CT机应用质量检测与分析

对全省２７０台ＣＴ机的应用质量检测结果进行了科学的分析与总结，并对目前卫生部有关ＣＴ机应用质量检测与评审的暂行规范进行探讨，建议将伪影这一重要影像指标列入评审项目，同时对新安装ＣＴ机的验收检测进行讨论。指出厂家有高估空间分辨率倾向，并建议不同类型医院应因地制宜地选择实用普及型、临床应用型或临床研究型ＣＴ机。     

江西省X射线诊断设备性能现状分析

目的:了解2008年江西省 X 射线诊断设备性能检测现状,为进一步开展全省 X 射线诊断设备性能检测打好基础。方法:使用 X 射线设备质量控制检测系统对江西省11个地区377台X射线摄片机、180台计算机X射线摄影(CR)机进行检测。结果:各项指标均合格的X射线摄片机、计算机X射线摄影机分别占同类检测总台数的43%、64%。结论:江西省 X 射线摄片机、计算机X射线摄影机存在问题严重,定期进行性能检测是十分紧迫和必要的。     

便携式血糖仪质量管理检测分析

目的对苏州市吴江区第五人民医院便携式血糖仪的临床使用进行质量检测和管理,规范血糖仪的质量管理体系。方法对便携式血糖仪进行品牌内一致性评价、稳定性评价及正确性验证。科室检测人员参加全院的培训学习,参加苏州市检验中心室间质量评价,与未参加室间质量评价的科室仪器比对验证正确度。结果 3家参加品牌内一致性评价的便携式血糖仪,检测结果一致性较高。对选择的1家公司提供的10台便携式血糖仪进行检测后稳定性评价合格,与生化仪比对结果后验证合格。参加苏州市检验中心便携式血糖仪室间质量评价3年,结果均合格,以此为标准比对在用其他血糖仪时除一台不合格遭淘汰其余均合格。结论经过几年的各项严格管理,各科室间的便携式血糖仪检测结果具有了可比性,管理质量有了显著提高,收效明显。     

临床POCT检测项目质量管理体系的建立与实践

目的通过临床即时检测(POCT)检测项目质量管理体系建立与实践,保证其结果的准确性与及时性。方法成立临床POCT管理小组,制定覆盖临床POCT检测全过程的质量管理办法,包括项目的申请与审批、制定操作标准和质量管理规范,检测人员的资质确定与授权并定期考核评价,对全院各POCT仪实行准入制与档案化管理以及定期综合评价等方式。结果质量管理体系运行首月取消了开展不合适的2台POCT仪器及相应的检测项目,随后及时淘汰了5台性能不合格的POCT仪器,并在运行一年后将全院POCT仪器的室内质控、室间质评开展率和合格率及比对试验合格率均提升至100%。结论通过建立并实施临床POCT检测项目质量管理体系,有效地保证了检测结果的准确性与及时性,保障了检测质量和医疗安全。     

65台便携式血糖仪与全自动生化分析仪血糖测定结果的比对分析

目的对本院各科室便携式血糖仪与检验科全自动大型生化分析仪血糖检测结果进行比对、分析,以期建立可靠的血糖仪质量保证体系,为临床提供准确的检测结果。方法分别抽取血糖浓度为高、中、低水平的5份肝素抗凝全血用血糖仪和全自动生化分析仪各检测3次,并对结果进行比对分析。结果该批65台血糖仪的准确性合格率为95.4%(62/65);3台不合格的血糖仪中有2台来自雅培公司、1台来自强生公司。65台血糖仪对含有不同血糖浓度的样本进行重复检测,共有8台血糖仪的重复性检定不合格,合格率为87.7%。结论定期对便携式血糖仪检测结果进行比对并建立和实施有效的质量保证体系是保证便携式血糖检测结果准确可靠的必要前提。     

