Prospective Comparison of Noninvasive Fibrosis Assessment to Predict Advanced Fibrosis or Cirrhosis in Asian Patients With Hepatitis C.

GOALS AND BACKGROUND: The diagnostic role of noninvasive fibrosis assessment, which can obviate liver biopsy in Asian patients with hepatitis C, remains controversial. This study aimed to evaluate the diagnostic accuracy of noninvasive fibrosis assessment to predict advanced fibrosis or cirrhosis in Asian patients with hepatitis C. STUDY: A total of 101 antiviral treatment-naive patients with hepatitis C were prospectively enrolled between March 2011 and March 2013. Liver stiffness was measured by acoustic radiation force impulse (ARFI) elastography. At the same time, liver biopsy was performed to obtain histologic data of hepatic fibrosis. Diagnostic measurements of serum fibrosis indices and ARFI imaging were compared with predicted advanced fibrosis or cirrhosis by analyzing the area under the receiver operating characteristic (AUROC) curve. RESULTS: The median age of the study population was 59 years (range, 25 to 82 y). Aspartate aminotransferase to alanine aminotransferase ratio (AAR), Fib-4, Forns index, aspartate aminotransferase to platelet ratio index (APRI), and Lok index showed significant, positive correlations with METAVIR stages (P<0.001). Fib-4 had the greatest AUROC for advanced fibrosis (≥F3) (0.864; 95% CI, 0.793-0.934), and the Lok index had the highest AUROC for predicting cirrhosis (F4) (0.847; 95% CI, 0.767-0.927). A tendency toward increasing liver stiffness existed in a graded manner across METAVIR stages (P<0.001). CONCLUSIONS: Fib-4 and Lok index were useful noninvasive fibrosis indices for predicting advanced fibrosis and cirrhosis in Asian patients with hepatitis C. In addition, ARFI elastography exhibited acceptable diagnostic performance in the assessment of hepatic fibrosis in patients with hepatitis C.

High spatial resolution, respiratory-gated, t1-weighted magnetic resonance imaging of the liver and the biliary tract during the hepatobiliary phase of gadoxetic Acid-enhanced magnetic resonance imaging.

PURPOSE: The aim of this study was to demonstrate the clinical feasibility of a recently developed navigator-gated, 3-dimensional gradient echo (3D-GRE) sequence for high-resolution, T1-weighted imaging (HR-T1WI) during the hepatobiliary phase (HBP) of gadoxetic acid-enhanced liver magnetic resonance imaging (MRI). MATERIALS AND METHODS: Eighty-seven consecutive patients who underwent gadoxetic acid-enhanced liver MRI were included in this study. To obtain HR-T1WI (acquired resolution, 1 × 1 × 2 mm), a gated 3D-GRE sequence (gated volumetric interpolated breath-hold examination [VIBE]; Siemens) with fat suppression was performed during the HBP and was then compared with standard breath-hold (BH)-GRE sequence (BH-VIBE). For the respiration gating, the phase ordering using the automatic window selection technique was used. Three readers independently scored the artifacts and the imaging quality (IQ) of both image sets and also classified BH-VIBE images into acceptable or unacceptable IQ. Noise and signal-noise ratio of the BH-VIBE and gated-VIBE sequences were compared, and image quality improvement using gated VIBE compared with BH-VIBE was determined when BH-VIBE shows unacceptable IQ. RESULTS: The gated-VIBE sequence successfully provided HR-T1WI, having diagnosable image quality in all patients except 4 patients in 1 reader (95.4%, 83/87). The gated-VIBE sequence showed relatively higher levels of noise (mean [SD], 6.04 [3.18] vs. 3.57 [0.66]) but similar signal-noise ratio (93.60 [39.47] vs. 100.05 [28.94]) compared with BH-VIBE (P = 0.15). In the qualitative analysis, the gated 3D-GRE sequence showed higher scores for depicting focal liver lesions and the sharpness of the hepatic edges (P < 0.0001) but lower subjective overall IQ than did the BH-VIBE (P < 0.01). However, in the patients showing unacceptable BH-VIBE image quality, the degree of improvement of the IQ using the gated-VIBE technique was significantly higher than that seen in the patients showing acceptable BH-VIBE image quality (P < 0.01). CONCLUSIONS: T1-weighted gated-VIBE showed technical feasibility for HR-T1WI during HBP imaging of gadoxetic acid-enhanced MRI.

