Underwent Liver MRI Research Articles

T2 Values for Diagnosing Acute-on-Chronic Liver Failure in Hepatitis B Patients.

The aim of this study was to investigate the value of hepatic T2 imaging for the evaluation of chronic hepatitis-B-related acute-on-chronic liver failure (HBV-ACLF). Three groups of patients underwent liver MRI utilising m-GRASE sequence (multi-echo gradient and spin echo): HBV-ACLF patients (n = 28), chronic hepatitis B patients (n = 11), and healthy control patients (n = 14). A T2 image was produced using post-processing software, and the mean T2 (relaxation time) value was calculated. Blood biochemical indices for the HBV-ACLF and Chronic Hepatitis B were obtained within 2 days pre- or post-MR scanning. The patients' T2 values, and the correlation between their biochemical indices and T2 values were analysed. A receiver operating characteristic curve was employed to evaluate the efficiency of utilising T2 values in the diagnosis of HBV-ACLF. There were significant variations in the T2 values (χ2 = 19.074, P < 0.001) among the 3 groups. The AUC of T2 values for diagnosing HBV-ACLF was 0.86 (P < 0.001), with a cut-off value of 57.73 ms. A moderately positive correlation was observed between the T2 value and the international normalised ratio, prothrombin time, and hyaluronic acid values (rs = 0.65, P < 0.001; rs = 0.67, P < 0.001; rs = 0.39, P = 0.025). A moderately negative correlation was observed between the T2 value and the prothrombin activity, albumin, and prealbumin values (rs = -0.67, P < 0.001; rs = -0.48, P = 0.004; rs = -0.37, P = 0.030). T2 values could accurately reflect liver function state, as they correlated well with certain biochemical indices, illustrating good diagnostic efficiency for diagnosing HBV-ACLF.

Water Only Sequence: An Accurate Method to Estimate Hepatic Siderosis in Patients with Thalassemia Major and Intermedia

Background: Thalassemia is a common hemoglobinopathy in Iran. Iron overload is a major complication of thalassemia, and an accurate quantification of iron deposition is the mainstay of treatment planning. The liver is the main organ for storage of iron, and quantification of hepatic siderosis is a reliable estimation of total iron overload. Objectives: The aim of this study was to determine the accuracy of chemical shift sequences (CSS), especially a water only sequence (WOS), to estimate hepatic siderosis in thalassemia patients. Patients and Methods: During a seven-month period, from May to December 2016, one hundred and two known cases of thalassemia major and intermedia underwent liver MRI. The liver iron concentration was estimated using T2* MR relaxometry. The iron signal percentage and fraction were calculated using chemical shift sequences and correlated with estimated liver iron concentration (LIC). Results: The correlation coefficient of in-phase and opposed-phase sequences was 0.566 in estimating hepatic siderosis, which was improved by employing water only sequence (0.640). The sensitivity, specificity and positive predictive value were 90.5%, 94.4% and 98.7% for the in-phase and opposed-phase sequences and 82.1%, 94.4% and 98.6% for the water only sequence, respectively. Conclusion: Chemical shift sequences, including a water only sequence, are accurate for the assessment of hepatic siderosis. Water only sequences can effectively minimize the confounding effect of fatty liver.

A proposal for a useful algorithm to diagnose small hepatocellular carcinoma on MRI.

To assess MRI features for the diagnosis of small hepatocellular carcinomas (HCCs) and especially for nodules not showing both of the typical hallmarks. Three hundred and sixty-four cirrhotic patients underwent liver MRI for 10-30 mm nodules suggestive of HCC. The diagnostic performances of MRI features [T1, T2; diffusion-weighted (DW) imaging signal, enhancement, capsule, fat content] were tested, both individually and in association with both typical hallmarks and as substitutions for one hallmark. The diagnostic reference was obtained using a multifactorial algorithm ensuring high specificity (Sp). Four hundred and ninety-three nodules were analyzed. No alternative features, associations or substitutions outperformed the typical hallmarks for the diagnosis of HCC. For 10-20 mm nodules not displaying one of the typical hallmarks, hyperintensity on DW images was the most accurate substitutive sign, providing a sensitivity of 71.4% and Sp of 75% for nodules without arterial enhancement and sensitivity = 65.2% and Sp = 66% for nodules without washout on the portal or delayed phases. A new diagnostic algorithm, including typical hallmarks as a first step then the best-performing substitutive signs (capsule presence or DW hyperintensity) in combination with the nonmissing typical hallmark as a second step, enabled the correct classification of 77.7% of all nodules, regardless of size. Using MRI, the typical hallmarks remain the best criteria for the diagnosis of small HCCs. However, by incorporating other MRI features, it is possible to build a simple algorithm enabling the noninvasive diagnosis of HCCs displaying both or only one of the typical hallmarks.

