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Purpose: Repeated gadolinium-based contrast agent (GBCA)-enhanced MRIs are crucial in the diagnosis and follow-up of oncologic and chronic disorders in pediatric patients. The aim of the study was to evaluate the frequency and severity of adverse reactions to GBCAs in children after a single vs. multiple GBCA-enhanced abdomen MRIs., Material and Methods: All pediatric patients with at least one GBCA-enhanced abdominal MRI between 2009 and 2020 were retrospectively evaluated based on adverse reactions reports, according to the classification system of the American College of Radiology and guidelines on contrast agents of the European Society of Urogenital Radiology. A Student´s t-test analysis, a spearman ρ-correlation and a Chi-square test between the reported adverse reactions and the total number of GBCA applications, and the number of each applied GBCA was calculated. A p-value <0.05 was considered significant., Results: Of 623 patients with 964 GBCA-enhanced abdomen MRIs, there were 464 patients with only one and 159 patients with multiple GBCA administrations. Of 964 GBCA doses administrated, two cases with urticaria (mild allergy-like adverse reaction) and one case with vomiting (mild chemotoxic adverse reaction) were recorded (3/964 = 0.31%), but all the reports were in patients with multiple GBCA administration (3/159 = 1.89%). No adverse reactions in patients with a single GBCA administration were observed. The reported adverse reactions correlated significantly with the total number of GBCAs (p<0.001) and the number of each GBCA (p<0.001 or p = 0.002). The independent two-tailed t-tests, and the chi-square test were significant (p<0.001, p = 0.003)., Conclusion: GBCA-associated adverse reactions are rare and mostly mild, but initially well-tolerated GBCA could cause adverse reactions due to the increase likelihood of drug hypersensitivity upon repeated GBCA exposure., Competing Interests: Ahmed Ba-Ssalamah received honoraria and consultancy fees from Bayer, but not in relation to this manuscript. Dietmar Tamandl has received research grant and honoraria from Siemens Healthineers, but not in relation to this manuscript. The other authors declare no conflict of interest., (Copyright: © 2024 Hojreh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: Our aim was twofold. First, to validate Anali scores with and without gadolinium (ANALI Gd and ANALI NoGd ) in primary sclerosing cholangitis (PSC) patients. Second, to compare the ANALIs prognostic ability with the recently-proposed potential functional stricture (PFS)., Materials and Methods: This retrospective study included 123 patients with a mean age of 41.5 years, who underwent gadoxetic acid-enahnced MRI (GA-MRI). Five readers independently evaluated all images for calculation of ANALI Gd and ANALI NoGd scores based upon following criteria: intrahepatic bile duct change severity, hepatic dysmorphia, liver parenchymal heterogeneity, and portal hypertension. In addition, hepatobiliary contrast excretion into first-order bile ducts was evaluated on 20-minute hepatobiliary-phase (HBP) images to assess PFS. Inter- and intrareader agreement were calculated (Fleiss´and Cohen kappas). Kaplan-Meier curves were generated for survival analysis. ANALI NoGd , ANALI Gd , and PFS were correlated with clinical scores, labs and outcomes (Cox regression analysis)., Results: Inter-reader agreement was almost perfect (ϰ = 0.81) for PFS, but only moderate-(ϰ = 0.55) for binary ANALI NoGd . For binary ANALI Gd , the agreement was slightly better on HBP (ϰ = 0.64) than on arterial-phase (AP) (ϰ = 0.53). Univariate Cox regression showed that outcomes for decompensated cirrhosis, orthotopic liver transplantation or death significantly correlated with PFS (HR (hazard ratio) = 3.15, p < 0.001), ANALI NoGd (HR = 6.42, p < 0.001), ANALI Gd HBP (HR = 3.66, p < 0.001) and ANALI Gd AP (HR = 3.79, p < 0.001). Multivariate analysis identified the PFS, all three ANALI scores, and Revised Mayo Risk Score as independent risk factors for outcomes (HR 3.12, p < 0.001; 6.12, p < 0.001; 3.56, p < 0.001;3.59, p < 0.001; and 4.13, p < 0.001, respectively)., Conclusion: ANALI NoGd and GA-MRI-derived ANALI scores and PFS could noninvasively predict outcomes in PSC patients., Clinical Relevance Statement: The combined use of Anali scores and the potential functional stricture (PFS), both derived from unenhanced-, and gadoxetic acid enhanced-MRI, could be applied as a diagnostic and prognostic imaging surrogate for counselling and monitoring primary sclerosing cholangitis patients., Key Points: Primary sclerosing cholangitis patients require radiological monitoring to assess disease stability and for the presence and type of complications. A contrast-enhanced MRI algorithm based on potential functional stricture and ANALI scores risk-stratified these patients. Unenhanced ANALI score had a high negative predictive value, indicating some primary sclerosing cholangitis patients can undergo non-contrast MRI surveillance., Competing Interests: Compliance with ethical standards Guarantor The scientific guarantor of this publication is Dr. Ahmed Ba-Ssalamah. Conflict of interest Michael Trauner received grant support from Albireo, Cymabay, Falk, Gilead, Intercept, MSD, and Takeda, honoraria for consulting from BiomX, Boehringer Ingelheim, Falk, Genfit, Gilead, Intercept, Janssen, MSD, Novartis, Phenex, and Regulus, speaker fees from BMS, Falk, Gilead, Intercept and MSD, as well as travel support from Abbvie, Falk, Gilead, and Intercept. The other authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article. Nikolaos Kartalis is a member of the European Radiology Editorial Board. He has not taken part in the review or selection process of this article. Statistics and biometry Dr. Michael Weber kindly provided statistical advice for this manuscript. Informed consent Informed Consent was waived by the Institutional Review Board. Ethical approval Institutional Review Board approval was obtained. Ethics commission (EC), Nr: 2249/2016 Radiologic Diagnosis of Cholestatic Liver Disease; A Retrospective Data Analysis. Study subjects or cohorts overlap Some study subjects or cohorts have been previously reported in Poetter-Lang S, Messner A, Bastati N et al (2023) Diagnosis of functional strictures in patients with primary sclerosing cholangitis using hepatobiliary contrast-enhanced MRI: a proof-of-concept study. Eur Radiol 33(12):9022-9037. https://doi.org/10.1007/s00330-023-09915-3. In the above-mentioned previous study, this cohort was used to prove the efficacy of potential functional stricture (PFS) to diagnose dominant or functional stricture in patients with PSC using ERCP as the gold standard. In this current study, this cohort is used to compare between the Anali scores and PFS to predict the short-, and mid to long term outcome of PSC patients. Methodology RetrospectiveDiagnostic or prognostic studyPerformed at one institution, (© 2024. The Author(s).)

Over the past two decades, contrast-enhanced ultrasound (CEUS) has been established as a method complementary to B-mode ultrasound and color Doppler sonography for diagnosing vascular liver pathologies and interventions.The objective of this review is to elucidate the application of CEUS in diagnosing vascular pathologies and interventional procedures.Considering the limitations of ultrasound, CEUS presents a similar alternative to other imaging modalities, such as computed tomography and magnetic resonance imaging, for evaluating vascular pathologies, guiding interventions, identifying complications, and assessing outcomes post intervention. Due to its widespread availability and the absence of radiation exposure, CEUS should be employed as a primary modality. · CEUS plays an important role in the detection of vascular liver pathologies.. · CEUS is helpful in characterizing vascular pathologies.. · CEUS is helpful in guiding interventions and identifying complications.., Competing Interests: C. Görg received funding from Bracco Imaging. Bracco Imaging supported CEUS workshops at the University Hospital Marburg., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Competing Interests: Christian Görg received funding from Bracco Imaging. Bracco Imaging supported CEUS workshops at the University Hospital Marburg.

