Noninvasive assessment of hepatic fibrosis using gadoxetate-disodium-enhanced 3T MRI

Introduction. Gadoxetate-disodium is a liver-specific MR contrast agent absorbed by hepatocytes via organic anion transporting polypeptide 1B3 and is excreted into the biliary system by multidrug resistance-associated protein 2. It has been suggested that relative parenchymal enhancement on hepatocyte phase image is associated with hepatic function. However, it is not clear whether gadoxetate-disodium-enhanced MRI can be used as a noninvasive fibrosis marker. Thus, the purpose of our study was to evaluate the diagnostic performance of gadoxetate-disodium-enhanced MRI in predicting the hepatic fibrosis stage.Materials and methods. A total of 113 patients who had fibrosis staged according to the Batts and Ludwig score were enrolled: F0 (n = 13), F1 (n = 18), F2 (n = 15), F3 (n = 32), and F4 (n = 35). All patients underwent gadoxetate-disodium-enhanced MRI before confirmation by biopsy (n = 67) or surgery (n = 46). For quantitative analysis, the contrast enhancement index (CEI) was calculated by measuring the signal intensity (SI) in liver and paraspinal muscle using a region of interest, as follows: CEI = (liver SI/paraspinal muscle SI) 20 min hepatocyte phase image/(liver SI/paraspinal muscle SI) pre-contrast T1–weighted image. The diagnostic performance was evaluated by the ROC curve, adjusted for the prevalence of each fibrosis stage.Results. A significant negative correlation was observed between CEI and fibrosis stage (r = –0.545, P < 0.0001). The adjusted AUROC for CEI in the prediction of mild (≥ F1), moderate (≥ F2), or severe fibrosis (≥ F3) and liver cirrhosis (F4) was 0.668, 0.703, 0.73, and 0.84, respectively. In conclusion, our results demonstrate that quantitative analysis of relative hepatic enhancement using gadoxetate-disodium-enhanced MRI can predict the hepatic fibrosis stage

Application of a Perception Neuron^® System in Simulation-Based Surgical Training

While multiple studies show that simulation methods help in educating surgical trainees, few studies have focused on developing systems that help trainees to adopt the most effective body motions. This is the first study to use a Perception Neuron&#174; system to evaluate the relationship between body motions and simulation scores. Ten medical students participated in this study. All completed two standard tasks with da Vinci Skills Simulator (dVSS) and five standard tasks with thyroidectomy training model. This was repeated. Thyroidectomy training was conducted while participants wore a perception neuron. Motion capture (MC) score that indicated how long the tasks took to complete and each participant&#8217;s economy-of-motion that was used was calculated. Correlations between the three scores were assessed by Pearson&#8217;s correlation analyses. The 20 trials were categorized as low, moderate, and high overall-proficiency by summing the training model, dVSS, and MC scores. The difference between the low and high overall-proficiency trials in terms of economy-of-motion of the left or right hand was assessed by two-tailed t-test. Relative to cycle 1, the training model, dVSS, and MC scores all increased significantly in cycle 2. Three scores correlated significantly with each other. Six, eight, and six trials were classified as low, moderate, and high overall-proficiency, respectively. Low- and high-scoring trials differed significantly in terms of right (dominant) hand economy-of-motion (675.2 mm and 369.4 mm, respectively) (p = 0.043). Perception Neuron&#174; system can be applied to simulation-based training of surgical trainees. The motion analysis score is related to the traditional scoring system

Emergence of vanA Genotype Vancomycin-Resistant Enterococci with Low or Moderate Levels of Teicoplanin Resistance in Korea

In Korea, vancomycin-resistant enterococci have become important nosocomial pathogens since the late 1990s, and most vancomycin-resistant enterococcal isolates have been VanA phenotype-vanA genotype strains. In 2001, we experienced an outbreak of VanB phenotype-vanA genotype vancomycin-resistant enterococci at a university hospital. This is the first report of VanB-vanA vancomycin-resistant enterococci from humans in Korea