Combined gadoxetic acid and gadobenate dimeglumine enhanced liver MRI: a parameter optimization study.

To demonstrate the feasibility of combined delayed-phase gadoxetic acid (GA) and gadobenate dimeglumine (GD) enhanced liver MRI for improved detection of liver metastases, and to optimize contrast agent dose, timing, and flip angle (FA). Fourteen healthy volunteers underwent liver MRI at 3.0T at two visits during which they received two consecutive injections: 1. GA (Visit1 = 0.025mmol/kg; Visit 2 = 0.05mmol/kg) and 2. GD (both visits = 0.1mmol/kg) 20min after GA administration. Two sub-studies were performed: Experiment-1 Eight subjects underwent multi-phase breath-held 3D-fat-saturated T1-weighted spoiled gradient echo (SGRE) imaging to determine the optimal imaging window for the combined GA + GD protocol to create a homogeneously hyperintense liver and vasculature ("plain-white-liver") with maximum contrast to muscle which served as a surrogate for metastatic lesions in both experiments. Experiment-2 Six subjects underwent breath-held 3D-fat-saturated T1-weighted SGRE imaging at three different FA to determine the optimal FA for best image contrast. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated. Experiment-1 The combined GA + GD protocol created a homogeneously hyperintense liver and vasculature with maximum CNR liver/muscle at approximately 60-120s after automatic GD-bolus detection. Experiment-2 Flip angles between 25° and 35° at a dose of 0.025mmol/kg GA provided the best combination that minimized liver/vasculature CNR, while maximizing liver/muscle CNR. CNR performance to achieve a "plain-white-liver" was superior with 0.025mmol/kg GA compared to 0.05mmol/kg. Combined GA + GD enhanced T1-weighted MRI is feasible to achieve a homogeneously "plain-white-liver". Future studies need to confirm that this protocol can improve sensitivity of liver lesion detection in patients with metastatic liver disease.

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

PurposeTo conduct an intraindividual comparison of the enhancement pattern of hepatocellular adenoma (HCA) on dynamic MRI study obtained following the injection of Gadoxetic acid (Gd-EOB-DTPA) and other gadolinium-based contrast agents (GBCAs). MethodThis is a retrospective, Institutional Review Board-approved study conducted in a single institution. A search of medical records between 2008 and 2017 revealed 17 patients (all females) with at least one pathologically-proven HCA who underwent liver MRI with Gd-EOB-DTPA and another GBCA within 1 year. Enhancement of each lesion on hepatic arterial (HAP), portal venous (PVP), 2 min and 4–5 minutes phases was subjectively evaluated by two abdominal radiologists. Lesions were categorized as hyper-, iso- or hypointense compared to the surrounding liver parenchyma. The presence of a peripheral pseudocapsule was also recorded. The differences in lesion enhancement were assessed using the McNemar Test. A p-value <0.05 was considered statistically significant. ResultsThe final population included 35 HCAs (83% inflammatory subtype). There was no significant difference in lesion size (P = 0.708) and enhancement on HAP (P = 0.625) or PVP (P = 0.125). HCAs showed more frequently hypointensity on 2 min (13/35 vs. 1/35, P < 0.001) and 4–5 minutes (P < 0.001) images obtained after injection of Gd-EOB-DTPA compared to those obtained after other GBCAs. A pseudocapsule was more frequently noted after administration of Gd-EOB-DTPA (13/35 vs 1/35, P = 0.002). ConclusionsEnhancement pattern of HCA differs significantly after the injection of Gd-EOB-DTPA compared to other GBCAs. Lesion hypointensity on 2 min and 4–5 minutes images is more frequent when using Gd-EOB-DTPA.