Objective: Arterial-phase artifacts are gadoxetic acid (GA)-enhanced MRI's major drawback, ranging from 5 to 39%. We evaluate the effect of dilution and slow injection of GA using automated fluoroscopic triggering on liver MRI arterial-phase (AP) acquisition timing, artifact frequency, and lesion visibility., Methods and Materials: Saline-diluted 1:1 GA was injected at 1 ml/s into 1413 patients for 3 T liver MRI. Initially, one senior abdominal radiologist, i.e., principal investigator (PI), assessed all MR exams and compared them to previous and follow-up images, as well as the radiology report on record, determining the standard of reference for lesion detection and characterization. Then, three other readers independently evaluated the AP images for artifact type (truncation (TA), transient severe motion (TSM) or mixed), artifact severity (on a 5-point scale), acquisition timing (on a 4-point scale) and visibility (on a 5-point scale) of hypervascular lesions ≥ 5 mm, selected by the PI. Artifact score ≥ 4 and artifact score ≤ 3 were considered significant and non-significant artifacts, respectively., Results: Of the 1413 exams, diagnostic-quality arterial-phase images included 1100 (77.8%) without artifacts, 220 (15.6%) with minimal, and 77 (5.4%) with moderate artifacts. Only 16 exams (1.1%) had significant artifacts, 13 (0.9%) with severe artifacts (score 4), and three (0.2%) non-diagnostic artifacts (score 5). AP acquisition timing was optimal in 1369 (96.8%) exams. Of the 449 AP hypervascular lesions, 432 (96.2%) were detected., Conclusion: Combined dilution and slow injection of GA with MR results in well-timed arterial-phase images in 96.8% and a reduction of exams with significant artifacts to 1.1%., Clinical Relevance Statement: Hypervascular lesions, in particular HCC detection, hinge on arterial-phase hyperenhancement, making well-timed, artifact-free arterial-phase images a prerequisite for accurate diagnosis. Saline dilution 1:1, slow injection (1 ml/s), and automated bolus triggering reduce artifacts and optimize acquisition timing., Key Points: • There was substantial agreement among the three readers regarding the presence and type of arterial-phase (AP) artifacts, acquisition timing, and lesion visibility. • Impaired AP hypervascular lesion visibility occurred in 17 (3.8%) cases; in eight lesions due to mistiming and in nine lesions due to significant artifacts. • When AP timing was suboptimal, it was too late in 40 exams (3%) and too early in 4 exams (0.2%) of exams., (© 2024. The Author(s).)

Background Gadoxetic acid-enhanced MRI enables estimation of liver function in patients with chronic liver disease (CLD). The functional liver imaging score (FLIS), derived from gadoxetic acid-enhanced MRI, has been shown to predict transplant-free survival in liver transplant patients. Purpose To investigate the accuracy of the FLIS for predicting hepatic decompensation and transplant-free survival in patients with CLD. Materials and Methods Patients with CLD who had undergone gadoxetic acid-enhanced liver MRI, including T1-weighted volume-interpolated breath-hold examination sequences with fat suppression, performed between 2011 and 2015 were included. FLIS was assigned on the basis of the sum of three hepatobiliary phase features, each scored on an ordinal 0-2 scale: hepatic enhancement, biliary excretion, and the signal intensity in the portal vein. Patients were stratified into the following three groups according to fibrosis stage and a presence or history of hepatic decompensation: nonadvanced CLD, compensated advanced CLD (CACLD), and decompensated advanced CLD (DACLD). The predictive value of FLIS for first and/or further hepatic decompensation and for transplant-free survival was investigated by using Kaplan-Meier analysis, log-rank tests, and Cox regression analysis. Results This study evaluated 265 patients (53 years ± 14 [standard deviation]; 164 men). Intraobserver (κ = 0.98; 95% confidence interval: 0.97, 0.99) and interobserver (κ = 0.93; 95% confidence interval: 0.90, 0.95) agreement for FLIS were excellent. In patients with CACLD, the FLIS was independently predictive of a first hepatic decompensation (adjusted hazard ratio, 3.7; 95% confidence interval: 1.1, 12.6; P = .04), but not for further hepatic decompensations in patients with DACLD (adjusted hazard ratio, 1.4; 95% confidence interval: 0.9, 1.9; P = .17). The FLIS was an independent risk factor for mortality in both patients with CACLD (adjusted hazard ratio, 7.4; 95% confidence interval: 2.7, 20.2; P < .001) and those with DACLD (adjusted hazard ratio, 3.8; 95% confidence interval: 1.7, 9.5; P = .004). Conclusion The functional liver imaging score derived from gadoxetic acid-enhanced MRI identified patients with advanced chronic liver disease who are at increased risk for a first hepatic decompensation and for mortality. © RSNA, 2019 Online supplemental material is available for this article.

Rationale and Objectives: This study aimed to investigate the potential of contrast-enhanced magnetic resonance imaging features to differentiate between mass-forming intrahepatic cholangiocellular carcinoma (ICC) and hepatocellular carcinoma (HCC) in cirrhotic livers., Materials and Methods: This study, performed between 2001 and 2013, included 64 baseline magnetic resonance imaging examinations with pathohistologically proven liver cirrhosis, presenting with either ICC (n = 32) or HCC (n = 32) tumors. To distinguish ICC form HCC tumors, 20 qualitative single-lesion descriptors were evaluated by two readers, in consensus, and statistically classified using the chi-square automatic interaction detection (CHAID) methodology. Diagnostic performance was assessed by a receiver operating characteristic analysis., Results: The CHAID algorithm identified three independent categorical lesion descriptors, including (1) liver capsular retraction; (2) progressive or persistent enhancement pattern or wash-out on the T1-weighted delayed phase; and (3) signal intensity appearance on T2-weighted images that could help to reliably differentiate ICC from HCC, which resulted in an AUC of 0.807, and a sensitivity and specificity of 68.8 and 90.6 (95% confidence interval 75.0-98.0), respectively., Conclusions: The proposed CHAID algorithm provides a simple and robust step-by-step classification tool for a reliable and solid differentiation between ICC and HCC tumors in cirrhotic livers., (Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Purpose: To determine which of three gadoxetic acid injection techniques best reduced the contrast-related arterial-phase motion artifacts., Materials and Methods: This Institutional Review Board (IRB)-approved, retrospective study included a cohort of 78 consecutive patients who each had serial gadoxetic acid-enhanced 3.0T magnetic resonance imaging (MRI) of the liver (0.025 mmol/kg body weight) performed with at least two of three injection techniques: M1 test bolus, undiluted, power-injected 1 mL/s; M2 test bolus, diluted 50% with saline, power-injected 1 mL/s; M3 fixed delay, undiluted, manually injected. Blinded to the injection method, three readers independently rated the randomized images for arterial-phase motion artifacts, arterial-phase timing, and arterial-phase lesion visibility using a four-point Likert scale., Results: Regarding respiratory artifacts, gadoxetic acid arterial-phase images were judged better with M3 (2.7 ± 0.7) and were significantly less than those with M1 (2.1 ± 1.1) (P = 0.0001). Arterial-phase M2 (2.50 ± 0.89) images were rated significantly better than arterial-phase M1 images (P = 0.012), but the difference between arterial-phase images with M3 and M2 scores was not statistically significant (P = 0.49). Arterial-phase timing was significantly better for M1 compared to M3, and for M2 compared to M3 (P < 0.0001 for both). The area under the curve was 0.59-0.68. However, there was no significant difference between M1 and M2 (P = 0.35). With regard to arterial-phase lesion visibility, there was no significant difference in the ratings between any of the three injection techniques (P = 0.29-0.72). Interreader agreement was moderate to substantial (κ = 0.41-0.62)., Conclusion: A diluted, power-injected protocol (M2) seems to provide good timing and minimize artifacts compared with two other injection methods. No significant difference was found in lesion visibility between these three methods., Level of Evidence: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1107-1114., (© 2017 International Society for Magnetic Resonance in Medicine.)