71台便携式血糖仪与大型生化分析仪血糖测定结果的比对分析

目的建立健全的血糖仪质量保证体系,定期进行血糖仪检测结果与检验科大型生化分析仪检测结果的比对与评估,保证临床血糖仪测定结果的准确性。方法分别抽取高、中、低水平5个不同浓度的肝素抗凝血用血糖仪和生化分析仪各测定3次,并对结果进行比对分析。结果 71台血糖仪中除2台雅培血糖仪准确性比对结果不合格外,其余69台便携式血糖仪准确性的比对结果合格,合格率达97.2%。71台血糖仪重复测定不同水平血糖时,共有11台血糖仪的重复性不合格,合格率为84.5%。结论建立规范的管理体系和切实落实质量保证措施是血糖仪检测结果准确可靠的必备条件。     

便携式血糖仪与全自动生化分析仪血糖结果的比对分析

对31台便携式血糖仪进行重复性试验,并将其检测结果与全自动生化分析仪检测结果进行比对。结果全部血糖仪对5个样本的重复性测试均合格;血糖仪与生化仪比对试验中,除2台不合格血糖仪比对结果偏差>20%外,其他血糖仪所有比对结果偏差均<20%。大部份便携式血糖仪测定结果可靠,符合临床要求,与检验科生化仪血糖测定结果具有可比性。     

全自动酶免分析系统的期间核查管理

目的探讨期间核查管理在全自动酶免分析系统中的应用。方法在酶免分析系统的2次校准或检定时间间隔中期,采取多种核查方案对分析系统的性能进行核查,确认其是否满足检测性能要求。结果留样再测和2台或多台设备间的比对结果测量均值<±10%、批间变异<20%为核查通过,实验室间比对和利用血清盘再测结果与目标结果相符。结论有效的期间核查管理对于预防和发现不合格测量设备的误用具有重要的意义。     

质量控制规则软件在定量检测室间质量评价数据分析中的应用

室间质量评价是质量评价和改进的重要途径之一,但实验室往往只对不合格的数据进行分析。选择合适的质量控制规则,可以对不合格数据的误差来源以及合格数据存在的潜在问题进行分析;文章分析了已开发出的相关质量控制规则软件,用于分析室间质评结果、评价方法学性能、查找误差来源。     

上海市M-H培养基抽样调查分析

目的　对所抽查的M H培养基质量进行调查分析。方法　通过对M H培养基作一般性状(厚度、pH值)、无菌试验以及性能检测以判断其质量。结果　所抽查的4种品牌成品培养基(15个批号)的一般性状与无菌试验结果均合格;性能检测中二价阳离子浓度全部全格;有2种品牌4个批号的M H培养基胸腺嘧啶或胸腺嘧啶核苷含量不合格。3种品牌(8个批号)的干粉自制培养基除厚度外(厚度<4mm的占18% ),pH值、无菌试验、二价阳离子浓度均合格;胸腺嘧啶或胸腺嘧啶核苷均不合格。结论　所抽的4种品牌成品培养基中只有2种M H培养基质量符合要求,市售3个品牌的水解酪蛋白干粉不适合制备M H培养基。     

Assessment of Image Quality and Dosimetric Performance of CT Simulators

BackgroundCT simulator for radiation therapy aims to produce high-quality images for dose calculation and delineation of target and organs at risk in the process of treatment planning. Selection of CT imaging protocols that achieve a desired image quality while minimizing patient dose depends on technical CT parameters and their relationship with image quality and radiation dose. For similar imaging protocols using comparable technical CT parameters, there are also variations in image quality metrics between different CT simulator models. Understanding the relationship and variation is important for selecting appropriate imaging protocol and standardizing QC process. Here, we proposed an automated method to determine the relationship between image quality and radiation dose for various CT technical parameters.Material and MethodThe impact of scan parameters on various aspects of image quality and volumetric CT dose index for a Philips Brilliance Big Bore and a Toshiba Aquilion One CT scanners were determined by using commercial phantom and automated image quality analysis software and cylindrical radiation dose phantom.Results and DiscussionBoth scanners had very similar and satisfactory performance based on the diagnostic acceptance criteria recommended by ACR, International Atomic Energy Agency, and American Association of Physicists in Medicine. However, our results showed a compromise between different image quality components such as low-contrast and spatial resolution with the change of scanning parameters and revealed variations between the two scanners on their image quality performance. Measurement using a generic phantom and analysis by automated software was unbiased and efficient.ConclusionThis method provides information that can be used as a baseline for CT scanner image quality and dosimetric QC for different CT scanner models in a given institution or across sites.     