Value of diffusion-weighted imaging in the evaluation of therapeutic effect of cyber knife on hepatocellular carcinoma

Objective To investigate the value of DWI in the evaluation of the therapeutic effect of cyber knife in the treatment of hepatocellular carcinoma. Methods Ninety patients who were clinically diagnosed with hepatocellular carcinoma (95 lesions) in the 5th Medical Center of General Hospital of PLA from February 2011 to December 2013 were retrospectively analyzed. All 90 patients underwent pre-treatment dynamic contrast-enhanced MRI scans of liver. Fourty six of them underwent liver MRI scan 3 months after treatment with cyber knife, and 49 patients underwent liver MRI scans 6 months after treatment. According to the evaluation criteria of solid tumor effect, complete necrosis tumor lesions and postoperative residual active lesions were determined. The ADC values of residual active tissue lesion, necrosis lesion in tumor and normal liver were measured. Paired sample t test was used to compare the difference of ADC values of tumor necrosis lesions and normal liver tissues between 3 and 6 months after treatment and before treatment, and ROC was used to evaluate the efficacy of ADC values in predicting complete tissue necrosis after treatment. Results In the 95 lesions, 91 lesions were completely necrotic, and active tissues were found in 4 lesions after treatment. There were statistically significant differences in the ADC values of the lesions at 3 and 6 months after treatment and before treatment (P 0.05). The area under the ROC of using ADC value to predict the complete necrosis after treatment with cyber knife was 0.767, and the ADC value was 1.23×10-3 mm2/s as the diagnostic cutoff value. The sensitivity and specificity of the diagnosis were 76.5% and 70.6%, respectively. Conclusion ADC values can distinguish the necrotic component from the active component of hepatocellular carcinoma after treatment, and can be used to evaluate the therapeutic effect of cyber knife in hepatocellular carcinoma. Key words: Liver neoplasms; Magnetic resonance imaging; Cyber knife

Quantitative Assessment of Liver Function by Using Gadoxetic Acid-enhanced MRI: Hepatocyte Uptake Ratio.

Purpose To determine whether hepatocyte uptake ratios derived at gadoxetic acid-enhanced MRI correlate with quantitative measures of liver function and can help to identify contraindication to major hepatectomy. Materials and Methods Between August 2016 and October 2016, 50 study participants with chronic liver disease or cirrhosis underwent liver MRI at 3.0 T including T1 mapping and elastography. Liver function was quantitatively assessed by using the indocyanine green retention test (ICG R15). T1 maps were obtained by using the Look-Locker sequence before and 10 minutes after gadoxetic acid administration (0.025 mmol/kg). The relationship between ICG R15 and the following MRI parameters was evaluated: pre- and postcontrast T1 values of the liver, hepatocyte uptake ratio representing the amount of contrast media solely taken into hepatocytes, liver volume, and degree of enhancement at the common bile duct. Diagnostic performance of the hepatocyte uptake ratio to identify patients with ICG R15 greater than 20% (ie, contraindication to hepatectomy) was compared with other parameters by using areas under the receiver operating characteristic curve. Results Hepatocyte uptake ratio showed a negative correlation with ICG R15 r of -0.78 (P < .001). In participants with chronic liver disease or Child-Pugh class A, those with ICG R15 of 20% or less showed higher hepatocyte uptake ratio than those with ICG R15 greater than 20% (P < .001). Hepatocyte uptake ratios demonstrated better performance for helping to detect ICG R15 greater than 20% than did liver volume (area under the curve, 0.96 vs 0.70; P = .01). Conclusion Hepatocyte uptake ratios are negatively correlated with liver function as measured by indocyanine green retention test and provide acceptable diagnostic performance for helping to identify participants who have contraindications to major hepatectomy. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Reeder in this issue.

Estimation of hepatic fat fraction using modified Dixon magnetic resonance imaging techniques: effect of liver cirrhosis

PurposeTo evaluate modified Dixon MRI techniques in hepatic fat estimation and to assess the effect of cirrhosis. Methods235 patients who underwent liver MRI were included. Correlation between modified Dixon techniques with MRS was assessed. Accuracy of MR techniques in hepatic fat estimation was calculated, and the result was compared between patients with/without liver cirrhosis. ResultsCorrelation between modified Dixon and MRS was better in group without liver cirrhosis, and accuracy of modified Dixon method was higher in group without liver cirrhosis. ConclusionsModified Dixon techniques estimate hepatic fat fraction noninvasively, but the result can be influenced by the presence of liver cirrhosis.

Feasibility of self-gated isotropic radial late-phase MR imaging of the liver.