Objective: The aim of this study was to investigate the impact of portal hypertension (PH) on gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) and assess diagnostic and prognostic implications in comparison to established imaging features of PH., Materials and Methods: Institutional review board-approved retrospective study of 178 patients (142 men; median age, 59.4 years) with chronic liver disease undergoing MRI and hepatic venous pressure gradient (HVPG) measurement between January 2008 and April 2015. Magnetic resonance imaging was assessed for established features of PH (splenic and portal vein diameters, portosystemic collaterals, ascites) and for features on 20 minutes delayed T1-weighted gadoxetic acid-enhanced MRI, that is, relative liver enhancement (RLE), biliary contrast excretion, or portal vein hyperintensity or isointensity (ie, portal vein hyperintensity sign, PVHS). Statistics encompassed linear regression, logistic regression, and survival analysis., Results: There was an inverse correlation between HVPG and RLE (r = 0.18, P < 0.0001). On univariate analysis, clinically significant PH (ie, HVPG ≥ 10 mm Hg, n = 109) and severe PH (ie, HVPG ≥ 12 mm Hg, n = 99) were associated with delayed biliary contrast excretion (n = 33) and the PVHS (n = 74) (P < 0.01 for all). Multivariate analysis demonstrated significant associations between the PVHS and severe PH (odds ratio [OR], 3.33; P = 0.008), independently of spleen size (OR, 1.26; P = 0.002), portosystemic collaterals (n = 81; OR, 5.46; P = 0.0001), and ascites (n = 88; OR, 3.24; P = 0.006). Lower RLE and the PVHS were associated with lower 3-year, transplantation-free survival (hazards ratios, 0.98 and 3.99, respectively, P = 0.002 for all), independently of the Child-Pugh and Model for End-Stage Liver Disease scores., Conclusions: The presence of the PVHS on gadoxetic acid-enhanced MRI is an independent indicator of severe PH and may enable more accurate diagnosis. This feature and decreased hepatic contrast uptake may also comprise prognostic information.

Objective: The aim of this study was to evaluate the prognostic potential of a 3-parameter visual scoring (qualitative score [QS]) system for hepatobiliary phase gadoxetic acid-enhanced magnetic resonance imaging (MRI) in orthotopic liver transplant grafts., Materials and Methods: This retrospective study of 128 patients was approved by our institutional review board. Two readers independently assigned 3 QSs to T1-weighted MRI scans, 20 minutes after the administration of gadoxetic acid (hepatobiliary phase), based upon the following: (1) liver parenchymal enhancement (EnQS, 0-2); (2) biliary contrast excretion (ExQS, 0-2); and (3) signal intensity of the portal vein relative to the liver parenchyma, that is, the portal vein sign (PVsQS, 0-2). The functional liver imaging score (FLIS) was calculated as the sum score of these 3 parameters. The relative liver enhancement (RLE) was measured as well. Demographic, clinical, laboratory parameters, and imaging findings were included in univariate and multivariate statistical analyses. The primary end point was graft failure, that is, retransplantation or death from liver failure. The probability of graft survival was calculated by Kaplan-Meier estimates and Cox proportional hazards regression., Results: In the univariate analysis, EnQS, ExQS, PVsQS, and FLIS scores, as well as RLE, were significantly associated with the 1- to 3-year probability of graft survival (P < 0.001). For a FLIS of (0), the 3-year probability of graft survival was 6.5%, whereas it was 51.3% for a FLIS of (1-3) and 100% for a FLIS of (4-6) (P < 0.001). In the multivariate survival models, EnQS, ExQS, and PVsQS, each independently outperformed the majority of clinical and laboratory parameters, and the FLIS did even better regarding the prediction of 1- to 3-year graft survival., Conclusions: In liver transplant recipients, gadoxetic acid-enhanced MRI-derived QSs (ie, EnQS, ExQS, and PVsQS), as well as the FLIS and RLE, can predict graft survival probability.

Objectives: To assess the costs of diagnostic workup and surgery of three strategies for patients with colorectal cancer liver-metastases (CRCLM): gadoxetic-acid-enhanced MRI (Gd-EOB-DTPA-MRI), MRI with extracellular contrast-media (ECCM-MRI) or contrast-enhanced MDCT (CE-MDCT)., Methods: The within-trial cost evaluation was modelled as a decision-tree to calculate the cost of diagnosis and surgery. The model used clinical outcomes and resource utilization data from a prospective randomized multicentre study. Analyses were performed for the 354-patient safety population from eight participating countries., Results: The diagnostic workup cost using Gd-EOB-DTPA-MRI upfront resulted in savings compared to ECCM-MRI in all countries except Thailand (difference <2 %). Compared to CE-MDCT, initial imaging with Gd-EOB-DTPA-MRI was less costly in all countries except Korea and Spain (differences 4 and 8 %, respectively). Significantly more patients in the Gd-EOB-DTPA-MRI group were eligible for surgery (39.3 % (48/122) vs. 31.0 % (36/116) and 26.7 % (31/116) for ECCM-MRI and CE-MDCT, respectively), allowing more patients to undergo potentially curative surgery, but resulting in higher treatment costs for the strategy starting with Gd-EOB-DTPA-MRI., Conclusions: The benefits of Gd-EOB-DTPA-MRI due to less additional imaging and similar diagnostic workup costs in the three groups suggest that Gd-EOB-DTPA-MRI should be the preferred initial imaging procedure to evaluate hepatic resectability in patients with CRCLM., Key Points: • Diagnostic imaging cost to evaluate resectability was similar among the groups • Cost for imaging was rather small compared to the cost of surgery • Significantly more patients in the Gd-EOB-DTPA-MRI arm were eligible for surgery • Gd-EOB-DTPA-MRI is recommended for evaluating hepatic resectability in patients with CRCLM.

Objectives: To develop a consensus and provide updated recommendations on liver MR imaging and the clinical use of liver-specific contrast agents., Methods: The European Society of Gastrointestinal and Abdominal Radiology (ESGAR) formed a multinational European panel of experts, selected on the basis of a literature review and their leadership in the field of liver MR imaging. A modified Delphi process was adopted to draft a list of statements. Descriptive and Cronbach's statistics were used to rate levels of agreement and internal reliability of the consensus., Results: Three Delphi rounds were conducted and 76 statements composed on MR technique (n = 17), clinical application of liver-specific contrast agents in benign, focal liver lesions (n = 7), malignant liver lesions in non-cirrhotic (n = 9) and in cirrhotic patients (n = 18), diffuse and vascular liver diseases (n = 12), and bile ducts (n = 13). The overall mean score of agreement was 4.84 (SD ±0.17). Full consensus was reached in 22 % of all statements in all working groups, with no full consensus reached on diffuse and vascular diseases., Conclusions: The consensus provided updated recommendations on the methodology, and clinical indications, of MRI with liver specific contrast agents in the study of liver diseases., Key Points: • Liver-specific contrast agents are recommended in MRI of the liver. • The hepatobiliary phase improves the detection and characterization of hepatocellular lesions. • Liver-specific contrast agents can improve the detection of HCC.

