis., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objective: To assess whether reticular hypointensity on hepatobiliary phase images of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) is a diagnostic finding of sinusoidal obstruction syndrome (SOS) in patients with hepatic metastases who have undergone chemotherapy., Methods: We retrospectively analysed EOB-MRI of 42 patients who had undergone chemotherapy before hepatic resection of colorectal hepatic metastases. Two radiologists, who were unaware of whether or not the patients had SOS, reviewed the hepatobiliary phase images to determine the presence of hypointense reticulation in the liver using a 5-point scale. The sensitivity, specificity and area under the receiver operating characteristics curve (A(z)) were calculated for each reviewer., Results: The sensitivity, specificity and A(z) for the diagnosis of SOS were 75%, 100% and 0.957 for reader 1 and 75%, 96.2% and 0.936 for reader 2, respectively. In one patient who received a false-positive diagnosis by one reader, there was sinusoidal fibrosis on histological examination, but not diagnostic for SOS. False-negative diagnosis occurred in four patients for both readers; histology of these patients showed minimal and localised sinusoidal congestion and fibrosis., Conclusions: Reticular hypointensity on hepatobiliary phase images of EOB-MRI is highly specific for the diagnosis of SOS in patients with treated colorectal hepatic metastases., Key Points: Gadoxetic acid enhanced magnetic resonance imaging (EOB-MRI) can identify the sinusoidal obstruction syndrome (SOS). The diagnosis can be achieved with high specificity and good interobserver agreement. SOS typically demonstrates diffuse hypointensity on hepatobiliary phase images on EOB-MRI. EOB-MRI may be falsely negative in patients with minimal degree of SOS.

Purpose: To retrospectively compare the diagnostic accuracy for the detection of colorectal liver metastases between gadoxetic acid-enhanced MRI (EOB-MRI) and diffusion-weighted imaging (DWI) on 3.0 Tesla (T) system, and then to determine whether a combination of the two techniques may improve the diagnostic performance., Materials and Methods: Forty-seven patients underwent MR imaging at 3.0T, including DWI (DWI set) and dynamic and hepatobiliary phase EOB-MRI (EOB set) for the preoperative evaluation of colorectal liver metastases. All suspicious metastases were confirmed by hepatic surgery. Two blinded readers independently reviewed three different image sets, which consisted of DWI set, EOB set, and combined set. The accuracy was assessed by the area (Az) under the alternative-free response receiver operating characteristic curve, and the sensitivity and positive predictive value (PPV) were calculated., Results: We found a total of 78 confirmed colorectal liver metastases in 42 of 47 patients. Each reader noted higher diagnostic accuracy of combined set of EOB-MRI and DWI than DWI set and EOB set, without statistical significance. Regardless of the size of colorectal liver metastasis, each reader detected significantly more metastases on combined set than on DWI set, and PPV was significantly higher with DWI set than with EOB set or with combined set for one reader., Conclusion: EOB-MRI was more useful for the detection of colorectal liver metastases, while DWI was more useful for their characterization. The combination of EOB-MRI and DWI showed significantly higher accuracy and sensitivity for the preoperative detection of small colorectal liver metastases than DWI., (Copyright © 2011 Wiley-Liss, Inc.)

Objective: To retrospectively assess the value of adding gadolinium-enhanced dynamic imaging to standard ununenhanced magnetic resonance imaging (MRI) for characterising hypoattenuating hepatic lesions that are too small to characterise with multi-detector computed tomography (MDCT)., Methods: Informed consent was waved, and institutional review board approval was obtained. Three hundred and forty-six small (≤ 2 cm) lesions (63 metastatic, 283 benign) in 183 patients with underlying carcinoma who underwent hepatic MRI after CT were retrospectively analysed. Two radiologists independently reviewed images and diagnoses were graded on an ordinal scale from 1 (definitely benign) to 5 (definitely malignant). Receiver operating characteristic analysis was used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were also determined., Results: The areas under the curve of the ununenhanced images alone and with dynamic images were 0.837 and 0.850 for reader 1 (p = 0.616) and 0.771 and 0.783 for reader 2 (p = 0.700). Descriptive statistical values demonstrated sensitivities of 76% and 80%, specificities of 93% and 95%, PPVs of 69% and 79%, NPVs of 95% and 95% and accuracies of 90% and 92%, respectively., Conclusion: The value of adding three-phase contrast-enhanced MRI to unenhanced imaging did not reach statistical significance for characterising small hypoattenuating hepatic lesions on MDCT.