Shear wave elastography in the evaluation of rejection or recurrent hepatitis after liver transplantation.

OBJECTIVES: To determine whether shear wave elastography (SWE) would be useful in evaluating the presence of rejection or recurrent hepatitis for post-liver transplantation (LT) follow-up. METHODS: This retrospective study was approved by our Institutional Review Board and informed consent was waived. Two hundred sixteen liver recipients and 37 liver donors received SWE and concurrent liver biopsy. Of the liver recipients, 142 patients underwent SWE > 4 weeks after the LT (group 1) and 74 patients underwent SWE ≤ 4 weeks after the LT (group 2). Liver stiffness (LS) was compared among groups of donor, no rejection, acute rejection and recurrent hepatitis. RESULTS: In group 1, LS was higher in patients with rejection or hepatitis than in patients without rejection or indefinite rejection (12.29 ± 8.13 kPa vs. 6.33 ± 2.10 kPa, respectively, P < 0.001). In group 2, there was no difference in LS between patients with rejection (n = 8) and those without rejection (n = 61; P > 0.05). The liver recipients without rejection or hepatitis in both groups showed significantly higher LS than the liver donors (P < 0.001). CONCLUSIONS: SWE may be used as a non-invasive complementary tool to detect rejection or recurrent hepatitis at follow-up > 4 weeks after the LT. KEY POINTS: • Shear wave ultrasound elastography may be useful at follow-up after liver transplantation • Rejection or hepatitis can be predicted >4 weeks after liver transplantation • Normal liver grafts are stiffer than normal liver.

Thermoplastic Polyurethane Elastomer-Based Gel Polymer Electrolytes for Sodium-Metal Cells with Enhanced Cycling Performance.

Sodium batteries have been recognized as a promising alternative to lithium-ion batteries. However, the liquid electrolyte used in these batteries has inherent safety problems. Polymer electrolytes have been considered as safer and more reliable electrolyte systems for rechargeable batteries. Herein, a thermoplastic polyurethane elastomer-based gel polymer electrolyte with high ionic conductivity and high elasticity was reported. It had an ambient-temperature ionic conductivity of 1.5 mS cm-1 and high stretchability, capable of withstanding 610 % strain. Coordination between Na+ ions and polymer chains increased the degree of salt dissociation in the gel polymer electrolyte compared with the liquid electrolyte. An Na/Na3 V2 (PO4 )3 cell assembled with gel polymer electrolyte exhibited good cycling performance in terms of discharge capacity, cycling stability, and rate capability, which was owing to the effective trapping ability of organic solvents in the polymer matrix and uniform flux of sodium ions through the gel polymer electrolyte.

Semi-Interpenetrating Polymer Network Composite Gel Electrolytes Employing Vinyl-Functionalized Silica for Lithium-Oxygen Batteries with Enhanced Cycling Stability.

A major challenge of lithium-oxygen batteries is to develop a stable electrolyte not only to suppress solvent evaporation and lithium dendrite growth, but also to resist the attack by superoxide anion radical formed at the positive electrode. The present study demonstrates the enhancement of cycling stability by addressing the above challenges through the use of three-dimensional semi-interpenetrating polymer network (semi-IPN) composite gel polymer electrolyte when fabricating the lithium-oxygen cell. The semi-IPN composite gel electrolyte synthesized from poly(methyl methacrylate), divinylbenzene, and vinyl-functionalized silica effectively encapsulated electrolyte solution and exhibited stable interfacial characteristics toward lithium electrodes. Matrix polymers in the semi-IPN composite gel electrolyte also retained high stability without any decomposition by superoxide anion radicals during cycling. The lithium-oxygen cell employing semi-IPN composite gel polymer electrolyte was shown to cycle with good capacity retention at 0.25 mAh cm-2. The semi-IPN composite gel electrolyte is one of the promising electrolytes for the stable lithium-oxygen battery with high energy density.