Purpose: To assess the diagnostic efficacy of multiparametric MRI using quantitative measurements of the apparent diffusion coefficient (ADC) of the liver parenchyma on diffusion-weighted imaging (DWI), signal intensity (SI) on susceptibility-weighted imaging (SWI), and gadoxetic acid-enhanced T1-weighted imaging during the hepatobiliary phase for the staging of liver fibrosis., Materials and Methods: Seventy-seven patients underwent a 3T MRI examination, including DWI/SWI sequences and gadoxetic acid-enhanced T1-weighted MRI. Liver fibrosis according to liver biopsy was staged using the Metavir fibrosis score: F0 (n = 21, 27.3%); F1 (n = 7, 9.1%); F2 (n = 8, 10.4%); F3 (n = 12, 15.6%); and F4 (n = 29, 37.7%). SI of the liver was defined using region-of-interest measurements to calculate the ADC values, the relative enhancement (RE) in the hepatobiliary phase, and the liver-to-muscle ratio (LMR) measurements for SWI., Results: The values of RE, LMR, and ADC measurements were statistically significantly different among the five fibrosis stages (p < 0.004). Combining the three parameters in a multiparametric approach, the AUC for detecting F1 stage or greater (≥ F1) was 94%, for F2 or greater (≥F2) was 95%, for F3 or greater (≥F3) was 90%, and for stage F4 was 93%., Conclusions: Multiparametric MRI is an efficient non-invasive diagnostic tool for the staging of liver fibrosis., Key Points: • Multiparametric MRI has high accuracy in predicting moderate or greater liver fibrosis. • Relative enhancement post- gadoxetic acid is an independent predictor of liver fibrosis. • Liver SWI signal intensity and ADC values enhance the diagnostic ability.

Purpose: To evaluate the diagnostic performance of imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging to differentiate among hepatocellular adenoma (HCA) subtypes by using the histopathologic results of the new immunophenotype and genotype classification and to correlate the enhancement pattern on the hepatobiliary phase (HBP) with the degrees of expression of organic anion transporting polypeptide (OATP1B1/3), multidrug resistance-associated protein 2 (MRP) (MRP2), and MRP 3 (MRP3) transporters., Materials and Methods: This retrospective study was approved by the institutional review board, and the requirement for informed consent waived. MR imaging findings of 29 patients with 43 HCAs were assessed by two radiologists independently then compared with the histopathologic analysis as the standard of reference. Receiver operating characteristic curves and Spearman rank correlation coefficient were used to test the diagnostic performance of gadoxetic acid-enhanced MR imaging features, which included the retention or washout at HBP and degree of transporter expression. Interreader agreement was assessed by using the κ statistic with 95% confidence interval., Results: The area under the curve for the diagnosis of inflammatory HCA was 0.79 (95% confidence interval: 0.64, 0.90); for the steatotic type, it was 0.90 (95% confidence interval: 0.77, 0.97); and for the β-catenin type, it was 0.87 (95% confidence interval: 0.74, 0.95). There were no imaging features that showed a significant statistical correlation for the diagnosis of unclassified HCAs. On immunohistochemical staining, OATP1B1/3 expression was the main determinant for the retention, whereas MRP3 was the key determinant for washout of gadoxetic acid at HBP (P < .001). MRP2 appeared to have no role., Conclusion: Gadoxetic acid-enhanced MR imaging features may suggest the subtype of HCA. The degree of OATP1B1/3 and MRP3 expression correlated statistically with gadoxetic acid retention and washout, respectively, in the HBP., ((©) RSNA, 2015 Online supplemental material is available for this article.)

Purpose: To determine whether gadoxetic acid-enhanced magnetic resonance (MR) imaging can be used to distinguish between simple steatosis and nonalcoholic steatohepatitis (NASH) in patients with nonalcoholic fatty liver disease (NAFLD), defined according to the steatosis activity and fibrosis (SAF) scoring system, which is based on the semiquantitative scoring of steatosis activity and liver fibrosis., Materials and Methods: The local institutional review committee approved this study and waived written informed consent. This was a retrospective study of gadoxetic acid-enhanced 3-T MR imaging performed in 81 patients with NAFLD (45 men [56%]; mean age, 56 years; range, 25-78 years). The MR images were analyzed by using the relative enhancement (the ratio of signal intensities of the liver parenchyma before and 20 minutes after intravenous administration of gadoxetic acid). Univariate and multiple regression analyses were applied to identify variables associated with relative enhancement measurements. The ability of relative enhancement to allow differentiation between simple steatosis and NASH was assessed by using area under the receiver operating characteristic (ROC) curve analysis., Results: Relative enhancement negatively correlated with the degree of lobular inflammation (r = -0.59, P < .0001), ballooning (r = -0.44, P < .0001), and fibrosis (r = -0.59, P ≤ .0001), but not with steatosis (r = -0.16, P = .15). Patients with NASH had a significantly lower relative liver enhancement (0.82 ± 0.22) than those with simple steatosis (1.39 ± 0.52) (P < .001). Relative enhancement measurements performed well in the differentiation between simple steatosis and NASH, with an area under the ROC curve of 0.85 (95% confidence interval: 0.75, 0.91) (cutoff = 1.24, sensitivity = 97%, specificity = 63%)., Conclusion: Gadoxetic acid relative enhancement was significantly lower in patients with NASH than in patients with simple steatosis, but further prospective studies are warranted.