To evaluate feasibility of a 3D-isotropic self-gated radial volumetric interpolated breath-hold examination (VIBE) for late-phase MRI of the liver. 70 patients were included and underwent liver MRI at 1.5T. Depending on the diagnosis, either Gd-EOB-DTPA (35 patients) or gadobutrol (35 patients) were administered. During late (gadobutrol) or hepatocyte-specific phase (Gd-EOB-DTPA), a radial prototype sequence was acquired and reconstructed using (1) self-gating with 40% acceptance (rVIBE40); (2) with 100% acceptance of the data (rVIBE100) and compared to Cartesian VIBE (cVIBE). Images were assessed qualitatively (image quality, lesion conspicuity, artefacts; 5-point Likert-scale: 5 = excellent; two independent readers) and quantitatively (coefficient-of-variation (CV); contrast-ratio) in axial and coronal reformations. In eight cases only rVIBE provided diagnostic image quality. Image quality of rVIBE40 was rated significantly superior (p < 0.05) in Gd-EOB-DTPA-enhanced and coronal reformatted examinations as compared to cVIBE. Lesion conspicuity was significantly improved (p < 0.05) in coronal reformatted Gd-EOB-DTPA-enhanced rVIBE40 in comparison to cVIBE. CV was higher in rVIBE40 as compared to rVIBE100/cVIBE (p < 0.01). Gadobutrol-enhanced rVIBE40 and cVIBE showed higher contrast-ratios than rVIBE100 (p < 0.001), whereas no differences were found in Gd-EOB-DTPA-enhanced examinations. Self-gated 3D-isotropic rVIBE provides significantly superior image quality compared to cVIBE, especially in multiplanar reformatted and Gd-EOB-DTPA-enhanced examinations. • Radial VIBE acquisition reduces motion artefacts. • Gd-EOB-DTPA-enhanced scans provide improved image quality. • Non-diagnostic liver MRI examinations may be reduced by radial k-spaces sampling.

Liver steatosis assessed by preoperative MRI: An independent risk factor for severe complications after major hepatic resection

Steatosis assessed by histology is commonly considered to be a significant risk factor for liver surgery. MRI is considered as the new gold standard for noninvasive liver fat quantification. The purpose was to assess whether liver steatosis determined by preoperative MRI is an independent risk factor of complications after major liver resection. All patients who underwent liver MRI before major liver resection in our institution between January 2001 and December 2011 were included in this retrospective study. The liver fat fraction (LFF) was assessed on in- and opposed-phase T1-weighted dual echo gradient echo MRI and steatosis was defined as a MRI LFF of ≥ 5%. The association between steatosis and postoperative complications (Clavien-Dindo classification, ascites > 500 mL at day 5, 50-50 criteria, fistula/collection, blood liver test alterations, pulmonary complications, nonpulmonary complications, >1 complication, duration of stay in the intensive care unit, duration of hospital stay, and death) was assessed by multivariate analysis using the appropriate model. A MRI LFF of ≥ 5% was associated with severe postoperative complications (Clavien-Dindo score ≥ IIIa; P = .04), more pulmonary complications (P = .02), and longer duration of hospital stay (P = .02) on the multivariate model adjusted for confounding factors. The postoperative aminotransferase levels were higher in patients with a MRI LFF of ≥ 5%, than in other patients (P = .0008). Liver steatosis assessed by routine preoperative MRI is shown to be an independent risk factor of severe postoperative complications after major liver resection.

MRI Findings and Prediction of Time to Progression of Patients with Hepatocellular Carcinoma Treated with Drug-eluting Bead Transcatheter Arterial Chemoembolization.

The purpose of this study was to investigate the utility of MRI findings after drug-eluting beads (DEB) - transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma in predicting time to progression (TTP). This study included 48 patients with 60 lesions who underwent liver MRI within 3 months after DEB-TACE. MRI was assessed for arterial enhancement pattern, late washout, arterioportal shunt, signal intensity on T2-weighted image, intratumoral septa, enhancing tissue on subtraction images, and treatment response. Cox-regression analysis was performed to identify independent factors to predict TTP. TTP was calculated using the Kaplan-Meier method with the log-rank test. Per lesion, 30 achieved complete remission, 22 had a partial response, and the remaining 8 lesions displayed stable disease on MRI. Arterial enhancement pattern, washout and enhancing tissue on subtraction images from MRI were associated with viable tumor on the last follow-up computerized tomography. Arterial enhancement, washout and enhancing tissue on subtraction images were significant predictors of TTP, but only enhancing tissue on subtraction images remained a significant predictor of TTP (P=0.018) in the multivariate analysis. TTP was longer in the group without enhancing tissue on subtraction images compared to the group with enhancing tissue (601 days vs. 287 days, P<0.001). Enhancing tissue on subtraction images from MRI after DEB-TACE is predictive for longer TTP.

