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Hyperextension of the fetal head in the breech presentation can be diagnosed by ultrasound. Straightening of the fetal spine and the widest diameter of the skull posterior to the long axis of the spine is diagnostic. Face presentation should also be diagnosable by these criteria. 相似文献
23.
低强度超声联合微泡触发的声空化效应作用于组织器官后,会产生一系列生物学改变,为治疗疾病提供了新型、无创、高效的方案,具有广阔应用前景。本文对低强度超声联合微泡在肿瘤化疗及动脉溶栓方面的进展进行综述。 相似文献
24.
An ultrasonic scanning system has been devised, utilizing an array of six plane transducers, each used as a separate transmitter-receiver. The transducers were arranged in a concave assembly so that their beams intersected at a point equidistant from each face. The array was mounted in a water-bath on a three-dimensional racking mechanism, so that it could be moved through a raster at various heights in the tank. In a fixed sequence, each individual transducer was excited, and the received ultrasonic echo amplitude information from the focus was selected by means of an electronic gate. The cartesian coordinates of the position of the array were also determined. Both sets of information were sampled, digitized and punched on to paper tape. A switching sequence was arranged so that eight successive characters on the paper tape represented the six echo amplitude data and the two positional data corresponding to a single point in the tank. The array was moved so that a two-dimensional matrix of points was interrogated.Experiments were performed to test the operating characteristics of the apparatus and to determine appropriate methods of signal processing and for the display of the information. It was found that the alignment of the ultrasonic beams was satisfactory and the data acquisition system was linear over a dynamic range approaching 40 dB. The apparatus was used to scan a simple model of wires and an isolated porcine kidney. Improved aximuthal resolution was achieved by combining the six amplitude data for each point. The product of these data seemed to be more useful than the sum. Contour mapping of received echo amplitude gave a satisfactorily wide dynamic range display.Possible future developments of the system are discussed. 相似文献
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J. Jellins G. Kossoff J. Wiseman T. Reeve I. Hales 《Ultrasound in medicine & biology》1975,1(4):405-410
Ultrasonic examination of the thyroid provides an accurate method of differentiating between solid and cystic lesions. With grey scale echography contents of many solid lesions give rise to a characteristic echo pattern which may eventually allow the ultrasonic classification of these lesions. This preliminary study of 40 patients presents the echograms associated with some of the more common pathological conditions of the thyroid gland. 相似文献
26.
James A. Rothendler Donald L. King William M. Green 《Journal of clinical ultrasound : JCU》1976,4(2):139-140
Circuitry for simultaneous recording from dual transducers on a single echocardiogram is presented. The technique may be used to compare the motion pattern and time intervals of separate intracardiac structures. The technique may be difficult, is limited by the size of the cardiac window, and may be most useful for research purposes. 相似文献
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目的 观察第四代超声碎石清石系统治疗尿路结石的临床疗效.方法 回顾分析243例尿路结石患者应用第四代EMS超声碎石清石系统进行腔内治疗临床资料.结果Ⅰ期成功碎石取石227例,Ⅰ期清石率为93.3%(227/243),Ⅱ期碎石16例.并发症2例,其中术中液气胸1例,留置胸腔闭式引流管处理;术后出血严重经保守治疗效果欠佳介入治疗行超选择性肾动脉介入栓塞治愈1例.结论 第四代超声碎石清石系统能够对泌尿系各不同解剖位置的结石进行治疗,是一种安全实用、高效的碎石系统,值得临床应用. 相似文献
29.
Okubo M Kawasaki M Ishihara Y Takeyama U Kubota T Yamaki T Ojio S Nishigaki K Takemura G Saio M Takami T Minatoguchi S Fujiwara H 《Ultrasound in medicine & biology》2008,34(4):655-663
Tissue characterization of plaques of coronary arteries is important to clarify the process of acute coronary syndrome and prevent it. The purpose of this study is to develop an online integrated backscatter intravascular ultrasound (IB-IVUS) system and validate the diagnostic accuracy for the characterization of coronary plaques. A personal computer equipped with custom software was connected to an IVUS imaging system. Images were acquired from 242 segments of 46 coronary arteries from 25 cadavers obtained at autopsy. In the training study, a total of 724 regions-of-interests on color-coded maps were compared with histologic images. In the validation study, a total of 192 cross-sections of coronary arteries were evaluated. Receiver operating characteristic curve analysis showed that the cut-off points of -49 dB (area under curve = 0.98) and -29 dB (area under curve = 0.99) were the most reliable predictors of lipid pools, fibrosis and calcification. In the validation study, the analysis using IB values classified fibrous, lipid-rich and fibrocalcific plaque components with a high accuracy of 93%, 90% and 96%, respectively. The overall agreement between histologic and IB-IVUS diagnoses (n = 175) was high (Cohen's kappa = 0.81). The IB-IVUS system provides high diagnostic accuracy for analysis of tissue characteristics of coronary plaques. 相似文献
30.