阴囊闭合性损伤的CT与MRI诊断价值

目的探讨CT与MRI对阴囊闭合性损伤的诊断价值。方法回顾性分析12例临床证实的阴囊损伤的CT和（或）MRI资料。12例患者,4例同时有CT与MRI资料,5例、3例分别进行CT、MRI检查。结果阴囊壁肿胀11例,鞘膜积液9例,白膜下血肿2例,睾丸挫伤伴血肿6例,附睾挫伤2例,睾丸白膜破裂1例。结论 CT简单快速、较为准确,尤其适于急性期检查,MRI显示阴囊损伤更为精确,更适用于该病的重复检查和疗效观察。     

下胫腓联合损伤采用X线、多层螺旋CT及MRI联合Weber分型的诊断价值

目的:观察下胫腓联合损伤采用X线、多层螺旋CT及MRI联合Weber分型的诊断价值。方法:将2019年1月至2021年1月我院收治的71例下胫腓联合损伤患者为研究对象。对比X线、多层螺旋CT及MRI联合Weber分型诊断下胫腓联合损伤患者准确率、阳性预测值、阴性预测值、灵敏度及特异度。结果:71例下胫腓联合损伤患者经MRI诊断结果为:31例A型占43.66%(31/71)、23例B型占32.39%(23/71)、17例C型占23.94%(17/71)。以MRI诊断结果为金标准,X线、多层螺旋CT及MRI联合Weber分型诊断下胫腓联合损伤患者准确率A型占100.00%(31/31)、B型占95.65%(22/23)、17例C型占100.00%(17/17)高于多层螺旋CT诊断下胫腓联合损伤患者准确率A型占93.55%(29/31)、B型占91.30%(21/23)、C型占88.24%(15/17)(P<0.05);多层螺旋CT、多层螺旋CT及MRI联合Weber分型诊断均高于X线诊断下胫腓联合损伤患者准确率A型占83.97%(26/31)、B型占82.61%(19/23)、C型占...     

SARS冠状病毒基因组及相关研究报告

引发在全世界范围内广泛流行的重症急性呼吸道综合症的病原微生物是一种未被科学家完全认识的新的冠状病毒。本文报告了SARS冠状病毒(B101)基因组概貌、开放阅读框架、变异特征、遗传进化、临床免疫检测方法及作为烈性传染病对SARS相关生物检材研究所必需的实验室条件——生物安全三级实验的基本要求。     

Material influence in coordinate measurement using X-ray CT

The X-ray computed tomography system (XCT) as a coordinate measuring system has been increasingly introduced into the manufacturing industry because of its capability of measuring internal features. However, the metrological performance evaluation method for XCT has not yet been standardized. One of the biggest reasons of this is the difficulty in evaluating the material influence. The previous research by the authors revealed that the material influence significantly affects the form of the object to be measured. ISO/TC 213/WG 10, which covers the ISO standards of coordinate measuring machines, proposes the introduction of an additional object, called an “obstructive body,” by which the material influence is enhanced. This study presents the experimental results and a software simulation, in which the material influence is produced in a specific area and not on the entire surface of the test object. Additionally, requirements for the obstructive body in the industrial standardization of performance evaluation methods for XCT are proposed.     

X-ray visualization measurement of slurry flow in solid propellant casting

Simulated solid propellant slurry containing lead sphere tracers is experimentally cast into a double-circular cylindrical container. During the casting, the temperature and the pressure environment has been mimicked to an actual composite solid propellant casting of solid rocket motors. X-rays are projected on to the slurry flow from two directions and penetration images are recorded by a flat-panel detector and an X-ray image intensifier. By suppressing the mutual interference of the X-rays, the two-directional X-ray photography has been successfully conducted. Using the time series data of the X-ray images from the two directions, the identification of each tracer particle in space and time has been done and their three-dimensional paths have been computed. From these procedures, the flow field or the velocity field inside the slurry flow, which is usually invisible, has been estimated.     

X光工业用CT成像二代扫描运动控制系统设计

分析X光工业用CT成像二代扫描的特点,提出了实现二代扫描的两种运动控制方案.分析并比较了二代扫描的平移和分度运动(平移+旋转)之间的关系,提出了提高系统扫描效率的两种方案.在此基础上,确定了由上位机和下位机组成的分布式运动控制系统的总体方案,设计了相应的硬件电路及软件,获得了预期的试验效果.     

