Clinical equivalence assessment of T2 synthesized pediatric brain magnetic resonance imaging

Background and purposeAutomated synthetic magnetic resonance imaging (MRI) provides qualitative, weighted image contrasts as well as quantitative information from one scan and is well-suited for various applications such as analysis of white matter disorders. However, the synthesized contrasts have been poorly evaluated in pediatric applications. The purpose of this study was to compare the image quality of synthetic T2 to conventional turbo spin-echo (TSE) T2 in pediatric brain MRI.Materials and methodsThis was a mono-center prospective study. Synthetic and conventional MRI acquisitions at 1.5 Tesla were performed for each patient during the same session using a prototype accelerated T2 mapping sequence package (TA_synthetic = 3:07 min, TA_conventional = 2:33 min). Image sets were blindly and randomly analyzed by pediatric neuroradiologists. Global image quality, morphologic legibility of standard structures and artifacts were assessed using a 4-point Likert scale. Inter-observer kappa agreements were calculated. The capability of the synthesized contrasts and conventional TSE T2 to discern normal and pathologic cases was evaluated.ResultsSixty patients were included. The overall diagnostic quality of the synthesized contrasts was non-inferior to conventional imaging scale (P = 0.06). There was no significant difference in the legibility of normal and pathological anatomic structures of synthetized and conventional TSE T2 (all P > 0.05) as well as for artifacts except for phase encoding (P = 0.008). Inter-observer agreement was good to almost perfect (kappa between 0.66 and 1).ConclusionsT2 synthesized contrasts, which also provides quantitative T2 information that could be useful, could be suggested as an equivalent technique in pediatric neuro-imaging, compared to conventional TSE T2.     

基于仿真胸腔生物力学特性的新型模拟人在心肺复苏教学训练中的应用

目的　采用多弹簧组变阻尼结构模拟真实的人体胸腔生物力学特性,结合原有的电子反馈系统设计出一款基于仿真胸腔生物力学特性的新型心肺复苏训练模拟人,并测试其在心肺复苏（cardiopulmonary resuscitation,CPR）教学中的应用效果。方法　选取海军军医大学2019级五年制临床医学专业的60名本科学员作为研究对象,分成试验组和对照组,每组30名。对照组使用传统模拟人进行CPR培训,试验组在对照组基础上应用新型模拟人进行CPR培训。培训结束后对两组人员分别进行单项技能考核。单项技能主要是徒手进行心肺复苏操作,包括人工呼吸与胸外按压。比较两组的CPR理论和技能操作考核情况及对教学方法的满意度。采用SPSS 23.0进行统计学分析。结果　试验组学员单项技能操作考核成绩为（54.33±3.09）分,优于对照组学员（52.33±3.08）分,差异有统计学意义（P <0.05）。调查问卷显示,试验组学员对于新型模拟人的教学训练效果评价较好。结论　新型心肺复苏模拟人相比传统模拟人,更能够模拟真实人体的心肺复苏急救场景,可以有效提高医学学员规范化培训CPR教学效果,助力我国心肺急救技术的标准化、规范化、普及化工作。     

模拟教学联合心理暗示在耳鼻咽喉头颈外科住培模拟教学中的应用

目的 分析模拟教学联合心理暗示在耳鼻咽喉头颈外科住培模拟教学中的应用价值。方法 选取于清华大学附属北京清华长庚医院耳鼻咽喉头颈外科进行住培的36例住培医师,按不同教学模式将其分为研究组（n=20,模拟教学联合心理暗示）与对照组（n=16,传统教学）。比较两组住培医师考核成绩、综合能力、教学效果及教学满意度。采用SPSS 22.0进行t检验和卡方检验。结果 带教后,两组住培医师理论考试、技能考核成绩、学习兴趣、自学能力、沟通能力及临床诊疗水平评分均较带教前上升,且研究组上升程度明显优于对照组（P<0.05）。研究组兴趣程度、难易程度、可参与性、掌握程度评分均明显高于对照组（P<0.05）。研究组住培医师教学总满意度为95.00%,明显高于对照组的68.75%（P<0.05）。结论 模拟教学联合心理暗示在耳鼻咽喉头颈外科住培教学中可提高学员理论知识、技能操作水平、综合能力及教学水平,且学员对该教学方法满意度高。     