Imaging of Body Iron Stores in Transfusion-Dependent Patients By Liver Dual- Energy CT

[Background] Chronic red blood cell transfusions, leading to iron overload, cause hepatic, cardiac, and endocrine dysfunction. It is very important to monitor body iron stores and to start optimal iron chelation therapy. Serum ferritin, which is widely used as a surrogate marker of body iron stores, elevate under inflammation or liver injury. Therefore, reliable techniques to evaluate body iron stores are needed. The liver iron concentration (LIC) is thought to be an indicator of total body iron stores and measurement of the T2* value by MRI has been a standard noninvasive technique to evaluate LIC. It should be worthwhile using CT, which is lower cost and widely applied in clinical setting. Dual-energy CT (DECT) is a technique to obtain additional information regarding tissue composition compared with what single-energy CT can provide. This technique is based on the fact that substances show different densities by two different energies. However, the role of DECT in monitoring LIC remains to be clarified. We examined whether a DECT could be a new technique for the measurement of LIC.[Patients and Methods] Eight transfusion-dependent patients underwent DECT. Patient 1 was a 54-year-old male with MDS (RCMD-RS). He received 66 U red blood cell transfusions in our hospital, and depended on transfusion in another hospital, but the total doses were not available. Patient 2 was a 37-year-old male with AML in 2nd relapse. His total red blood cell transfusions were 54 U. Patient 3 was a 66-year-old female with AML with MRC in 1st CR. She received 37 U red blood cell transfusions in our hospital, and depended on transfusion in another hospital, but total doses were not available. Patient 4 was a 47-year-old female who had received renal transplantation for chronic renal failure. She received 12 U red blood cell transfusions in our hospital, and had a long history of transfusion dependence in another hospital, but total doses were not available. Patient 5 was a 57-year-old male with MDS (RCMD). His total red blood cell transfusions were 148 U, and he received iron chelation therapy. Patient 6 was a 65-year-old male with AML with MRC. His total red blood cell transfusions were 82 U, and he received iron chelation therapy. Patient 7 was a 47-year-old male with AML in 3rd CR. He received 28 U red blood cell transfusions in our hospital, and depended on transfusion in another hospital, but total doses were not available. Patient 8 was a 52-year-old female with AA. Her total blood cell transfusions were 92 U.[Results] All patients were examined for serum ferritin and patients 1, 3, 4, 6, 7, and 8 also underwent liver MRI. Serum ferritin levels of patients 1, 3, 4, 6, 7, and 8 were 961, 2168, 7875, 795, 1921, and 5104 ng/ml, respectively. These patients showed hypointensity on MRI T2*-weighted images, and also showed liver iron deposition by DECT. Serum ferritin of patient 5 was 4042 ng/ml, and he showed liver iron deposition by DECT. Serum ferritin of patient 2 was 6113 ng/ml, and he did not show liver iron deposition by DECT.[Conclusion] Our results suggest that liver DECT could visualize liver iron deposition of transfusion-dependent patients and could be a new technique for the measurement of LIC instead of MRI. DisclosuresNo relevant conflicts of interest to declare.

Role of diffusion-weighted imaging, apparent diffusion coefficient and correlation with hepatobiliary phase findings in the differentiation of hepatocellular carcinoma from dysplastic nodules in cirrhotic liver.