Improved Cycling Performance of Lithium-Oxygen Cells by Use of a Lithium Electrode Protected with Conductive Polymer and Aluminum Fluoride.

Lithium-oxygen batteries have attracted great attention for advanced energy storage systems because of their high specific energy. The enhancement of the interfacial stability of lithium negative electrodes is one of the many technical challenges toward high safety and long life lithium-oxygen batteries due to their high reactivity toward organic electrolytes and the lithium dendrite growth during the repeated cycling. Herein, we demonstrate that the protective layer comprising conductive polymer and AlF3 particles on lithium metal stabilized the lithium electrode by effectively reducing the reductive decomposition of the liquid electrolyte and suppressing the growth of lithium dendrite. As a result, the cycling performance of a lithium-oxygen cell assembled with a surface-modified lithium electrode was remarkably improved as compared to a cell with a pristine lithium electrode.

Staging of hepatic fibrosis: comparison of magnetic resonance elastography and shear wave elastography in the same individuals.

OBJECTIVE: To cross-validate liver stiffness (LS) measured on shear wave elastography (SWE) and on magnetic resonance elastography (MRE) in the same individuals. MATERIALS AND METHODS: We included 94 liver transplantation (LT) recipients and 114 liver donors who underwent either MRE or SWE before surgery or biopsy. We determined the technical success rates and the incidence of unreliable LS measurements (LSM) of SWE and MRE. Among the 69 patients who underwent both MRE and SWE, the median and coefficient of variation (CV) of the LSM from each examination were compared and correlated. Areas under the receiver operating characteristic curve in both examinations were calculated in order to exclude the presence of hepatic fibrosis (HF). RESULTS: The technical success rates of MRE and SWE were 96.4% and 92.2%, respectively (p = 0.17), and all of the technical failures occurred in LT recipients. SWE showed 13.1% unreliable LSM, whereas MRE showed no such case (p < 0.05). There was moderate correlation in the LSM in both examinations (r = 0.67). SWE showed a significantly larger median LSM and CV than MRE. Both examinations showed similar diagnostic performance for excluding HF (Az; 0.989, 1.000, respectively). CONCLUSION: MRE and SWE show moderate correlation in their LSMs, although SWE shows higher incidence of unreliable LSMs in cirrhotic liver.

Recent Advances in CT and MR Imaging for Evaluation of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Accurate diagnosis and assessment of disease extent are crucial for proper management of patients with HCC. Imaging plays a crucial role in early detection, accurate staging, and the planning of management strategies. A variety of imaging modalities are currently used in evaluating patients with suspected HCC; these include ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography. Among these modalities, dynamic MRI and CT are regarded as the best imaging techniques available for the noninvasive diagnosis of HCC. Recent improvements in CT and MRI technology have made noninvasive and reliable diagnostic assessment of hepatocellular nodules possible in the cirrhotic liver, and biopsy is frequently not required prior to treatment. Until now, the major challenge for radiologists in imaging cirrhosis has been the characterization of small cirrhotic nodules smaller than 2 cm in diameter. Further technological advancement will undoubtedly have a major impact on liver tumor imaging. The increased speed of data acquisition in CT and MRI has allowed improvements in both spatial and temporal resolution, which have made possible a more precise evaluation of the hemodynamics of liver nodules. Furthermore, the development of new, tissue-specific contrast agents such as gadoxetic acid has improved HCC detection on MRI. In this review, we discuss the role of CT and MRI in the diagnosis and staging of HCC, recent technological advances, and the strengths and limitations of these imaging modalities.