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1.
Waseem Raza Hafiza Anum Mohy-u-Din Sajid Shaeen Malik Iqra Manzoor Baby Nadeem 《Ultrasound in medicine & biology》2019,45(1):21-25
The objective of the study was to evaluate the reliability of sonoelastography in ductal carcinoma in patients in primary and secondary health care settings. Google Scholar, PubMed, Medline, Medscape, Wikipedia and NCBI were searched in January 2018 for all original research and review articles to identify relevant studies. Two reviewers selected the articles independently for based on the title and abstract. The selection criteria were sonoelastography accuracy for diagnosing ductal carcinoma as index text, B-mode sonography, and micropure imaging; surgery and histologic findings were used as reference text; and benign and malignant breast abnormalities and ductal carcinoma were used as target conditions. Two reviewers extracted the data on selected study characteristics, and the results were used to construct the tables and figures. Fifteen studies on ductal carcinoma were found. The overall sensitivity of sonoelastography in diagnosing ductal carcinoma was 85.7%, and the specificity, 79.8%. On the basis of the literature review, it was concluded that sonoelastography has high sensitivity and specificity in diagnosing ductal carcinoma. 相似文献
2.
目的 :研究SRS2 0 0X 刀治疗系统治疗靶点定位的精确度。方法 :应用人体头颅模型内特定标记物测定CT定位的精度 ,用胶片法测定二次等中心系统精度和总的治疗精度。结果 :BRW头环CT定位精度为 0 .65mm ,最大误差为 1 .0 9mm ;SRS2 0 0二次等中心系统误差为 0 .1 9mm ;总治疗误差理论计算值为0 .68mm ,胶片法检测值为 1 .43mm。结论 :X 刀治疗系统精确度已达到放射外科质量控制要求。 相似文献
3.
目的目前国内对QCT骨密度测量的质量控制研究较少,本文介绍了QCT骨密度测量的准确度、精密度试验方法和意义。方法使用东芝CT机自带体模和软件为测量工具,测量四川大学华西骨质疏松研究中心等研制的QCT骨体模(称四川体模)的骨密度值。四川体模固定于15cm深的水浴中模拟人体腰椎,东芝体模置于水浴容器与扫描床面之间,按照人腰椎QCT骨密度测量相同的条件和方法进行操作,每日1次对测量体模连续测量25日,计算SD和CV,分别以25次测量125d25次测量/1d基线作3m的shewhart图。结果测量四川体模从小到大三管骨密度分别的准确度误差为-60.4%、-39.1%和-13.6%,其分别的校正系数为2.69、1.64、1.15,相关系数为0.9966,回归方程Y=35.6+0.958X(X为测量骨密度,Y为校正后骨密度)。本型QCT机骨密度测量的25次/1d及25次,25d精密度误差分别为1.25~5.54%和1.98~7.87%。25次125d的精密度误差要大于25次,d,显示机器一日内精密度误差变化小,随时间延长其变化增大。以25次125d的结果为基线绘制的shewhart图优于25次/d。结论一切QCT骨密度测量都应进行质量控制,准确度必须予以校正,精密度试验应在此基础上进行。这样结果才真实、科学、可靠并具有可比性。 相似文献
4.
James Gordon Maria Felice Ghilardi Scott E. Cooper Claude Ghez 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1994,99(1):97-111
This study examined the variability in movement end points in a task in which human subjects reached to targets in different locations on a horizontal surface. The primary purpose was to determine whether patterns in the variable errors would reveal the nature and origin of the coordinate system in which the movements were planned. Six subjects moved a hand-held cursor on a digitizing tablet. Target and cursor positions were displayed on a computer screen, and vision of the hand and arm was blocked. The screen cursor was blanked during movement to prevent visual corrections. The paths of the movements were straight and thus directions were largely specified at the onset of movement. The velocity profiles were bell-shaped, and peak velocities and accelerations were scaled to target distance, implying that movement extent was also programmed in advance of the movement. The spatial distributions of movement end points were elliptical in shape. The major axes of these ellipses were systematically oriented in the direction of hand movement with respect to its initial position. This was true for both fast and slow movements, as well as for pointing movements involving rotations of the wrist joint. Using principal components analysis to compute the axes of these ellipses, we found that the eccentricity of the elliptical dispersions was uniformly greater for small than for large movements: variability along the axis of movement, representing extent variability, increased markedly but nonlinearly with distance. Variability perpendicular to the direction of movement, which results from directional errors, was generally smaller than extent variability, but it increased in proportion to the extent of the movement. Therefore, directional variability, in angular terms, was constant and independent of distance. Because the patterns of variability were similar for both slow and fast movements, as well as for movements involving different joints, we conclude that they result largely from errors in the planning process. We also argue that they cannot be simply explained as consequences of the inertial properties of the limb. Rather they provide evidence for an organizing mechanism that moves the limb along a straight path. We further conclude that reaching movements are planned in a hand-centered coordinate system, with direction and extent of hand movement as the planned parameters. Since the factors which influence directional variability are independent of those that influence extent errors, we propose that these two variables can be separately specified by the brain. 相似文献
5.
