数字减影血管造影中双能量减影技术

双能量减影技术是在进行兴趣区（ＲＯＩ）血管造影时。同时使用两种不同的管电压取得两帧图像,作为减影对进行减影。本文运用数学物理方法分析骨组织和软组织在高电压和低电压的减影特点,定量求出骨组织和软组织的厚度。双能量减影要求管电压在短时间内进行切换,难度较高,目前在临床上尚未普及。     

数字减影血管造影中双能量减影技术

双能量减影技术是在进行兴趣区(ROI)血管造影时.同时使用两种不同的管电压取得两帧图像,作为减影对进行减影.本文运用数学物理方法分析骨组织和软组织在高电压和低电压的减影特点,定量求出骨组织和软组织的厚度.双能量减影要求管电压在短时间内进行切换,难度较高,目前在临床上尚未普及.     

基于FPGA的实时数字血管减影系统

介绍了一种基于FPGA的实时数字血管减影系统.重点介绍了在数字血管减影过程中图像对数放大、减影、像素移位以及最大充盈等特殊要求的实现.该系统工作稳定,可靠地实现了X光图像1024×1024大小每秒30帧的实时减影处理,并可期望短期内应用于临床.     

一种基于查找表算法的数字减影血管造影系统

查找表算法在数字信号处理中已有广泛的应用，但在数字减影血管造影术中的应用却报道不多。本文讨论了不同查找表算法对数字减影血管造影图像的影响。结果表明：使用不同的输出查找表算法，会得到不同效果的数字减影血管造影图像。通过分析与比较，我们认为：在图像的后处理方面，应用查找表算法可以进一步改善数字减影血管造影图像的质量。     

排除模板迭代算法在数字减影血管造影中的应用

本文基于ＤＳＡ图象中由于选影剂的影响存在灰度差别的特点，提出了一种新的匹配算法－－排除板迭代算法，成功地实现了ＤＳＡ图象中的运动伪象和灰度伪象的校正。在我们的算法中利用排除模板将存在显著灰度差别的ＤＳＡ序列图像转换为可以 利用古典匹配算法的序列图象，而且在用排除模板进行匹配的过程中，逐次迭代，直至最佳匹配状态。整个算法实现了全自动，且匹配速度快，搜索范围大，精度可达１个象素点。实验结果表明，此方法     

Philips Allura Xper FD10数字减影血管造影伪影分析及排除

正故障现象:Philips Allura xper FD10数字化血管机在投入使用后的前4年图像质量一直非常清晰,但之后显影图像下方突然会发白或黑,并伴有条纹,且故障的发生无规律,也未报错误代码,伪影产生的位置也不固定,先是出现在显示器的下方,继而是图像整个下方,到最后仅剩右上方未累及。故障分析及处理:显示屏的图像显示不正常,若X线系     

Siemens Artis Zee系列数字减影血管造影系统常见故障1例

1 故障现象 Siemens Artis Zee系列数字减影血管造影系统( digital subtraction angiography, DSA )在使用过程中,不能进行摄影采集,只能进行X线透视.同时,检查室内参考图像显示屏底侧区域的信息栏显示"Bypass",控制室内实时图像显示屏右侧区域的各个曝光参数变灰,且不能被修改.     

数字减影血管造影对窦汇区结构的研究

目的　应用数字减影血管造影（DSA）评估窦汇区的解剖结构并探讨其临床意义。 方法　本研究选取203例患者全脑DSA术影像（选择性双侧颈动脉+椎动脉造影）。观察窦汇区及周围各窦形态,包括上矢状窦汇入横窦,和直窦汇入横窦的形式,两侧横窦的大小及分流类型,两侧横窦交通情况和枕窦的出现率。 结果　上矢状窦汇入横窦的方式可分4型,居中型：30.0%（61例）;双分支型：28.6%（58例）;偏右型：35.0%（71例）;偏左型：6.4%（13例）。直窦汇入横窦的方式分3型,居中型：68.0%（138例）;偏右型：18.2%（37例）;偏左型：13.8%（28例）。两侧横窦的分流方式可分5型：对称分流型36.4%（74例）;主要右侧分流型48.8%（99例）;主要左侧分流型5.9%（12例）;单一右侧分流型6.9%（14例）;单一左侧分流型2.0%（4例）。 结论　DSA是一种准确、可靠的评估窦汇区解剖结构的检查,能为静脉窦疾病的诊断和鉴别诊断以及部分头颈部手术方式的选择提供重要帮助。     