GE各系列CT机主要性能指标的实验研究

目的：探讨GE各系列CT机主要性能指标的实验研究。方法：CT机质量控制检测是CT机应用中的重要环节，笔者采用Victoreen公司生产的AAPM体模，4000M^ 剂量仪及10cm笔型电离室对GT各系列17例CT机的十项主要性能指标进行了检测。结果：标准算法下10种低档CT的空间分辨率为1．0mm，7种中高档机型可达0．75mm，高分辨率算法下，LightspeedQx/I型可达0．4mm，而8800型却只有0．75mm，所抽检的全部CT其密度分辨率均在0．6％，3．5mm以内，最好的可小于2．5mm。结论：高档CT质量优于普通CT主要表现为，更高的空间分辨率，密度分辨率及轴向分辨率，更快的扫描速度，更多的扫描层数，以及功能更丰富的重要软件。     

Coronary CT Angiography for the Detection of Obstructive Coronary Artery Disease

Contemporary CT scanners offer high temporal and spatial resolution, permitting visualization of the rapidly moving heart and coronary arteries. The imaging of coronary artery lumen and detection of obstructive coronary artery disease is feasible with 64-detector-row and higher generation CT scanners. The diagnostic accuracy of coronary CT angiography as compared to invasive coronary angiography is good (sensitivity of 85%–100%, specificity of 85%–99%). The major strength of coronary CT angiography is the high negative predictive value (96% to 99%) that permits excluding significant coronary artery stenosis with high accuracy, when optimal image quality is achieved. Therefore, coronary CT angiography is an appropriate diagnostic test for a selected patient population with a low to intermediate probability of coronary artery disease.     

Performance evaluation of a C-Arm CT perfusion phantom

Purpose Brain perfusion measurement in stroke patients provides important information on the infarct area and state of involved tissue. Interventional C-Arm angiography systems can provide perfusion measurements. A CT perfusion phantom was developed for C-Arm perfusion imaging to test and evaluate this method and to aid in the design and validation of scan protocols. Methods A phantom test device was designed based on the anatomy of the human head. Four feeding arteries divided into sixteen sub-branches that lead into a sintered board simulating brain parenchyma. Perfusion measurements were performed using two conventional clinical CT scanners as the gold standard and with a C-Arm CT system to test and compare the implementations. The phantom’s input parameters, contrast medium and flow properties were varied. A cerebral perfusion deficit was simulated by occlusion of a feeding artery tube. Results CT perfusion maps of the sintered board brain tissue surrogate were computed and qualitatively compared for both conventional CT and C-Arm CT systems. A characteristic flow pattern of the tissue board was identifiable in both modalities. The characteristic flow pattern of the resulting perfusion maps is reproducible. The calculated flow and volume were directly related. Conclusions A new CT perfusion phantom was developed and tested. This phantom is an appropriate model for CT-based tissue perfusion measurements in both conventional CT scanners and C-Arm CT scanners. The influence of input parameter changes can be visualized. Perfusion deficits after occlusion of a feeding artery are readily simulated and identified with CT.     