Purpose: To determine the added value of hepatobiliary phase images in gadoxetic acid-enhanced magnetic resonance (MR) imaging in the evaluation of hepatocellular carcinoma (HCC)., Materials and Methods: Institutional review board approved this retrospective study and waived the informed consent. Fifty-nine patients with 84 HCCs underwent gadoxetic acid-enhanced MR examinations that included 20-minute delayed hepatobiliary phase imaging. MR imaging was performed with a 1.5-T system in 19 patients and a 3.0-T system in 40 patients. A total of 113 hepatic nodules were documented for analysis. Three radiologists independently reviewed two sets of MR images: set 1, unenhanced (T1- and T2-weighted) and gadoxetic acid-enhanced dynamic images; set 2, hepatobiliary phase images and unenhanced and gadoxetic acid-enhanced dynamic images. For each observer, the diagnostic accuracy was compared by using the area under the alternative free-response receiver operating characteristic curve (A(z)). Sensitivity and specificity were also calculated and compared between the two sets., Results: For all observers, A(z) values were higher with the addition of the hepatobiliary phase. The observer who had the least experience in abdominal imaging (2 years) demonstrated significant improvement in A(z), from 0.895 in set 1 to 0.951 in set 2 (P = .049). Sensitivity increased with the addition of hepatobiliary phase images but did not reach statistical significance. Nine HCCs (10.7%) in six patients (10.1%) were seen only on hepatobiliary phase images., Conclusion: Hepatobiliary phase images obtained after gadoxetic acid-enhanced dynamic MR imaging may improve diagnosis of HCC and assist in surgical planning.

Purpose: To assess the diagnostic performance of gadobenate dimeglumine-enhanced 3D gradient echo (3D-GRE) magnetic resonance imaging (MRI) for the detection of hepatic hypovascular metastases., Materials and Methods: We retrospectively analyzed the initial radiologic reports of MRI of 41 patients with suspected hepatic metastases. Seventy-nine metastatic lesions were confirmed by histopathology or intraoperative ultrasound (IOUS). The sensitivity and positive predictive values for the diagnosis of hepatic metastasis were determined among each MRI set (hepatobiliary phase, precontrast images, dynamic imaging). The diagnostic performance of dynamic image set and combined dynamic and hepatobiliary image set was also evaluated by two radiologists using alternative free response receiver operating characteristic (ROC) analysis., Results: The overall detection rate and positive predictive value of MR were 96.2% (76/79) and 96.2% (76/79), respectively. Images obtained with hepatobiliary phase 3D-GRE showed a significantly better detection rate compared to those with precontrast sequences or dynamic imaging (P = 0.008 and 0.016, respectively). Regarding lesions 1 cm or smaller, the detection rate was 90.3% (28/31). Each reader showed a higher Az value of the combined hepatobiliary image set than those of the dynamic image set., Conclusion: 3D-GRE MRI using a hepatobiliary contrast agent is an accurate tool in the detection of hepatic hypovascular metastases and improves detection rate compared with precontrast and dynamic imaging.

Objective: The purpose of this article is to show the imaging findings of variant types of hepatocellular carcinoma (HCC) with pathologic correlations., Conclusion: The variant types of HCC may not share its typical imaging characteristics. An understanding of the radiologic findings for variant types of HCC can be helpful in the differential diagnosis of hepatic tumors.

Purpose: To determine the performance of gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance imaging (MRI) to differentiate focal eosinophilic infiltration (FEI) from metastasis., Materials and Methods: Gadobenate dimeglumine-enhanced MRI conducted in 38 patients (lesions of 43 metastases and 33 FEIs) with extrahepatic abdominal carcinoma were reviewed retrospectively. Images were divided into 2 sets. Set 1 was composed of precontrast MRI with dynamic phase images. Set 2 included hepatobiliary phase images in addition to the images of set 1. Two blinded radiologists independently categorized each set of images into 5 grades to differentiate metastases from FEI. The area under the receiver operating characteristic curve (Az) was calculated for each set of images. The observers evaluated the shape, signal intensity (SI), and enhancement pattern of the lesions in consensus., Results: The Az values for set 2 images (reader 1: 0.976, and reader 2: 0.743) were greater than those of set 1 (0.961 and 0.709), without statistical significance (P = 0.470 and 0.223). Target appearance was seen in 27 of 43 (63%) metastases on hepatobiliary phase imaging, but none on the FEI. Twenty-five (76%) of the 33 FEIs showed intermingled hypo-SI and iso-SI on hepatobiliary phase images with changing size and shape compared to the T2-weighted images, whereas none of the metastases did., Conclusion: Gadobenate dimeglumine-enhanced MRI may assist in the differentiation of FEI from metastasis by highlighting the distinctive features between them, even without hepatobiliary phase imaging.

Magnetic resonance imaging (MRI) has been widely used for evaluation of focal lesions associated with hepatic carcinogenesis including hepatocellular carcinoma (HCC). By providing better tissue contrast compared to ultrasonography and computed tomography, MRI is considered the most sensitive modality for diagnosis of HCC. Dynamic MRI using gadolinium-based extracellular fluid (ECF) agents is useful for detection of hypervascular tumors and lesion characterization but has limitations in the diagnosis of hypovascular HCCs and lesion characterization of nonhypervascular tumors. MRI using superparamagnetic iron oxide agents may be useful for detecting and characterizing lesions that were not seen on dynamic MRI using ECF agents, but finding well-differentiated HCC and differentiating it from a dysplastic nodule can be difficult in some cases. Hepatobiliary agents that can be used in both dynamic MRI and delayed hepatobiliary phase imaging have great potential for improving characterization of focal lesions associated with hepatic carcinogenesis. Further studies are necessary to determine their roles in evaluation and management of HCCs., (Copyright 2008 S. Karger AG, Basel.)