Wireless amplified NMR detector for improved visibility of image contrast in heterogeneous lesions

To demonstrate the capability of a wireless amplified NMR detector (WAND) to improve the visibility of lesion heterogeneity without the use of exogenous contrast agents, a cylindrically symmetric WAND was constructed to sensitively detect and simultaneously amplify MR signals emitted from adjacent tissues. Based on a two‐leg high‐pass birdcage coil design, this WAND could be activated by a pumping field aligned along the main field (B₀), without perturbing MR signal reception. Compared with an equivalent pair of external detectors, the WAND could achieve more than 10‐fold gain for immediately adjacent regions. Even for regions with 3.4 radius distance separation from the detector's cylindrical center, the WAND was at least 1.4 times more sensitive than an equivalent pair of surface arrays or at least twice as sensitive as a single‐sided external surface detector. When the WAND was inserted into a rat's rectum to observe adjacent tumors implanted beneath the mucosa, it could enhance the detection sensitivity of lesion regions, and thus enlarge the observable signal difference between heterogeneous tissues and clearly identify lesion boundaries as continuous lines in the intensity gradient profile. Hyperintense regions observable by the WAND existed due to higher levels of blood supply, which was indicated by a similar pattern of signal enhancement after contrast agent administration. By better observing the endogenous signal contrast, the endoluminal WAND could characterize lesions without the use of exogenous contrast agents, and thus reduce contrast‐induced toxicity.     

Strategies for Distance Education

Abstract

Advances in and access to technology have loosened academia's ties to the traditional classroom. In this paper we present our experiences in developing, implementing, and evaluating three approaches to distance education. The first program was delivered by interactive videoconferencing and provided multiple gerontological lessons for Extension agents gathered at two different sites in Virginia. The second program was a graduate-level course taught simultaneously at multiple sites also using interactive videoconferencing. The third program was a full-fledged Internet course whose target audience included students enrolled in a gerontology certificate program. The overall strengths of the programs included enhancing the instructors' ability to reach students in a variety of locations without leaving campus and expanding the flexibility and availability of course offerings. The weaknesses and constraints of the various approaches centered on the amount of instructor time necessary to develop and implement the instructional units, technological problems, and student involvement and motivation.     

Developing an expert panel process to refine health outcome definitions in observational data

ObjectivesDrug safety surveillance using observational data requires valid adverse event, or health outcome of interest (HOI) measurement. The objectives of this study were to develop a method to review HOI definitions in claims databases using (1) web-based digital tools to present de-identified patient data, (2) a systematic expert panel review process, and (3) a data collection process enabling analysis of concepts-of-interest that influence panelists’ determination of HOI.MethodsDe-identified patient data were presented via an interactive web-based dashboard to enable case review and determine if specific HOIs were present or absent. Criteria for determining HOIs and their severity were provided to each panelist. Using a modified Delphi method, six panelist pairs independently reviewed approximately 200 cases across each of three HOIs (acute liver injury, acute kidney injury, and acute myocardial infarction) such that panelist pairs independently reviewed the same cases. Panelists completed an assessment within the dashboard for each case that included their assessment of the presence or absence of the HOI, HOI severity (if present), and data contributing to their decision. Discrepancies within panelist pairs were resolved during a consensus process.ResultsDashboard development was iterative, focusing on data presentation and recording panelists’ assessments. Panelists reported quickly learning how to use the dashboard. The assessment module was used consistently. The dashboard was reliable, enabling an efficient review process for panelists. Modifications were made to the dashboard and review process when necessary to facilitate case review. Our methods should be applied to other health outcomes of interest to further refine the dashboard and case review process.ConclusionThe expert review process was effective and was supported by the web-based dashboard. Our methods for case review and classification can be applied to future methods for case identification in observational data sources.     

Genetic analysis of human rhinovirus species A to C detected in patients with acute respiratory infection in Kumamoto prefecture,Japan 2011–2012

We performed detailed genetic analysis of the VP4/VP2 coding region in human rhinovirus species A to C (HRV-ABC) strains detected in patients with a variety of acute respiratory infections in Kumamoto, Japan in the period 2011–12. The phylogenetic tree and evolutionary timescale were obtained by the Bayesian Markov chain Monte Carlo method. Phylogenetic analyses showed that the present HRV-A, -B, and -C strains belonged to 25, 4, and 18 genotypes, respectively. Some new genotypes were confirmed as prevalent strains of HRV-C. An ancestor of the present HRV-ABCs could be dated back to about 20,000 years ago. The present HRV-A and -C strains have wide genetic divergence (pairwise distance >0.2) with rapid evolutionary rates (around 7 × 10⁻⁴ to 4 × 10⁻³ substitutions/site/year). Over 100 sites were found to be under negative selection, while no positively selected sites were found in the analyzed region. No evidence of recombination events was found in this region of the present strains. Our results indicate that the present HRV strains have rapidly evolved and subsequently diverged over a long period into multiple genotypes.     