Aim: To evaluate the value of gadoxetic acid-enhanced T1-weighted (T1W) magnetic resonance cholangiography (MRC) versus conventional T2-weighted (T2W) MRC compared to endoscopic retrograde cholangiopancreatography (ERCP) in patients with primary sclerosing cholangitis (PSC)., Materials and Methods: Based on T1W MRC, PSC patients were classified into a regular (RG) and a delayed (DG) excreting group, with an absence of gadoxetic acid in the common bile duct at 20 min. Beading, pruning, and gradation of central bile duct stenosis, evaluated by T1W and T2W MRC, were compared to ERCP. Liver parenchymal enhancement was measured in both study groups and compared to a reference group (n = 20) without a history of liver disease. Two readers performed all measurements., Results: Based on beading and pruning of the peripheral bile ducts, sensitivities, specificities, and accuracies for reader 1 were 0.17/0.43, 0/0.17, and 0.15/0.31 for T1W MRC, and 0.83/0.86, 1/0.83, and 0.85/0.85 for T2W MRC (p = 0.004). For reader 2 sensitivities, specificities, and accuracies were 0.25/0.57, 0/0.33, and 0.23/0.46 for T1W MRC, and 0.92/1, 1/0.83, and 0.92/0.92 for T2W MRC (p = 0.012). Compared to ERCP, central bile duct stenoses were significantly overestimated (p < 0.001) by T2W MRC. A significantly lower parenchymal enhancement was found in the DG (n = 7) compared to the RG (n = 13), and compared to the reference group (p < 0.001)., Conclusion: The combined performance of T2W and T1W MRC may provide a comprehensive imaging workup of PSC, including morphological and functional information resulting in optimal management., (Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: This multicentre international randomized trial compared the impact of gadoxetic acid-enhanced magnetic resonance imaging (MRI), MRI with extracellular contrast medium (ECCM-MRI) and contrast-enhanced computed tomography (CE-CT) as a first-line imaging method in patients with suspected colorectal cancer liver metastases (CRCLM)., Methods: Between October 2008 and September 2010, patients with suspected CRCLM were randomized to one of the three imaging modalities. The primary endpoint was the proportion of patients for whom further imaging after initial imaging was required for a confident diagnosis. Secondary variables included confidence in the therapeutic decision, intraoperative deviations from the initial imaging-based surgical plan as a result of additional operative findings, and diagnostic efficacy of the imaging modalities versus intraoperative and pathological extent of the disease., Results: A total of 360 patients were enrolled. Efficacy was analysed in 342 patients (118, 112 and 112 with gadoxetic acid-enhanced MRI, ECCM-MRI and CE-CT respectively as the initial imaging procedure). Further imaging was required in 0 of 118, 19 (17.0 per cent) of 112 and 44 (39.3 per cent) of 112 patients respectively (P < 0.001). Diagnostic confidence was high or very high in 98.3 per cent of patients for gadoxetic acid-enhanced MRI, 85.7 per cent for ECCM-MRI and 65.2 per cent for CE-CT. Surgical plans were changed during surgery in 28, 32 and 47 per cent of patients in the respective groups., Conclusion: The diagnostic performance of gadoxetic acid-enhanced MRI was better than that of CE-CT and ECCM-MRI as the initial imaging modality. No further imaging was needed in the gadoxetic acid-enhanced MRI group and comparison of diagnostic efficacy parameters demonstrated the diagnostic superiority of gadoxetic acid-enhanced MRI., Registration Number: NCT00764621(http://clinicaltrials.gov); EudraCT number: 2008-000583-16 (https://eudract.ema.europa.eu/)., (© 2014 The Authors. BJS published by John Wiley & Sons Ltd on behalf of BJS Society Ltd.)

Objectives: The aim of this prospective study was to compare the diagnostic performance of 64-row MDCT and gadoxetic-acid-enhanced MRI at 3.0 T in patients with colorectal liver metastases in correlation with histopathological findings., Methods: Lesions detected at MDCT and MRI were interpreted by three blinded readers and compared with histopathological workup as the term of reference. Two subgroups of lesions were additionally evaluated: (1) metastases smaller than 10 mm and (2) lesions in patients with and without steatosis of the liver, assessed histopathologically., Results: Surgery and histopathological workup revealed 81 colorectal liver metastases in 35 patients and diffuse metastatic involvement in 3 patients. In a lesion-by-lesion analysis, significant sensitivity differences could only be found for reader 1 (P = 0.035) and reader 3 (P = 0.003). For segment-based evaluation, MRI was more sensitive only for reader 3 (P = 0.012). The number of false-positive results ranged from 3 to 12 for MDCT and 8 to 11 for MRI evaluation. In the group of small lesions, the sensitivity differed significantly between both methods (P = 0.003). In patients with hepatic steatosis, MRI showed a trend toward better performance than MDCT, but without statistical performance., Conclusions: The 3.0-T MRI with liver-specific contrast agents is the preferred investigation in the preoperative setting, especially for the assessment of small colorectal liver metastases., Key Points: • Potential surgical treatment requires accurate radiological assessment of colorectal liver metastases • Magnetic resonance imaging with gadoxetic acid is the preferred imaging investigation. • MRI is better than multidetector CT for detecting small liver metastases.

Objectives: To evaluate the diagnostic value of dynamic MRI swallowing in patients with symptoms of Gastroesophageal Reflux Disease (GERD)., Methods: Thirty-seven patients (17 m/20f) with typical signs of GERD underwent MR swallowing in the supine position at 1.5 T with a phased-array body coil. Using dynamic, gradient echo sequences (B-FFE) in the coronal, sagittal and axial planes, the bolus passages of buttermilk spiked with gadolinium chelate were tracked. MRI, pH-metry and manometry were performed within 31 days and results were compared., Results: MRI results were concordant with pH-metry in 82% (23/28) of patients diagnosed with abnormal oesophageal acid exposure by pH-metry. Five patients demonstrated typical symptoms of GERD and had positive findings with pH monitoring, but false negative results with MRI. In four of six patients (67%), there was a correct diagnosis of oesophageal motility disorder, according to manometric criteria, on dynamic MRI. The overall accuracy of MRI diagnoses was 79% (27/34). A statistically significant difference was found between the size of hiatal hernia, grade of reflux in MRI, and abnormal acid exposure on pH-monitoring., Conclusions: MR fluoroscopy may be a promising radiation-free tool in assessing the functionality and morphology of the GE junction., Key Points: • Swallowing MRI can assess anatomy and function of the gastroesophageal-junction • Swallowing MRI can help identifying reflux and motility disorders • Definition of the size of hiatal hernias is possible in all three planes in MR. • Short duration of swallowing MRI enables its application in routine clinical practice.

Purpose: To compare the diagnostic performance (detection, local staging) of multiphasic 64-detector row computed tomography (CT) with that of gadobenate dimeglumine-enhanced 3.0-T magnetic resonance (MR) imaging in patients suspected of having pancreatic cancer., Materials and Methods: The institutional review board approved this prospective study, and all patients provided written informed consent. Multidetector CT and MR imaging were performed in 89 patients (48 women aged 46-89 years [mean, 65.6 years] and 41 men aged 46-86 years [mean, 65.3 years]) suspected of having pancreatic cancer on the basis of findings from clinical examination or previous imaging studies. Two readers independently assessed the images to characterize lesions and determine the presence of focal masses, vascular invasion, distant metastases, and resectability. Findings from surgery, biopsy, endosonography, or follow-up imaging were used as the standard of reference. Logistic regression, the McNemar test, and κ values were used for statistical analysis., Results: Focal pancreatic masses were present in 63 patients; 43 patients had adenocarcinoma. For reader 1, the sensitivities and specificities in the detection of pancreatic adenocarcinoma were 98% (42 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 98% (42 of 43 patients) and 96% (44 of 46 patients) for MR imaging. For reader 2, the sensitivities and specificities were 93% (40 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 95% (41 of 43 patients) and 96% (44 of 46 patients) for MR imaging. Vessel infiltration was determined in 22 patients who underwent surgery, and reader 1 obtained sensitivities and specificities of 90% (nine of 10 vessels) and 98% (119 of 122 vessels), respectively, for CT and 80% (eight of 10 vessels) and 96% (117 of 122 vessels) for MR imaging; for reader 2, those values were 70% (seven of 10 vessels) and 98% (120 of 122 vessels) for CT and 50% (five of 10 vessels) and 98% (120 of 122 vessels) for MR imaging. Both readers correctly assessed resectability in 87% (13 of 15 patients) of cases with CT and 93% (14 of 15 patients) of cases with MR imaging. Nonresectability was assessed correctly with CT in 75% (six of eight patients) of cases by reader 1 and 63% (five of eight patients) of cases by reader 2; nonresectability was correctly assessed with MR imaging in 75% (six of eight patients) of cases by reader 1 and 50% (four of eight patients) of cases by reader 2. None of the differences between modalities and readers were statistically significant (P > .05)., Conclusion: Both CT and MR imaging are equally suited for detecting and staging pancreatic cancer., Supplemental Material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101189/-/DC1., (RSNA, 2011)

MRI has become the most important imaging modality for detecting and characterizing focal liver lesions. The introduction of high-field-strengths, such as 3 Tesla MR imaging, in combination with the parallel imaging technique, has led to significant improvements in spatial and temporal resolution and has established this technique as a valuable asset in daily clinical practice. New techniques, such as diffusion-weighted imaging, may improve MR imaging sensitivity and specificity in the diagnostic workup of focal liver lesions. The tailored administration of various nonspecific and liver-specific contrast agents enables clinicians to increase the detection rate and improve the characterization of the different focal liver lesions. This article describes the usefulness of these imaging techniques in detecting and characterizing the most common benign focal liver lesions., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.