L Kovacs A Zimmermann G Brockmann M Gühring H Baurecht N A Papadopulos K Schwenzer-Zimmerer R Sader E Biemer H F Zeilhofer 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(11):1193-1202
Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces. 相似文献
6.
行列资料诊断试验预告值和准确度的一次性标化研究 总被引:1,自引:0,他引:1
本文建立了行列资料诊断试验预告值和准确度的一次性标化方法,省去了标化过程理论样本Nt的设定和求有关理论值的计算过程,导出行列资料中标准化Ⅰ级阳性预告值和标准化Ⅱ级阳性预告值、标准化Ⅰ级阴性预告值和标准化Ⅱ级阴性预告值、标准化可疑预告值和标准化准确度的一次性标化公式。分析了标化与非标化预告值的关系及转化规律。 相似文献
7.
目的 探究正电子发射计算机断层显像(PET-CT)对肺癌纵隔淋巴结转移的诊断效能,分析影响诊断效能的相关因素以及肺癌淋巴结转移的影响因素,为临床提供理论参考。方法 选取我院2019年1月—2020年12月收治的经手术病理证实的181例肺癌(476枚淋巴结)患者临床资料进行分析,均行PET-CT进行诊断,分析诊断的效能(灵敏度、特异性、准确性以及阳性/阴性预测值);分析影响PET-CT诊断效能的因素,以及肺癌患者发生纵隔淋巴结转移的相关危险因素。结果 PET-CT诊断肺癌淋巴结转移的灵敏度65.75%(96/146),特异性89.39%(295/330),准确率82.14%(391/476),阳性预测值73.28%(96/131),阴性预测值85.51%(295/345),同手术病理结果相比,差异无统计学意义(P > 0.05)。真阳性淋巴结与假阳性淋巴结的短径、SUVmax值相比较,差异均无统计学意义(P > 0.05);真阳性淋巴结与假阳性淋巴结的密度相比,差异有统计学意义(P < 0.05)。经Logistic回模型分析分析显示,肿瘤的病理类型为腺癌、中央型肺癌、低分化程度是肺癌患者发生纵隔淋巴结转移的危险因素(P < 0.05)。结论 PET-CT诊断肺癌纵隔淋巴结转移有较高的灵敏度、特异性、准确性;诊断的灵敏度受淋巴结的短径与SUVmax值影响,诊断的特异性受淋巴结的密度影响。纵隔淋巴结转移主要与病理类型、病灶部位、分化程度有关。 相似文献
8.
Summary A renewal of ribosomes has been previously reported to occur during gametogenesis in C. reinhardtii. In order to further characterize these new ribosomes, we performed pulse-labelling experiments on whole cells of C. reinhardtii, during gametogenesis and in the presence of various aminoglycosides known to alter translational accuracy: Hygromycin and Paromomycin are assumed to increase the rate of translational errors at the level of 80S and 70S ribosomes whereas Kasugamycin is assumed to induce the opposite effect. Three lines of evidence support an increased inaccuracy in protein translation during gametogenesis: (1) gamete cells displayed a higher sensitivity than vegetative cells to Hygromycin and Paromomycin; 4 g/ml Hygromycin cancelled cytoplasmic protein synthesis in gametes but not in vegetative cells; Paromomycin induced the synthesis of new polypeptides of high molecular weight and of nuclear origin in gametes but not in vegetative cells. In addition, chloroplast protein synthesis was more sensitive to Hygromycin and Paromomycin in gametes than in vegetative cells. (2) Kasugamycin-sensitive alterations of thylakoid membranes were detected during gametogenesis. (3) 35S-misincorporation in the OEE3 polypeptide, of nuclear origin and normally devoid of sulphur containing amino acids, was more than three times higher in gametes than in vegetative cells. This increase was prevented by Kasugamycin, suggesting that 80S translation in gametes was more inaccurate than in vegetative cells. The possible significance of these changes occurring during gametogenic differentiation is discussed in light of the importance of a modulation of translational accuracy at particular stages of the life cycle in other lower eukaryotes.Abbreviations Hm
Hygromycin B
- Pm
Paromomycin
- Ks
Kasugamycin
- CAP
Chloramphenicol
- OEE
Oxygen evolving enhancer 相似文献
9.
本文概述了在杀虫剂定量分析中产生误差的原因与减免方法,介绍了对分析方法及分析结果的评价指标及杀虫剂产品标准中的一般要求。 相似文献
10.
目的 探讨针吸活检诊断肺癌的准确性和应用价值。方法 CT引导下对肺部病变进行针吸活检术,针吸获得物制成涂片,对有组织块的标本进行常规石蜡包埋切片,所有标本均HE染色。收集有术后组织学对比的81例病例结果进行回顾性分析。结果 穿刺涂片定性诊断准确率85.2%(69/81),穿刺组织切片为86.2%(56/65),两者结合为91.4%(74/81)。穿刺组织切片对肺癌分型诊断准确率为94.6%(53/56),比穿刺涂片的69.6%(48/69)高(P〈0.01)。结论 细针穿刺涂片与穿刺组织切片的诊断准确性均较高,后者对肺癌的分型有更高的应用价值。 相似文献