新西兰大白兔脑动脉系统的数字减影血管造影成像

目的研究新西兰大白兔脑动脉系统的特点,为建立兔脑血管疾病模型奠定基础。方法新西兰大白兔20只,采用数字减影血管造影(DSA)方法,通过新西兰大白兔股动脉将微导管导入颈内动脉近端造影,分析新西兰大白兔脑动脉系统解剖。结果颅内前后循环系统显影清楚;新西兰大白兔具有与人类相似的脑动脉系统。结论超选择性脑血管造影有利于更好地显示兔脑前后动脉系统,新西兰大白兔脑动脉系统与人类相似,为建立兔脑动脉系统血管疾病模型提供较详细的影像学基础。     

数字减影血管造影图像数据备份存储方式探讨

目的探讨适合数字减影血管造影（DSA）图像备份存储的最简便和最实惠的存储方式。方法将429例具有完整临床资料患者的DSA图像资料进行光盘刻录、图像存储和传输系统（PACS）存储和USB移动存储。对3种方法的备份耗费的时间、调阅所需时间、所耗费用、操作的简便性及图像质量进行比较。结果USB移动储蓄的备份所需时间、调阅所需时间、费用、每例患者备份成本明显低于前两种方法，而且操作简单、图像质量好。结论USB移动存储是最简便和最实惠的DSA图像数据存储方式，可作为常规方法加以推广。     

Relationship Between the Contrast Effects of Raw Data Projection Images from Three-Dimensional Digital Subtraction Angiography and the Optimal Volume Rendering Parameters

Volume rendering (VR) is a technique commonly used for the reconstruction of three-dimensional (3D) digital subtraction angiography (DSA) images, and the rendering parameters greatly affect the characteristics of the 3D image. This study aimed to test whether the optimal VR parameters for 3D DSA could be estimated from the contrast effects in rotational two-dimensional (2D) DSA images acquired using 3D DSA. Simulated blood vessels filled with various concentrations of contrast medium were scanned, and the 3D DSA data sets were reconstructed. The syngo AX vessel analysis software that was able to analyze 3D DSA VR image was used for objective measures. Raw data projection images of the 3D DSA data sets in which the mean diameter was calculated as a true value by the software at nine different thresholds for vessel segmentation were selected. In each image set, five images of all 133 rotational 2D DSA images were selected, and the contrast-enhanced area was extracted using a region-growing algorithm. Mean values and standard deviations of each contrast-enhanced area were calculated, and as the thresholds for vessel segmentation of the software increased by 500 every time, significant differences were observed in the mean values (P < 0.01). This optimal threshold can be applied to the window settings of the VR technique. Therefore, the optimal VR parameters for 3D DSA may be determined by analyzing the contrast effects of the raw data projection images, and user-dependent over- and underestimations of 3D DSA VR images also may be prevented.     

A novel real-time PCR system for simultaneous detection of human viruses in clinical samples from patients with uncertain diagnoses

A novel simultaneous detection system for human viruses was developed using a real-time polymerase chain reaction (PCR) system to identify causes of infection in clinical samples from patients with uncertain diagnoses. This system, designated as the "multivirus real-time PCR," has the potential to detect 163 human viruses (47 DNA viruses and 116 RNA viruses) in a 96-well plate simultaneously. The specificity and sensitivity of each probe-primer set were confirmed with cells or tissues infected with specific viruses. The multivirus real-time PCR system showed profiles of virus infection in 20 autopsies of acquired immunodeficiency syndrome patients, and detected frequently TT virus, cytomegalovirus, human herpesvirus 6, and Epstein-Barr virus in various organs; however, RNA viruses were detected rarely except for human immunodeficiency virus-1. Pathology samples from 40 patients with uncertain diagnoses were examined, including cases of encephalitis, hepatitis, and myocarditis. Herpes simplex virus 1, human herpesvirus 6, and parechovirus 3 were identified as causes of diseases in four cases of encephalitis, while no viruses were identified in other cases as causing disease. This multivirus real-time PCR system can be useful for detecting virus in specimens from patients with uncertain diagnoses.     

Biomarkers of immune tolerance in liver transplantation

The liver exhibits intrinsic immune tolerogenic properties that contribute to a unique propensity toward spontaneous acceptance when transplanted, both in animal models and in humans. Thus, in contrast to what happens after transplantation of other solid organs, several years following liver transplantation a significant subset of patients are capable of maintaining normal allograft function with histological integrity in the absence of immunosuppressive drug treatment. Significant efforts have been put into identifying sensitive and specific biomarkers of tolerance in order to stratify liver transplant recipients according to their need for immunosuppressive medication and their likelihood of being able to completely discontinue it. These biomarkers are currently being validated in prospective clinical trials of immunosuppression withdrawal both in Europe and in the United States. These studies have the potential to transform the clinical management of liver transplant recipients by mitigating, at least in part, the burden of lifelong immunosuppression.