The intravenous administration of a standard dose of conventional gadolinium-based contrast agents produces higher contrast between the tumor and normal brain at 3.0 Tesla (T) than at 1.5 T, which allows reducing the dose to half of the standard one to produce similar contrast at 3.0 T compared to 1.5 T. The assessment of cumulative triple-dose 3.0 T images obtained the best results in the detection of brain metastases compared to other sequences. The contrast agent dose for dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging at 3.0 T can be reduced to 0.1 mmol compared to 0.2 mmol at 1.5 T due to the increased susceptibility effects at higher magnetic field strengths. Contrast agent application makes susceptibility-weighted imaging (SWI) at 3.0 T clinically attractive, with an increase in spatial resolution within the same scan time. Whereas a double dose of conventional gadolinium-based contrast agents was optimal in SWI with respect to sensitivity and image quality, a standard dose of gadobenate dimeglumine, which has a two-fold higher T1-relaxivity in blood, produced the same effect. For MR-arthrography, optimized concentrations of gadolinium-based contrast agents are similar at 3.0 and 1.5 T. In summary, high field MRI requires the optimization of the contrast agent dose in different clinical applications.

Objectives: We sought to determine the optimal dose of a contrast agent with known high relaxivity on 1.5 and 3 Tesla scanners that would achieve the best compromise between image quality and scan time for the clinical application of contrast-enhanced susceptibility-weighted imaging (CE-SWI)., Methods: Pre- and postcontrast SWI was performed with different contrast agent doses (0.05, 0.1, and 0.2 mmol/kg gadobenate dimeglumine) at both 1.5 and 3 T in 6 healthy volunteers, resulting in 72 examinations. Venograms were created from minimum intensity projection reconstructions over specified deep white matter volumes to enhance the visual appearance of connected venous structures. Three independent radiologists blindly rated the visibility of the veins on a continuous scale of 1 to 10. A general linear model was used for statistical evaluation, with fixed effects of the contrast agent dose, the field strength, the rater and the patients as a random effect., Results: With CE-SWI, we found significant differences in the visibility of the deep veins dependent on the contrast media dose (P=0.02). At 3 T, the visibility of deep venous vessels, with regard to susceptibility effect, image quality, and scan time reduction after a standard contrast agent dose 0.1 mmol/kg was significantly better than that achieved with 0.05 mmol/kg. The visibility was considered equal with 0.1 mmol/kg of the contrast agent to the precontrast images and a dose of 0.2 mmol/kg. At 1.5 T, no significant difference was found between the 4 contrast agent doses. We found no difference in the visibility of the veins with the shorter sequences at 3 T compared with the sequences at 1.5 T., Conclusions: Only a standard dose (0.1 mmol/kg) of gadobenate dimeglumine is required to achieve the optimum susceptibility effect and image quality at 3 T, together with a reduced scan time. This result can be attributed to the higher relaxivity of gadobenate dimeglumine, compared with conventional gadolinium chelates.

Purpose: To assess the value of mangafodipir trisodium-enhanced MR imaging for characterization of hepatocellular lesions., Materials and Methods: Magnetic resonance images of 41 patients with 48 histopathologically proven hepatocellular lesions (20 cases of focal nodular hyperplasia [FNH], 4 adenomas, 15 hepatocellular carcinomas [HCCs], 7 regenerative nodules, and 2 others) were retrospectively studied. Magnetic resonance imaging was performed on a 1.5-T unit (Vision, Siemens, Erlangen, Germany; ACS-NT, Philips, Best, The Netherlands) using T2-weighted, fat-saturation, turbo spin echo imaging and T1-weighted gradient echo imaging before and 20 minutes after infusion of 5 micromol/kg mangafodipir (Amersham Health, Oslo, Norway). Qualitative analysis by 4 blinded independent readers included assessment of unenhanced images and, in a second step, assessment of unenhanced and contrast-enhanced images together. Lesions were classified as benign or malignant using a 5-point scale, and readers made a specific diagnosis., Results: For characterization of hepatocellular lesions, mangafodipir-enhanced imaging was significantly superior to unenhanced imaging (P < 0.05). On receiver operating characteristic analysis, the area under the curve was 0.768 (95% confidence interval: 0.633-0.903) for unenhanced images and 0.866 (95% confidence interval: 0.767-0.966) for evaluation of unenhanced and contrast-enhanced images together (P < 0.05). Analysis of enhancement patterns aided in characterization and classification of tumors., Conclusion: Administration of mangafodipir improves the differentiation between adenoma or HCC and "nonsurgical" lesions (FNH or regenerative nodules). The accuracy for arriving at a specific diagnosis is higher when unenhanced and mangafodipir-enhanced images are considered together than for unenhanced MR images alone.

The liver is a common site for various benign and malignant focal lesions. The initial modality for assessing liver lesions is ultrasound or CT. MRI with its superior soft tissue contrast offers multiple advantages over other imaging modalities. Contrast agents have been developed that increase the detection rate and provide more specific information in comparison to unenhanced techniques. In the mean time three classes are available for MR imaging of the liver: extracellular gadolinium chelates, hepatobiliary and reticulo-endothelia, superparamagnetic agents. We describe in this review the most common focal lesions, their diagnostic possibilities, and the imaging protocols. Clinical use of these contrast agents facilitates detection and differential diagnosis of focal liver lesions that may help to avoid invasive procedures such as biopsy for lesion characterization.

The basic diagnostic efficacy of MR contrast medium in the evaluation of primary brain tumors and its clinical usefulness in the detection of brain metastases with single and cumulative triple-dose was compared using a high-field 3 T MR unit and a 1.5 T MR unit. Additionally, the effect of contrast agent on high-resolution MR venography based on the BOLD effect was evaluated at both field strengths. Tumor-brain contrast after gadodiamide administration, as assessed by means of statistical evaluation of MP-RAGE scans and T1-SE images, was significantly higher at 3 T than at 1.5 T. The subjective assessment of cumulative triple-dose 3 T images obtained the best results in the detection of brain metastases, followed by 1.5 T cumulative triple-dose enhanced images. Due to higher spatial resolution, contrast-enhanced MR venography at 3 T showed more details in and around tumors than at 1.5 T, additionally enhanced by stronger susceptibility weighting and higher signal-to-noise ratio at 3 T. In summary, administration of gadolinium-based contrast agent produces higher contrast between tumor and normal brain at 3 T than at 1.5 T, helps to detect more cerebral metastases at 3 T than at 1.5 T in single and cumulative triple dose, and improves MR venography at 3 T with increase in spatial resolution within the same measurement time, thus providing more detailed information.