Supplementary values of the dosimetric parameters kNR and Em for various types of detectors in 6 and 15 MV photon fields

The present communication broadens the data base for determinations of the non-reference condition correction factor k_NR needed in high-energy photon dosimetry to accomplish the use of various detectors under non-reference conditions. Following our previous strategy of calculating semiempirical values of k_NR and correlating them with the mean photon energy E_m at the point of measurement in a large water phantom, the values of E_m are now stated for 6 and 15 MV photon radiations of accelerators with and without flattening filters, square field sizes from 1 to 30 cm side length and depths from 0 to 28 cm. The unambiguity of the k_NR-E_m correlation is again confirmed and is quantified by fitting formulae for air-filled ionization chambers, TLD detectors and Si diodes. This survey provides a practicable access to the k_NR values, particularly for the non-water equivalent detectors to be used in small-field dosimetry     

Accuracy analysis of computer-assisted surgery for femoral trochanteric fracture using a fluoroscopic navigation system: Stryker ADAPT®system

PurposeADAPT is a fluoroscopic computer-assisted surgery system which intraoperatively shows the distance from the tip of the screw to the surface of the femoral head, tip-to-head-surface distance (TSD), and the tip-apex distance (TAD) advocated by Baumgaertner et al. The study evaluated the accuracy of ADAPT.Patients and methodsA total of 55 patients operated with ADAPT between August 2016 and March 2017 were included as subjects. TSD and TAD were measured postoperatively using computed tomography (CT) and X-rays. The intraclass correlation coefficient (ICC) was checked in advance. The error was defined as the difference between postoperative and intraoperative measurement values of ADAPT. Summary statistics, root mean square errors (RMSEs), and correlations were evaluated.ResultsICC was 0.94 [95% CI: 0.90–0.96] in TSD and 0.99 [95% CI: 0.98–0.99] in TAD. The error was −0.35 mm (−1.83 mm to 1.12 mm) in TSD and +0.63 mm (−5.65 mm to 4.59 mm) in TAD. RMSE was 0.63 mm in TSD and 1.53 mm in TAD. Pearson’s correlation coefficient was 0.79 [95% CI: 0.66–0.87] in TSD and 0.83 [95% CI: 0.72–0.89] in TAD. There were no adverse events with ADAPT use.ConclusionADAPT is highly accurate and useful in guiding surgeons in properly positioning the screws.     

基于腹腔镜手术训练的眼动特征研究

在腹腔镜模拟训练过程中,研究不同训练模式下被测试者的注视策略,探索腹腔镜训练的新模式。被测试者被随机分为无指导组,视频学习组和专家指导组进行左右移环任务。利用Tobii X1 Light型眼动仪调用模拟训练箱中的摄像头,采集受试者的眼动数据。通过对数据处理分析,计算注视点个数,平均注视时间,注视时间百分比,扫描距离指标。与对照组相比,视频学习和专家指导模式下,任务完成时间降低23%,扫描距离缩短25%,注视点个数减少17%,平均注视时间没有显著差异。视频组和专家指导组之间无明显差异。结果表明不同学习模式下,被测试者的注视行为有明显差异。视频学习和专家指导下效果更好,可以用专家操作时的注视点视频指导初级训练者进行训练。     

单中心乳腺癌术后乳房重建的影响因素

背景与目的：乳腺癌手术方式的选择受到诸多因素影响，本研究旨在分析乳腺癌患者选择乳房重建手术的影响因素，重点探讨居住地距离与乳房重建的关系。方法：回顾性分析了1999年1月—2015年12月复旦大学附属肿瘤医院收治的因单侧或双侧0～Ⅱ期乳腺癌行全乳切除术的女性患者临床资料，分析居住地距离与乳房重建比例的关系。结果：非上海患者选择全乳切除术后乳房重建比例高于上海患者(6.1% vs 4.5%，P<0.001)。居住地距离影响乳房重建比例(P=0.035)。单因素分析显示，居住地距离越远，选择乳房重建手术比例越高，而年龄、体质量指数(body mass index，BMI)、TNM分期与乳房重建的选择呈负相关(P均<0.001)。多因素分析显示，年龄增长、BMI增加、TNM分期较晚是拒绝行乳房重建的独立影响因素(P均<0.001)，而居住地距离不是乳房重建的独立影响因素(P>0.05)，且与具体乳房重建方式无交互作用。年龄与居住地距离呈负相关(P<0.001)。结论：乳腺癌患者的居住地距离与乳房重建比例呈线性相关；年龄、BMI和疾病分期是影响乳房重建的主要因素。