Comparison study of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography

Objectives: To directly compare the quality of harmonic imaging (HI) and fundamental imaging (FI) in fetal echocardiography and to determine any differences in image quality between the two modalities. Methods: Fetal echocardiograms were performed with the use of FI and HI in 58 fetuses, image quality and visualization of left and right atria, left and right ventricles, mitral and tricuspid valves, aortic and pulmonary valves, left and right ventricular outflow tracts were evaluated and compared between FI and HI. Results: Mean HI scores were higher than mean FI scores (2.73±0.43 vs 2.16±0.69, P<0.001)for all the cardiovascular structures evaluated. Compared with FI, HI improved the image quality and visualization of fetal cardiac structures in subjects with both good (2.73±0.43 vs 2.88±0.32, P<0.001) and suboptimal (1.65±0.41 vs 2.58±0.47, P<0.001) echocardiographic windows. The interobserver correlation coefficient for the grading scores was 0.74 (P<0.001). Conclusions: harmonic imaging enhances and improves the image quality of fetal echocardiography; and has important potential role in cardiac imaging in the fetus.     

成像系统对图像的退化作用

文中讨论了成像系统对静止图像质量产生的影响,综合考虑系统的各个组成部件的传递函 数,建立成像系统对图像退化的模型(传递函数),通过计算机模拟生成了退化后的图像。     

基于GIS和高分辨SAR数据的机场净空建筑物高度提取

随着SAR图像分辨率的进一步提高,建筑物在SAR图像中的特征更加明显,使得基于单幅高分辨率SAR图像进行建筑物提取和三维重构成为可能。分析高分辨率SAR图像中建筑物的成像散射特征,多次反射及阴影效应;阐述基于GIS空间数据进行SAR图像中建筑物定位和估算建筑物的高度的算法。利用高分辨率TerraSAR-X数据,估算天津机场净空区某小区建筑物高度,与实际高度数据相比较,发现计算结果精度较高。结果表明:该方法是一种可行的建筑物高度提取方法,可为需要大面积建筑物高度的相关应用提供很好的借鉴方法。     

Study of clinical features of amyloid angiopathy hemorrhage and hypertensive intracerebral hemorrhage

Objective: The purpose of this study was to differentiate between cerebral amyloid angiopathy (CAA) and hypertension (HTN) based on hemorrhage pattern interpretation. Methods: From June 1994 to Oct., 2000, 83 patients admitted to our service with acute intracerebral hemorrhage (ICH) were investigated retrospectively; 41 patients with his-tologically proven diagnosis of cerebral amyloid angiography and 42 patients with clear history of hypertension were investigated. Results: Patients with a CAA-related ICH were significantly older than patients with a HTN-related ICH (74.0 years vs 66.5 years, P<0.05). There was a significantly higher number of hematomas>30 ml in CAA (85.3%) when compared with HTN (59.5%). No basal ganglional hemorrhage was seen in CAA, but in 40.5% in HTN. In CAA-related ICH, su-barachnoid hemorrhage (SAH) was seen in 26 patients (63.4%) compared to only 11 patients (26.2%) in HTN-related ICH. Intraventricular hemorrhage was seen in 24.4% in CAA, and in 26.2% in HTN. Typical features o     

影像启发式教学与思维导图在医学新生研讨课程实践中的联合应用

以新生研讨课“土壤污染与人类健康”为例,将视频观看模式关联的启发式教学与思维导图模式的思考方式相结合融入教学过程,以探讨新的教学模式。从课程背景、教学过程、教学反思三个层面阐述,实践表明该教学模式可提高学生自主学习能力,轻松掌握知识以及养成良好的思维习惯。最后文章还提出了该教学模式应注意的几个问题。     

High-Resolution Ultrasonic Imaging of Artworks with Seismic Interferometry for Their Conservation and Restoration

Artworks are an inseparable part of the cultural heritage of societies and provide us with a unique look at cultural developments through time and space. For the best possible conservation, it is paramount to know the constituent materials, condition, and construction techniques of the objects (e.g. painting on wood, fresco, sculpture). Such information is required not only for the surfaces of the objects, but also for the interiors; in the imaging discipline, this is known as depth imaging. Here, we introduce a new method for non-invasive depth imaging as an alternative to traditional non-invasive methods when the latter cannot be used to obtain the required information. We use ultrasonic transverse-wave transmission measurements and turn them into virtual reflection measurements. We achieve this by applying seismic interferometry with active sources. Obtaining reflection measurements by seismic interferometry allows us to apply an advanced imaging technique – prestack depth migration, as used in seismic exploration – to produce a high-resolution depth image of an object. We apply our method to ultrasonic data recorded on a mockup of a painting on a wooden support. We validate our method by comparing our results with an image from X-ray computed tomography.     