多层螺旋CT血管成像评价冠状动脉血管旁路移植术

目的评价多层螺旋CT(MSCT)冠状动脉成像对冠状动脉桥血管的临床价值。方法28例患者的69条冠状动脉桥血管接受16层和64层螺旋CT冠状动脉成像。对桥血管成像进行影像质量评估,使用多元线性回归方法评估患者心率、心率波动幅度、呼吸运动以及不同CT扫描机对冠状动脉成像质量的影响。其中10位患者26条桥血管的CT血管成像结果与冠状动脉血管造影结果进行对比。结果呼吸运动伪影与冠状动脉桥血管成像质量呈负相关,相关系数为-0.838。64层CT扫描机的影像质量高于16层CT扫描机的影像质量。以CAG结果为参考标准,MSCT冠脉成像诊断桥血管及吻合口狭窄的特异性和敏感性分别为95.7%和92.3%。结论MSCT可以提供可靠的冠状动脉桥血管影像以及较高的诊断准确性。     

Radiation exposure and dose reduction measures in cardiac CT

Noninvasive visualization of the heart by CT is highly accurate and useful, but its association with ionizing radiation and the potential risk of cancer induction has raised concerns. Dose-saving algorithms, new CT scanners, and scanning techniques have been developed to effectively reduce the amount of radiation exposure without deterioration of image quality. Furthermore, additional strategies for dose reduction can be pursued in daily practice following the ALARA (as low as reasonably achievable) principle. However, there still is a high additional dose-saving potential in a consequent application of dose reduction measures, and we recommend individually adapted scan protocols to obtain cardiac CT studies with optimal diagnostic image quality and lowest possible radiation dose.     

Criteria and scheduling of quality control of B-mode and doppler ultrasonography equipment

Periodic quality control (QC) for ultrasound scanners checks their overall performance, reducing the risk of inaccurate diagnoses. Data from routine annual QC activity were analyzed to optimize the scheduling and the criteria of further QC programs. Among all the ultrasound scanners (68 transducers) in use at the Regional Medical Department of the Aosta Valley, which are currently tested, 48.6% showed problems, mainly (35.3%) related to defects detectable by physical and mechanical inspection. Nearly two‐thirds of these problems impacted QC parameters. Failures were significantly related to the workload and to the “technological level” of the equipment. QC scheduling should therefore include a daily/weekly physical inspection in addition to a more complete, objective and software algorithms‐based test, the frequency of which should be tailored on the basis of the equipment characteristics. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012     

Availability and Quality of Computed Tomography and Magnetic Resonance Imaging Equipment in U.S. Emergency Departments

Objectives:  The objective was to determine the availability and quality of computed tomography (CT) and magnetic resonance imaging (MRI) equipment in U.S. emergency departments (EDs). The authors hypothesized that smaller, rural EDs have less availability and lower-quality equipment.
Methods:  This was a random selection of 262 (5%) U.S. EDs from the 2005 National Emergency Department Inventories (NEDI)-USA ( http://www.emnet-usa.org/ ). The authors telephoned radiology technicians about the presence of CT and MRI equipment, availability for ED imaging, and number of slices for the available CT scanners. The analysis was stratified by site characteristics.
Results:  The authors collected data from 260 institutions (99% response). In this random sample of EDs, the median annual patient visit volume was 19,872 (interquartile range = 6,788 to 35,757), 28% (95% confidence interval [CI] = 22% to 33%) were rural, and 27% (95% CI = 21% to 32%) participated in the Critical Access Hospital program. CT scanners were present in 249 (96%) institutions, and of these, 235 (94%) had 24/7 access for ED patients. CT scanner resolution varied: 28% had 1–4 slice, 33% had 5–16 slice, and 39% had a more than 16 slice. On-site MRI was available for 171 (66%) institutions, and mobile MRI for 53 (20%). Smaller, rural, and critical access hospitals had lower CT and MRI availability and less access to higher-resolution CT scanners.
Conclusions:  Although access to CT imaging was high (>90%), CT resolution and access to MRI were variable. Based on observed differences, the availability and quality of imaging equipment may vary by ED size and location.     

Design and Validation of Synchronous QCT Calibration Phantom: Practical Methodology

Introduction

Quantitative computed tomography (QCT) can supplement dual x-ray absorptiometry by enabling geometric and compartmental bone assessments. Whole-body spiral CT scanners are widely available and require a short scanning time of seconds, in contrast to peripheral QCT scanners, which require several minutes of scanning time. This study designed and evaluated the accuracy and precision of a homemade QCT calibration phantom using a whole-body spiral CT scanner.