Tumor-to-brain contrast after gadolinium administration using MP-RAGE and T1-SE scans in patients with primary and secondary brain tumors was significantly higher at 3 T than at 1.5 T. The subjective assessment of cumulative triple-dose 3 Tesla images obtained the best results in the detection of brain metastases compared with other sequences followed by 1.5 T cumulative triple-dose enhanced images. In macroadenomas of the hypophysis, contrast-enhanced 3 T MRI was superior to standard MRI in the diagnosis of cavernous sinus infiltration and in visualization of cranial nerves within the cavernous sinus. Due to higher spatial resolution, contrast-enhanced MR venography at 3 T showed more details in and around tumors than at 1.5 T, additionally enhanced by stronger susceptibility weighting and higher signal-to-noise ratio at 3 T. In summary, administration of gadolinium-based contrast agent produces higher contrast between tumor and normal brain at 3 T than at 1.5 T, helps to detect more cerebral metastases at 3 T versus 1.5 T in single and cumulative triple dose, improves the evaluation of macroadenomas of the hypophysis, and makes MR venography at 3 T clinically attractive with increase in spatial resolution within the same measurement time, thus providing more detailed information.

Purpose: To compare the diagnostic efficacy of a standard and cumulative triple dose of magnetic resonance (MR) imaging contrast agent in the evaluation of brain metastases using a high-field 3.0 T MR unit versus a standard field 1.5 T MR unit., Methods: Twenty-two patients with suspected brain metastases were examined at both field strengths using identical postcontrast coronal 3D gradient echo with magnetization preparation, which was adjusted separately for each field strength. In both groups initially, iv injection of 0.1 mmol/kg body weight gadolinium chelate (gadodiamide) and thereafter, 0.2 mmol/kg body weight gadodiamide were administered. Subjective assessment of the images was performed independently by 3 neuroradiologists. Objective measurement of signal-to-noise and contrast-to-noise ratios was obtained., Results: The subjective assessment of cumulative triple-dose 3.0 T images obtained the best results compared with other sequences, detecting 84 metastases, followed by 1.5 T cumulative triple-dose enhanced images with 81 brain metastases. The objective assessment confirmed those results, showing significantly higher signal-to-noise and contrast-to-noise ratios with 3.0 T than with 1.5 T., Conclusions: Cumulative triple-dose images of both field strengths were superior to standard field strengths. However, administration of gadodiamide contrast agent produces higher contrast between tumor and normal brain on 3.0 T than on 1.5 T, resulting in better detection of brain metastases and leptomeningeal involvement.

Objective: The objective of our study was to describe the functional and differential uptake features of atypical focal nodular hyperplasia using different MR contrast agents and to evaluate their potential role in the diagnosis and characterization of focal nodular hyperplasia., Materials and Methods: Contrast-enhanced MR images of 45 patients with 85 focal nodular hyperplasia lesions were retrospectively reviewed. In these patients, sonographic findings were nonspecific (n = 37), or CT features were inconclusive (n = 8). Non-liver specific gadolinium chelates were used in 18 patients (48 lesions) suspected of having either focal nodular hyperplasia or hemangioma. The following liver-specific agents were used in patients with suspected focal nodular hyperplasia or metastases: mangafodipir trisodium, 30 patients (55 lesions); ferumoxides, six patients (16 lesions); and SHU 555 A, six patients (six lesions). Individual lesions were quantified by signal intensity and assessed qualitatively by homogeneity, contrast enhancement, and presence of a central scar., Results: At unenhanced MR imaging, the triad of homogeneity, isointensity, and central scar was found in 22% of the focal nodular hyperplasia lesions. On mangafodipir trisodium-enhanced T1-weighted images, all focal nodular hyperplasia lesions showed contrast uptake: in 64% of the lesions, uptake was equal to parenchyma; 25%, greater than the parenchyma; and 11%, less than the parenchyma. On iron oxide-enhanced T2-weighted images, all focal nodular hyperplasia lesions showed uptake of the contrast agent, but contrast uptake in the lesions was less than in the surrounding parenchyma. Dynamic gadolinium chelate-enhanced MR imaging showed early and vigorous enhancement of focal nodular hyperplasia lesions with rapid washout in 88%. Atypical imaging features of the lesions included hyperintensity on T1-weighted images, necrosis and hemorrhage, and inhomogeneous or only minimal contrast uptake., Conclusion: For patients in whom the diagnosis of focal nodular hyperplasia cannot be established on unenhanced or gadolinium-enhanced MR imaging, homogeneous uptake of liver-specific contrast agent with better delineation of central scar may help to make a confident diagnosis of focal nodular hyperplasia.

Rationale and Objectives: To compare the diagnostic efficacy of a standard dose of MRI contrast agent in the evaluation of primary brain tumors and metastases using a high-field 3 tesla MR unit versus a 1.5 tesla MR unit., Methods: Sixteen patients with brain tumors were examined at both field strengths using identical axial T1-SE protocols pre- and postcontrast (0.1 mmol/kg gadolinium), and postcontrast coronal 3D GRE with magnetization preparation (MP-RAGE), which was adjusted separately for each field strength. Evaluation of the images was performed quantitatively and, in the case of T1-SE images, also by visual assessment., Results: Tumor-to-brain-contrast after gadolinium administration using statistical evaluation of MP-RAGE scans was significantly higher at 3 tesla (97.5) than at 1.5 tesla (46.3). The same was true for T1-SE sequences (93.0 vs. 72.1). Signal enhancement of the lesions in T1-SE sequences was not significantly different between both field strengths., Conclusions: Administration of a gadolinium contrast agent produces higher contrast between tumor and normal brain at 3 tesla than at 1.5 tesla.

The purpose of this study was to compare the diagnostic sensitivity of unenhanced magnetic resonance (MR) imaging, and MR imaging with a new superparamagnetic iron oxide (SPIO)-enhanced contrast agent (SHU 555 A) with biphasic helical computed tomography during arterial portography (CTAP) in patients with focal liver lesions. Eighteen patients with a total of 91 (78 malignant, 13 benign) proven liver lesions underwent unenhanced short tau inversion recovery (STIR), T2-weighted (T2-w) TSE, and SHU 555 A-enhanced T2-w turbo spin-echo (TSE) MR imaging and biphasic helical CTAP. The standard of reference was histopathologic analysis of resected specimens in 59 lesions, intraoperative ultrasound with biopsy in 20 lesions, and CT-guided biopsy and follow-up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion involvement in liver segments. There were 68 lesions detected on unenhanced T2-w TSE, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesions were detected, for a sensitivity of 84%, and with SHU 555 A-enhanced MRI, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesions, for a sensitivity of 97%. The accuracy for unenhanced T2-w TSE was 98%, for STIR 99%, for enhanced-MRI 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A-enhanced MRI and 95% for CTAP. SHU 555 A-enhanced MRI was superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false-positive results on SHU 555 A-enhanced MRI, the specificity and accuracy of enhanced MRI were higher than those of CTAP, but the difference was not statistically significant (P = 0.134)., (Copyright 2000 Wiley-Liss, Inc.)