应用电子束CT低剂量扫描在冠状动脉CT成像病人中筛查早期肺癌

目的:探讨新一代电子束CT(e-SPEED)在行冠状动脉CT成像检查病人中联合筛查早期肺癌的扫描方法及应用价值。方法:对104例健康查体者先行肺部低剂量电子束CT扫描,扫描参数为130kV,895mA,50ms,层厚6mm,层距3mm,重建层厚3mm。平扫后再经静脉注射对比剂进行CT冠状动脉成像检查,其中48例(心率≥70次/分)行电子束CT扫描,扫描参数为Multiphase Dual方式,140kV,1010mA,100ms,层厚1.5mm;57例(心率<70次/分行16排螺旋CT扫描,扫描参数为120kV,370mA,500ms,层厚0.625mm。对比剂选用非离子型Ommipaque 350mgI/mL。肺平扫图像采用肺算法及标准算法重建,由两位放射诊断医师在工作站显示器上进行观察,统计病变检出例数并观察肺叶、段支气管显示情况;并对冠状动脉CT增强图像以VR、MIP、CINE、CTVE方式重建后进行观察,利用其薄层扫描的优势重点观察肺门结构及支气管开口情况,并观察可疑病变的强化情况。所有图像存贮至图像存储与传输系统(PACS)。结果:100%肺叶、段支气管可显示,共检出3mm以上非钙化肺结节4例,其中1例经活检证实为I期周围型肺癌。结论:在冠状动脉CT成像检查同时配合电子束CT低剂量平扫,适于联合筛查早期肺癌,并有助于提高肺内非钙化小结节及支气管细微病变的检出。     

Effects of off-focal radiation on dimensional measurements in industrial cone-beam micro-focus X-ray computed tomography systems

A study of the secondary source phenomenon due to the presence of off-focal radiation in industrial micro-focus cone-beam X-ray computed tomography (XCT) systems and its influence on dimensional measurements is presented. Although off-focal radiation production within X-ray tubes has been studied for medical X-ray imaging systems, its properties and its effects on dimensional measurements in industrial XCT systems have not been discussed prior to this research. The study comprises: evaluation of the geometrical properties of off-focal radiation through a theoretical and experimental study of two-dimensional projection images of the scanned objects, verification of these properties using computer simulations and evaluation of the impact of the secondary source on dimensional measurements using experimental and simulation approaches. In addition, ways to minimise the effects of off-focal radiation are discussed, and reference samples for characterising the properties of off-focal radiation are proposed.     

Sensitivity of X-ray computed tomography measurements of a gas-solid flow to variations in acquisition parameters

Due to its high spatial resolution and non-invasive nature, X-ray computed tomography has become a popular method for determining the flow characteristics of multiphase flows. However, because many of the X-ray computed tomography systems used for non-destructive imaging of multiphase flows provide the operator wide leeway in the selection of imaging parameters, the potential exists for errors to be introduced into the measurements if the algorithms are sensitive to these changes. In this paper, a representative multiphase flow (specifically, a fluidized bed) is imaged with a wide range of X-ray tube electrical potentials, currents, and detector exposure times and reconstructed with a wide range of centers of rotation. The results of these tests show that while the raw CT intensities are sensitive to these parameter variations, once the measurements are calibrated to reference images (in this case through a void fraction calculation), the final results are insensitive to most changes. In the extreme cases where there is some sensitivity to the parameter changes, the causes and practical implications are discussed.     

Relationship between the anisotropy tensor calculated through global and object measurements in high-resolution X-ray tomography on cellular and composite materials

Structural anisotropy of two-phase materials can be evaluated through global measurements, as volume orientation or mean-intercept length methods do, or through statistics performed on a set of individual measurements. This last procedure is encouraged by recent improvements in the spatial resolution of conventional X-ray tomography. In this paper, the above-described approaches were compared in three case studies: a foam subjected to an in situ compression test, a second foam with a completely different cell morphology and a plastic material reinforced with short fibres. The approach based on the subdivision into distinguishable objects of the considered material phase has proved to be more sensitive in highlighting small deformations in the structure or small irregularities in an otherwise isotropic structure. On the other hand, the other approach is more general and is always usable. The two methods for calculating the fabric tensor tend to converge as the average anisotropy of individual objects in the statistical population increases. The use of Lambert's cylindrical equal-area projection of cell/fibre directions or local volume orientations is suggested, because the density of points is preserved from the sphere to the plane surface. Finally, a quick vector method to evaluate the anisotropy of the directions distribution has been presented, by defining a coherence index of the average direction.     

High-resolution X-ray tomography of the human inner ear: synchrotron radiation-based study of nerve fibre bundles, membranes and ganglion cells

The combination of osmium tetroxide staining and high-resolution tomographic imaging using monochromatic X rays allows visualizing cellular structures of the human inner ear, that is, the organ of Corti, the stria vascularis and further soft tissues of the membranous labyrinth, in three-dimensional space with isotropic micrometre resolution. This approach permits to follow the course of nerve fibre bundles in a major part of the specimen and reveals the detailed three-dimensional arrangement of individual ganglion cells with distinct nuclei by means of X-ray tomography for the first time. The non-destructive neuron cell counting in a selected volume of 125 μm × 800 μm × 600 μm = 0.06 mm³ gives rise to the estimate that 2000 ganglion cells are present along 1 mm organ of Corti.