To investigate the utility of diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) and the correlation with hepatobiliary phase (delayed phase imaging, DPI) findings in the differentiation of cirrhotic hepatocellular nodules. Forty-three patients with 53 pathology-proven nodules (29 hepatocellular carcinomas (HCCs), 13 high-grade (HGDNs) and 11 low-grade dysplastic nodules (LGDNs); mean size 2.17 cm, range 1-4 cm), who underwent liver MRI with DWI and DPI sequences, were retrospectively reviewed. Lesions were classified as hypointense, isointense, or hyperintense relative to the adjacent liver parenchyma. ADC of each nodule, of the surrounding parenchyma, and lesion-to-liver ratio were calculated. Hyperintensity versus iso/hypointensity on DWI, hypointensity versus iso/hyperintensity on DPI, and the mean lesion-to-liver ratio showed a statistically significant difference both between HCCs versus DNs and between "HCCs + HGDNs" versus LGDNs (p < 0.05); sensitivity, specificity, and accuracy for the diagnosis of "HCCs + HGDNs" were 96.8 %, 100 %, 97.4 % respectively when combining hyperintensity on DWI and hypointensity on DPI, and 90.9 %, 81.0 %, 83.6 % respectively when lesion-to-liver ratio was <0.95. Hyperintensity on DWI, especially in association with hypointensity on DPI, and low lesion-to-liver ratios should raise the suspicion of HCC, or at least of HGDN, thus helping the characterization of atypically enhancing lesions. • Usefulness of DWI and ADC is shown in differential diagnosis of cirrhotic nodules. • Correlation of DWI with DPI improves differential diagnosis of cirrhotic nodules. • Characterization of atypically enhancing lesions becomes more confident.

High-resolution T1-weighted gradient echo imaging for liver MRI using parallel imaging at high-acceleration factors

To determine whether application of a high-acceleration parallel acquisition can provide three-dimensional (3D)-fat-suppressed T1-weighted gradient-recalled-echo (T1W-GRE) imaging at 3T for liver MR imaging. This retrospective study was approved by our institutional review board. Seventy patients underwent liver MRI at a 3T scanner. After administration of a standard dose of Gadoxetic acid for 20 min, 3D-T1W-GRE images were obtained twice using sensitivity encoding with acceleration factors (AFs) 2.6 [332 × 298 matrix, 3-mm slice thickness (ST)] and 4 (380 × 320 matrix, 1.5-mm ST). The image qualities of the two image sets were graded using a five-point scale. The high-resolution (HR) 3D-T1W-GRE image sets were obtained with an AF 4 within a single breath-hold (18.5 s). It showed a better anatomic depiction than conventional 3D-T1W-GRE image sets with an AF 2.6 (p < 0.05). Although the image noise was higher on the HR image sets (p < 0.05), the HR image sets showed better lesion conspicuity and overall image quality than the conventional image sets (p < 0.05). With the use of high AFs, HR 3D-T1W-GRE imaging was demonstrated to be clinically more feasible and advantageous than the conventional 3D-T1W-GRE.

Biologic Factors Affecting HCC Conspicuity in Hepatobiliary Phase Imaging With Liver-Specific Contrast Agents

The purpose of this study was to evaluate factors influencing hepatic enhancement and the conspicuity of hepatocellular carcinoma (HCC) on gadobenate dimeglu-mine- and gadoxetate disodium-enhanced hepatobiliary phase MR images. Patients with chronic liver disease who underwent liver MRI with gadobenate dimeglumine (n = 93) or gadoxetate disodium (n = 92) were included in this study. The degree of hepatic enhancement on 1-hour and 3-hour delayed phase gadobenate dimeglumine-enhanced and 20-minute delayed phase gadoxetate disodium-enhanced hepatobiliary phase images were evaluated with quantitative and visual indexes. The conspicuity of 40 HCCs in the gadobenate dimeglumine group and 38 HCCs in the gadoxetate disodium group were graded on a 5-point scale. Correlation between hepatic enhancement indexes and clinical factors (age, body weight, serum bilirubin concentration, model for end-stage liver disease score, Child-Pugh class, and renal function stage) and association between the conspicuity of HCCs and clinical factors, lesion diameter, and hepatic enhancement indexes were evaluated. In the gadobenate dimeglumine group, the visual index of hepatic enhancement independently correlated with Child-Pugh class on both 1- and 3-hour delayed images (p < 0.001) and with renal function stage only on 3-hour delayed images (p ≤ 0.031). In the gadoxetate disodium group, both quantitative and visual indexes of hepatic enhancement independently correlated with Child-Pugh class (p ≤ 0.019). The conspicuity of HCCs independently correlated with Child-Pugh class and lesion diameter on 3-hour delayed gadobenate dimeglumine-enhanced images (p ≤ 0.031) and on gadoxetate disodium-enhanced images (p = 0.033) and significantly correlated with the visual index of hepatic enhancement on both gadobenate dimeglumine- and gadoxetate disodium-enhanced images (p ≤ 0.001). Liver enhancement and conspicuity of HCC are significantly affected by Child-Pugh class on both gadobenate dimeglumine- and gadoxetate disodium-enhanced hepatobiliary phase MR images.