C/C复合材料表面等离子喷涂HA涂层在SBF中的试验

目的 探讨不同模拟体液对HA涂层体外生物学行为的影响。方法采用等离子体喷涂法,在碳／碳复合材料表面制备HA涂层,并对涂层进行了热处理。利用X射线衍射仪(X-ray diffraction)、扫描电子显微镜(Scanning electron microscopy)等检测手段,分析该涂层的物相和形貌,观察HA涂层在模拟体液中的影响。结果XRD检测结果表明,在模拟体液浸泡过程中,涂层的主要组成相的相对含量和结晶度不断发生变化。由SEM分析结果可知,在浸泡过程中,内送粉方式下制得的HA涂层的表面沉积物呈现近似网状的结构。同时,在Ringer溶液中,可以观察到HA涂层溶解痕迹。结论通过适当的热处理可以恢复HA的结构完整性,同时提高涂层的结晶度。     

尾部悬吊大鼠胸主动脉、肺动脉超微结构变化的动态观察

目的观察模拟微重力时大小循环动脉血管超微结构重塑随时间变化的差异,为微重力后立位耐力降低的机制研究积累资料。方法用透射电镜观察-30°尾部悬吊7d(TS7组)、14d(TS14组)及对照组大鼠胸主动脉、肺动脉壁超微结构的变化。结果TS7组胸主动脉内皮细胞表面出现绒毛状突起,部分线粒体空泡变性,内皮下基膜有分层,内弹力板较厚,且厚度不均匀,内弹力板下出现大量的胶原纤维;TS14组胸主动脉内皮细胞变性较明显,部分内皮细胞基质致密化,基膜复层化,内弹力板有破碎,弹力纤维增多。TS7组肺动脉部分内皮细胞突起,细胞内出现脂滴,内皮细胞基膜出现分层状改变,弹力板变薄、断裂,其下方可见收缩型平滑肌及合成型平滑肌细胞;TS14组肺动脉内皮细胞空泡变性较明显,内弹力板未见明显改变,弹力板内外均可见较多的胶原纤维和弹力纤维,内弹力板下方以收缩型平滑肌为主。结论TS7组大鼠胸主动脉和肺动脉出现损伤和增殖并存,以肺动脉较明显;TS14组肺动脉趋于形成新的稳定结构,而胸主动脉新稳定结构还未形成。模拟微重力时大小循环血管发生了结构重塑,大小循环血管重塑的时间过程不同归因于模拟微重力初期由下体转移而来的体液进入大小循环高峰期的时间差。     

模拟退火算法在图像配准中的应用

近年来 ,脑功能成像技术发展迅速 ,已在脑科学研究中占有重要地位。研究中通常需要将同一被试的多种模式成像结果或同一模式的时间序列结果结合起来分析 ,首先要解决的问题就是几幅图像的严格对齐问题 ,即所谓的图像配准。在模拟退火算法和其它工作的基础之上 ,较好的解决了图像配准中的连续变量全局优化问题 ,通过基于点的配准方法 ,实现了时间序列脑功能图像的高精度配准。     

Thyroidal handling of radioiodine in sea level residents exposed to hypobaric hypoxia