青少年急性膝关节创伤性骨髓异常与创伤机制及软组织损伤的关系

目的：初步探讨青少年急性膝关节创伤性骨髓异常与创伤机制及软组织损伤的关系。方法：回顾性分析69例青少年急性膝关节损伤患者的临床及影像学资料。通过膝关节磁共振成像（MRI）评估创伤性骨髓异常的部位及前交叉韧带、后交叉韧带、内侧副韧带、外侧副韧带及内、外侧支持带等软组织的损伤,根据临床资料汇总创伤机制。结果：69例患者包括19例轴移损伤,17例髌骨外侧脱位,12例过伸伤,11例外翻损伤和10例仪表盘损伤。轴移损伤引起创伤性骨髓异常部位多位于股骨外侧髁后区（94.7%）、股骨外侧髁前区（84.2%）和胫骨外侧平台后区（78.9%）,常伴有前交叉韧带撕裂（94.7%）。髌骨外侧脱位多位于髌骨（100%）、股骨外侧髁后区（100%）和股骨外侧髁前区（94.1%）,常伴有内侧支持带撕裂（88.2%）。过伸伤主要累及胫骨内侧平台前区（83.3%）、胫骨外侧平台前区（75%）和股骨内侧髁前区（66.7%）,常伴有前交叉韧带（91.7%）和后交叉韧带损伤（58.3%）。外翻损伤主要累及股骨,包括股骨外侧髁后区（72.7%）,股骨外侧髁前区（54.5%）和股骨内侧髁前区（45.5%）,常伴有内侧副韧带损伤（90.9%）。仪表盘损伤主要累及胫骨,包括胫骨外侧平台前区（100%）、胫骨内侧平台前区（90%）,常伴有后交叉韧带损伤（70%）。结论：青少年急性膝关节创伤性骨髓异常在MRI上的分布代表了特定的创伤机制的足迹,并能够精准地预测特定的软组织损伤。     

基于小世界网络分析的小球类专项学生运动员脑网络可塑性变化研究

目的:基于小世界分析方法,探测小球类专项学生运动员大脑的结构网络及功能网络的可塑性变化。方法:收集小球类专项学生运动员和与之匹配的普通被试作为对照组,采集静息态,3DT1及DTI磁共振数据。首先根据DTI纤维追踪结果构建结构网络,根据功能连接构建功能网络。进一步计算不同稀疏度下的结构及功能网络的网络属性。结果:通过计算其网络属性发现,小球类专项学生运动员与普通被试的结构及功能网络都具有小世界特性。小球类专项学生运动员组的结构网络及功能网络的聚类系数和局部效率比对照组高,在部分稀疏度下存在明显差异。其中,结构和功能网络的全局聚类系数显著相关。结论:小球类专项学生运动员大脑的结构网络及功能网络的聚类系数和局部效率比普通被试高,且结构和功能网络的全局聚类系数显著协变,说明小球类专项学生运动员的脑连接比普通被试多,脑区之间通信更加迅速有效,信息容错能力更强,且小球类专项学生运动员的脑结构、功能网络具有一致的可塑性变化。     

Making Cognitive Neuroscience Educationally Relevant: Creating Bidirectional Collaborations Between Educational Psychology and Cognitive Neuroscience

Not only should educational psychologists keep abreast of developments in the rapidly evolving field of brain science, but also they should contribute their knowledge of higher cognitive functioning and instructional interventions to this field. Linking imaging studies with instructional studies may shed light on causal mechanisms in brain function. The importance and challenges of studying the brain at different levels of analysis are discussed and illustrated with examples from the reading literature and the deafness literature.     

高分辨率SAR子孔径图像相干性分析及其地物分类应用

针对相干性这一合成孔径雷达(SAR)图像分析常用的特征量进行分析,首先从理论上分析高分辨率SAR图像中人造目标和自然地物等典型目标的子孔径、子频带以及不同子孔径重轨干涉图像间的相干系数,然后利用高分辨率星载SAR实际数据开展上述相干系数的计算,验证分析的正确性。随后根据不同地物在不同维度相干系数上体现的不同特点,进行非监督地物分类,并给出不同类别所表征的地物特点。分析结果可为高分辨率SAR数据的优化应用提供支撑,并可加深对SAR不同地物目标特性的理解。