Lesion detection and assessment of extrahepatic findings in abdominal MRI using hepatocyte specific contrast agents – comparison of Gd-EOB-DTPA and Gd-BOPTA

BackgroundTo evaluate the contrast agent performance of Gd-EOB-DTPA and Gd-BOPTA for detection and assessment of extrahepatic findings, semi-quantitatively and qualitatively.Methods13 patients with 19 extrahepatic lesions underwent liver MRI with Gd-EOB-DTPA and Gd-BOPTA. Quantitative and relative SNR measurements were performed in each dataset in the arterial and portalvenous phase within the extrahepatic lesion, aorta, inferior vena cava, portal vein, spleen, pancreas and renal cortex. Further, relative CNR measurements were performed. Three readers assessed contrast quality using a five-point scale and choosing the preferred image dataset. Statistical analysis consisted of a Student’s t-test with p < 0.05 deemed significant, a weighted kappa statistic for assessment of interobserver variability and an ROC analysis.ResultsMean SNR after injection of Gd-BOPTA was significantly higher compared with Gd-EOB-DTPA for all measurements (p < 0.05). Mean relative SNR was also higher for Gd-BOPTA, but without being statistically significant. There was no significant difference in relative CNR. Interobserver agreement for selection of image preference was moderate (mean weighted kappa 0.485). The area under the curve for the ROC-analysis regarding contrast agent performance was 0.464.ConclusionEven though mean SNR is significantly higher after injection of Gd-BOPTA compared with Gd-EOB-DTPA, there is no significant difference in relative CNR with extrahepatic lesions being assessed equally well. Visual impression may differ after injection of Gd-EOB-DTPA, but does not influence image interpretation. Extrahepatic findings can be assessed similarly to MRI after injection of Gd-BOPTA.

Assessment of liver tumor response by high-field (3 T) MRI after radiofrequency ablation: Short- and mid-term evolution of diffusion parameters within the ablation zone

PurposeTo compare the apparent diffusion coefficient (ADC) values of malignant liver lesions on diffusion-weighted MRI (DWI) before and after successful radiofrequency ablation (RF ablation). Materials and methodsThirty-two patients with 43 malignant liver lesions (23/20: metastases/hepatocellular carcinomas (HCC)) underwent liver MRI (3.0T) before (<1month) and after RF ablation (at 1, 3 and 6months) using T2-, gadolinium-enhanced T1- and DWI-weighted MR sequences. Jointly, two radiologists prospectively measured ADCs for each lesion by means of two different regions of interest (ROIs), first including the whole lesion and secondly the area with the visibly most restricted diffusion (MRDA) on ADC map. Changes of ADCs were evaluated with ANOVA and Dunnett tests. ResultsThirty-one patients were successfully treated, while one patient was excluded due to focal recurrence. In metastases (n=22), the ADC in the whole lesion and in MRDA showed an up-and-down evolution. In HCC (n=20), the evolution of ADC was more complex, but with significantly higher values (p=0.013) at 1 and 6months after RF ablation. ConclusionThe ADC values of malignant liver lesions successfully treated by RF ablation show a predictable evolution and may help radiologists to monitor tumor response after treatment.

Diffusion weighted MR imaging in patients with HCC and liver cirrhosis after administration of different gadolinium contrast agents: Is it still reliable?