In the present investigation thyroidal accumulation of radioiodine and its release were assessed by direct testing of thyroid function using radioactive iodine, in vivo, in sea level residents intermittently exposed to hypobaric hypoxia. Thyroidal accumulation of radioiodine and its turnover were examined daily for 14 days. Twelve healthy human male volunteers were divided into three groups, with an equal number of individuals in each group. A decompression chamber was used to expose each group of subjects to hypoxic conditions at a simulated altitude of 3810 m for 8 h/day for 14 days. An oral dose of 25Ci iodine-131 was administered to each individual of the first group immediately before the initiation of intermittent hypoxia. The second group of subjects received a tracer dose at the beginning of the 4th day of the 14 days, intermittent exposure to hypoxia, while the third group received the tracer dose 1 week after the completion of the exposure. Control studies were carried out on the subjects before they were subjected to the experimental conditions. Thyroidal accumulation of¹³¹I in experimental subjects during the hypoxic state and in the post-hypoxic state was higher than in the control studies. The pattern of accumulation during exposure to hypoxia and in the post-hypoxic state showed multiple peaks of radioactive iodine uptake (PRAIU), a unique feature. The multiple PRAIU by the thyroid in experimental subjects were sharp and of short duration, reflecting an increased rate of¹³I release from the thyroid. Control subjects had a single PRAIU by the thyroid 24 h after the administration of tracer.     

基因表达数据判别分析的随机森林方法

目的探讨随机森林算法在基因表达数据分类研究中的应用。方法通过实际基因表达数据考核其应用效果，并通过模拟试验进一步验证和研究在存在大量无差异表达基因情况下对分类产生的影响。结果随机森林算法对基因表达数据的分类具有较高的准确性，但随着基因数量的增加其判别效果呈下降的趋势，在差异表达基因之间具有相关性时，下降趋势明显减慢，能够获得较理想的分类效果。结论随机森林算法对基因表达数据的分类研究有较好的判别效果。     

Aiding risk information learning through simulated experience (ARISE): Using simulated outcomes to improve understanding of conditional probabilities in prenatal Down syndrome screening

ObjectiveTo determine whether the use of visually-presented simulated experiences to communicate statistical information can improve an individual’s understanding of conditional probabilities—specifically the positive predictive value (PPV) of prenatal screening tests for Down syndrome.MethodsIn Experiment 1 (N = 64) and Experiment 2 (N = 180) participants were asked to estimate the PPV of a prenatal screening test for Down syndrome based on either (1) explicit statistics regarding the prevalence of Down syndrome and the sensitivity and specificity of a prenatal screening test for Down syndrome, or (2) experiencing up to 5000 simulated test results over a short time.ResultsParticipants’ estimates of the PPV were more accurate when they had learned via simulated experiences (79% accuracy) compared with estimates based on explicitly described statistics (14%). Participants in the simulated experience condition also reported decreased interest in screening and decreased concern with a positive test result.ConclusionA visual paradigm presenting simulated experiences improves PPV estimates, compared to estimates derived from explicitly provided statistics, while also shifting attitudes away from screening.Practice implicationsThe use of simulated experiences may prove to be simple but powerful tool to communicate complex statistical information to patients in medical decision making situations.     

Amelioration of Endotoxin-Induced Uveitis in Rabbit by Topical Administration of Tacrolimus Proglycosome Nano-Vesicles

This work was aimed to improve the efficacy of tacrolimus in the treatment of endotoxin-induced uveitis (EIU) using propylene glycol modified lipid vesicles termed as proglycosome nano-vesicles (PNVs). PNVs were prepared by modified film hydration method. Experimental uveitis in rabbit eye was induced by an intravitreal injection of 20 μL of the endotoxin solution containing 100 ng of lipopolysaccharide endotoxin. In vivo efficacy of PNVs was determined by studying clinical symptoms of uveitis using slit lamp examination and by quantitatively measuring levels of tumor necrosis factor-alpha, interleukin-6, leukocytes and total proteins in aqueous humor, 24 h after intravitreal injection of endotoxin. Comparison was made with healthy, untreated and tacrolimus solution treated eyes. PNVs developed were nano-sized, deformable and showed sustained release of tacrolimus over period of 12 h. In vivo results indicated statistically significant difference between the effects of PNVs in the treatment of EIU compared to tacrolimus. PNV treatment not only subsides clinical symptoms of uveitis but also prevented breakdown of blood aqueous barrier. Tacrolimus loaded PNVs are potential new topical treatment for uveitis.