ObjectivesThe 9th International Forum for Liver Magnetic Resonance Imaging (MRI) was held in Singapore in September 2019, bringing together radiologists and allied specialists to discuss the latest developments in and formulate consensus statements for liver MRI, including the applications of gadoxetic acid-enhanced imaging.MethodsAs at previous Liver Forums, the meeting was held over 2 days. Presentations by the faculty on days 1 and 2 and breakout group discussions on day 1 were followed by delegate voting on consensus statements presented on day 2. Presentations and discussions centered on two main meeting themes relating to the use of gadoxetic acid-enhanced MRI in primary liver cancer and metastatic liver disease.Results and conclusionsGadoxetic acid-enhanced MRI offers the ability to monitor response to systemic therapy and to assist in pre-surgical/pre-interventional planning in liver metastases. In hepatocellular carcinoma, gadoxetic acid-enhanced MRI provides precise staging information for accurate treatment decision-making and follow-up post therapy. Gadoxetic acid-enhanced MRI also has potential, currently investigational, indications for the functional assessment of the liver and the biliary system. Additional voting sessions at the Liver Forum debated the role of multidisciplinary care in the management of patients with liver disease, evidence to support the use of abbreviated imaging protocols, and the importance of standardizing nomenclature in international guidelines in order to increase the sharing of scientific data and improve the communication between centers.Key points• Gadoxetic acid-enhanced MRI is the preferred imaging method for pre-surgical or pre-interventional planning for liver metastases after systemic therapy. • Gadoxetic acid-enhanced MRI provides accurate staging of HCC before and after treatment with locoregional/biologic therapies. • Abbreviated protocols for gadoxetic acid-enhanced MRI offer potential time and cost savings, but more evidence is necessary. The use of gadoxetic acid-enhanced MRI for the assessment of liver and biliary function is under active investigation.

Hepatocellular adenomas (HCA) are acquired focal liver lesions, that occur mainly in young-to-middle-aged women who are on long-term estrogen-containing contraceptives or young men after prolonged use of anabolic steroids. Furthermore, distinct underlying diseases, such as obesity, metabolic dysfunction-associated steatotic liver disease, glycogen storage disease, etc. are considered risk factors. The 2017 Bordeaux classification, in particular Nault et al, divided HCAs into eight subtypes according to their pheno- and genotypic characteristics. This includes HCAs with hepatocyte-nuclear-factor (HNF1-alpha mutation), HCAs with β-catenin mutation, and HCAs without either of these genetic mutations, which are further subdivided into HCAs with and without inflammatory cells. HCAs should no longer be classified as purely benign without histologic workup since three of the eight subtypes are considered high-risk lesions, requiring adequate management: malignant transformation of the pure (ßex3-HCA) and mixed inflammatory/β-catenin exon 3 (ßex3-IHCA) adenomas, as well as potential bleeding of the sonic hedgehog HCA and pure (ßex7/8-HCA) and mixed inflammatory/β-catenin exon 7/8 (ßex7/8-IHCA). Elective surgery is recommended for any HCA in a male, or for any HCA exceeding 5 cm. Although MRI can classify up to 80% of adenomas, if findings are equivocal, biopsy remains the reference standard for adenoma subtype. [ABSTRACT FROM AUTHOR]

ObjectivesTo examine inter- and intra-observer agreement for four simple hepatobiliary phase (HBP)-based scores on gadoxetic acid (GA)-enhanced MRI and their correlation with liver function in patients with mixed chronic liver disease (CLD).MethodsThis single-center, retrospective study included 287 patients (62% male, 38% female, mean age 53.5 ± 13.7 years) with mixed CLD (20.9% hepatitis C, 19.2% alcoholic liver disease, 8% hepatitis B) who underwent GA-enhanced MRI of the liver for clinical care between 2010 and 2015. Relative liver enhancement (RLE), contrast uptake index (CUI), hepatic uptake index (HUI), and liver-to-spleen contrast index (LSI) were calculated by two radiologists independently using unenhanced and GA-enhanced HPB (obtained 20 min after GA administration) images; 50 patients selected at random were reviewed twice by one reader to assess intra-observer reliability. Agreement was assessed by intraclass correlation coefficient (ICC). The albumin-bilirubin (ALBI) score, the model of end-stage liver disease (MELD), and the Child-Turcotte-Pugh (CTP) score were calculated as standards of reference for hepatic function.ResultsIntra-observer ICCs ranged from 0.814 (0.668-0.896) for CUI to 0.969 (0.945-0.983) for RLE. Inter-observer ICCs ranged from 0.777 (0.605-0.874) for HUI to 0.979 (0.963-0.988) for RLE. All HBP-based scores correlated significantly (all p

ObjectivesLiver-specific MRI is a fast-growing field, with technological and protocol advancements providing more robust imaging and allowing a greater depth of information per examination. This article reports the evidence for, and expert thinking on, current challenges in liver-specific MRI, as discussed at the 7th International Forum for Liver MRI, which was held in Shanghai, China, in October 2013.MethodsTopics discussed included the role of gadoxetic acid-enhanced MRI in the differentiation of focal nodular hyperplasia from hepatocellular adenoma and small hepatocellular carcinoma (HCC) from small intrahepatic cholangiocarcinoma (in patients with chronic liver disease), the differentiation of low-grade dysplastic nodule (DN) from pre-malignant high-grade DN and early HCC, and treatment planning and assessment of treatment response for patients with HCC and colorectal liver metastasis. Optimization of the gadoxetic acid-enhanced MRI protocol to gain robust arterial and hepatobiliary phase images was also discussed.Results and conclusionsGadoxetic acid-enhanced MRI demonstrates added value for the detection and characterization of focal liver lesions and shows promise in a number of new indications, including regional liver functional assessment and patient monitoring after therapy; however, more data are needed in some areas, and further developments are needed to translate cutting-edge techniques into clinical practice.Key pointsLiver-specific MRI is a fast-growing field, with many technological and protocol advancements. Gadoxetic acid-enhanced MRI demonstrates value for detecting and characterizing focal liver lesions. Gadoxetic acid-enhanced MRI shows promise in regional functional assessment and patient monitoring. Further developments are needed to translate cutting-edge techniques into clinical practice.

Objectives: To investigate the effect of saline-diluted gadoxetic acid, done for arterial-phase (AP) artifact reduction, on signal intensity (SI), and hence focal lesion conspicuity on MR imaging. Methods: We retrospectively examined 112 patients who each had at least two serial gadoxetic acid–enhanced liver MRIs performed at 1 ml/s, first with non-diluted (ND), then with 1:1 saline-diluted (D) contrast. Two blinded readers independently analyzed the artifacts and graded dynamic images using a 5-point scale. The absolute SI of liver parenchyma, focal liver lesions (if present), aorta, and portal vein at the level of the celiac trunk and the SI of the paraspinal muscle were measured in all phases. The signal-to-norm (SINorm) of the vascular structures, hepatic parenchyma and focal lesions, and the contrast-to-norm (CNorm) of focal liver lesions were calculated. Results: AP artifacts were significantly reduced with dilution. Mean absolute contrast-enhanced liver SI was significantly higher on the D exams compared to the ND exams. Likewise, SINorm of liver parenchyma was significantly higher in all contrast-enhanced phases except transitional phase on the D exams. SINorm values in the AP for the aorta and in the PVP for portal vein were significantly higher on the diluted exams. The CNorm was not significantly different between ND and D exams for lesions in any imaging phase. The interclass correlation coefficient was excellent (0.89). Conclusion: Gadoxetic acid dilution injected at 1ml/s produces images with significantly fewer AP artifacts but no significant loss in SINorm or CNorm compared to standard non-diluted images. Key Points: • Diluted gadoxetic acid at slow injection (1 ml/s) yielded images with higher SINormof the liver parenchyma and preservedCNormfor focal liver lesions. • Gadoxetic acid–enhanced MRI injected at 1 ml/s is associated with arterial-phase (AP) artifacts in 31% of exams, which maydegrade image quality and limits focal liver lesion detection. • Saline dilution of gadoxetic acid 1:1 combined with a slow injection rate of 1 ml/s significantly reduced AP artifacts from 31 to 9% and non-diagnostic AP artifacts from 16 to 1%. [ABSTRACT FROM AUTHOR]