Diffusion weighted imaging (DWI) is an emerging technique for abdominal MR and usually performed before intravenous contrast injection. Recent studies performed in patients with normal liver function have shown that DWI can be performed after gadolinium administration. Aim of this study was to compare DWI before and after administration of different gadolinium compounds in patients with HCC and liver cirrhosis. 15 patients with known HCC and liver cirrhosis underwent liver MRI at 1.5T (Magnetom Avanto, Siemens) including DWI on day 1 before and after administration of gadobutrol (Gadovist(®)) and on day 2 after administration of EOB-Gadolinium-DTPA (Primovist(®)). Signal to noise ratios (SNR) and contrast to noise ratios (CNR) of HCC lesions were determined for all DWI data sets. Furthermore, ADC values were compared using a Wilcoxon test. A p-value <0.05 indicated statistically significant differences. There were no statistically significant differences regarding SNR pre-contrast (mean: 48.1), after gadobutrol (mean: 47.7) or after EOB-Gadolinium-DTPA (mean: 50.0; values for b=50s/mm(2)). Similarly, no significant differences were found for CNR (average values:34.4 vs. 32.3 vs. 30.7; b=50s/mm(2)) nor for ADC-values (mean: 1.5 vs. 1.4 vs. 1.5×10(-3)mm(2)/s) of HCC. There is no significant difference regarding DWI in patients with cirrhosis before and after contrast injection. Hence, it is reliable to run DWI after gadolinium either as an alternative for unsuccessful pre-contrast DWI or as a gap filler to spare time in EOB-Gadolinium-DTPA imaging.

New MR imaging criteria with a diffusion-weighted sequence for the diagnosis of hepatocellular carcinoma in chronic liver diseases

To propose MRI criteria with a diffusion-weighted imaging (DWI) sequence for the diagnosis of hepatocellular carcinoma (HCC). Patients, who underwent liver MRI with contrast-enhanced sequences and DWI between 2004 and 2008 and who had at least one confirmed HCC of at least 10mm, were included. Index diagnostic criteria were: (1) enhancement in the arterial-dominant phase and washout in the portal venous and/or equilibrium phases; (2) enhancement in the arterial-dominant phase and hyperintensity on DWI; (3) enhancement in the arterial-dominant phase and washout in the portal venous and/or equilibrium phases or hyperintensity on DWI. Two radiologists independently reviewed the corresponding sets of sequences (DWI alone; T1-weighted sequence before and after dynamic injection of gadolinium chelates; combined DWI-T1-weighted sequence). Inter-observer agreement and sensitivity were determined per nodule. Ninety-one patients were included (109 HCCs). The sensitivity of conventional MRI criteria for the diagnosis of HCC was 59.6% for both radiologists. The sensitivity of enhancement in the arterial-dominant phase and hyperintensity on DWI was 77.1% or 76.1%, depending on the radiologist. The sensitivity of enhancement in the arterial-dominant phase and washout in the portal venous and/or equilibrium phases or hyperintensity on DWI was 84.4% or 85.3%, depending on the radiologist. The inter-observer agreement for the latter was very good (kappa coefficient 0.82). These results were consistent in HCCs smaller than 20mm. The proposed criteria, based on the characteristics of lesions after gadolinium chelate administration and hyperintensity on DWI, significantly increased the sensitivity for the diagnosis of HCC compared to conventional criteria, regardless of tumor size.

470 E-cadherin plasticity in tumor-initiating stem-like cells regulates prostate cancer cell invasion

Diffusion weighted imaging (DWI) is an emerging technique for abdominal MR and usually performed before intravenous contrast injection. Recent studies performed in patients with normal liver function have shown that DWI can be performed after gadolinium administration. Aim of this study was to compare DWI before and after administration of different gadolinium compounds in patients with HCC and liver cirrhosis.15 patients with known HCC and liver cirrhosis underwent liver MRI at 1.5 T (Magnetom Avanto, Siemens) including DWI on day 1 before and after administration of gadobutrol (Gadovist®) and on day 2 after administration of EOB-Gadolinium-DTPA (Primovist®). Signal to noise ratios (SNR) and contrast to noise ratios (CNR) of HCC lesions were determined for all DWI data sets. Furthermore, ADC values were compared using a Wilcoxon test. A p-value <0.05 indicated statistically significant differences.There were no statistically significant differences regarding SNR pre-contrast (mean: 48.1), after gadobutrol (mean: 47.7) or after EOB-Gadolinium-DTPA (mean: 50.0; values for b = 50 s/mm2). Similarly, no significant differences were found for CNR (average values:34.4 vs. 32.3 vs. 30.7; b = 50 s/mm2) nor for ADC-values (mean: 1.5 vs. 1.4 vs. 1.5 × 10−3 mm2/s) of HCC.There is no significant difference regarding DWI in patients with cirrhosis before and after contrast injection. Hence, it is reliable to run DWI after gadolinium either as an alternative for unsuccessful pre-contrast DWI or as a gap filler to spare time in EOB-Gadolinium-DTPA imaging.