CR系统伪影的分析和解决方法

目的：对CR系统图像伪影原因的分析，探讨预防和消除伪影产生的方法。方法：对82例伪影进行回顾性分析。结果：产生伪影的原因有：(1)成像板伪影；(2)系统硬件造成的伪影；(3)后处理造成的伪影；(4)记忆伪影；(5)滤线栅伪影。结论：在工作中，正确使用和维护CR系统，可以减少CR图像的伪影。     

DR胸部立位摄影出现滤线栅状伪影的分析与处理

故障现象New Medical(新医)公司750型平板探测器在胸部立位摄影时图像出现"滤线栅"状伪影。"滤线栅"状伪影在成人胸部立位摄影图像中会偶尔出现,而儿童胸部立位摄影图像中全部出现。故障分析与检修New Medical公司750型平板探测器使用的是活动式滤线栅。根据滤线栅原理,在发出曝光信号后,滤线栅应先运动直至X射线曝光结束后再停止,并在运动过程中吸收散射线,达到提高图像质量的目的。本则胸部     

影响CR软拷贝影像质量的相关因素

尽图 9　腹部CR照片 ,其上下两侧因在X线拍摄时缩光器未打开 ,而整个图像没有压缩 ,且呈对称性白色。　图 1 0　a)髌骨轴位的CR照片 ,呈毛玻璃状 ;b)用Unpress对图像进行处理后显示出清晰的图像。　图 1 1　装有IP的暗盒放在机房内 ,因X线散射所致 ,大片状白色影是另一个暗盒在其上方 ,造成周边感光。伪影 1 3例 ,图像压缩 1 8例 ,毛玻璃状伪影 53例 ,扫描中断伪影2例 ,双影像伪影 2 5例 ,图像变形 1例 ,图像未擦除产生重叠伪影 2例 ,暗盒扣伪影 1例 ,乳腺沙粒状伪影 3例 ;未用滤线栅 (如颈椎正位未用自加断层摄影、站立位腹部平片 ) 85…     

混叠效应对数字化X线影像的影响及其分析

目的 探讨数字X线摄影中混叠效应的产生原因及其对影像质量的影响。方法 使用Kodak CR900系统分别对矩形波测试卡和固定滤线栅成像。测试卡铅条在平行于激光扫描方向和呈45°角的放置方式下分别成像,观察两种影像对分辨率测试卡的显示情况。使滤线栅铅条的方向在平行和垂直于激光扫描方向时分别成像,在显示器上使用不同的放大率对滤线栅影像进行观察,并比较两种影像外观的差异。结果 测试卡影像上,3.93线对/mm以上频率的铅条影无法相互分辨,因此尼奎斯特频率为3.93 LP/mm。但在测试卡45°放置的影像中,频率为4.86 LP/mm的铅条仍能相互分辨。滤线栅铅条平行于成像板的激光扫描方向时,最终影像中显示出明显的条纹影。在显示器上使用不同的放大率观察时,栅条形成的条纹影宽度和方向都发生明显变化。铅条与激光扫描方向垂直时影像中的条纹影显著减弱。结论 CR应用中混叠效应会对数字影像产生不利影响,应根据设备的极限分辨率选择适当的固定滤线栅,栅频率应大于尼奎斯特频率。在摄影中,滤线栅的铅条方向应与成像板的激光扫描方向相垂直。在显示器上观察固定滤线栅摄影影像时,建议使用原始图像的整数倍的放大率。     

影响计算机X线摄影质量的常见问题

目的 探索计算机X线摄影（CR）中存在的实际问题，保证CR的图像质量，提高诊断水平，促进数字化影像标准的制订。方法 北京市内9家三级甲等医院提供的107张有问题的CR照片，组织放射科的医师、技师、工程技术人员20余名对其出现问题的现象、原因逐片分析、讨论、记录和统计。结果 107张有问题的CR照片，属于人为与外在因素造成的现象有36张（33．64％）；成像板（IP）在读取过程或数据传输过程中出现的伪影29张（27．10％）；与IP相关原因所致图像伪影15张（14．02％）；摄影条件选择不当造成图像质量不佳13张（12．15％）；打印机故障造成的废片9张（8．41％）；后处理不当造成图像假象或质量不佳5张（4．67％）。通过对107张CR废片原因分析，60．74％的原因是因为工作不细心，操作不规范所致，35．51％是CR技术中遇到的新问题，其他是后处理不当造成。结论 加强责任心，规范操作规程，制订数字化影像质量标准，加强新技术理论学习，合理应用后处理功能，是保证CR图像质量和提高诊断水平的重要环节。     

X线照片伪影产生原因分析

Ｘ线照片伪影产生原因分析刘良厚Ｘ线照片伪影是一种较为常见的现象。由于ｘ线胶片的理化特性以及保管使用不当等原因，常可出现不同的伪影。这些伪影一般分为两大类：黑色伪影和白色伪影。黑色伪影在物理学上是一种高密度影像（光学密度）。ｘ线胶片局部银离子曝光显影后...     

CR临床应用的体会

目的：通过近一年CR操作，就操作经验作一介绍，共同道参考。材料与方法：收集3万多病人资料，采用两台美国GE-VR500MA高频X线机及美国柯达CR-900成像系统。结果：技术选择：虽然CR有较大的宽容度但对摄片条件仍有一定的限度，对各部位摄片条件也要适当选择。经过一年对3万多病人的摄片条件，总结出曝光参数如下：胸部正位90-100KV，320-500mA，20ms，6．3-10mAs，胶片距120cm，用滤线栅。腹部，80-90KV，500mA，80ms，40mAs，胶片距100cm，用滤线栅等。IP板的选择：在摄片时，对IP板大小规格的选择应适当，如选择不当会导致影像的失真，特别是对小关节的摄影。结论：（1）CR能减少医技人员及病人的辐射量。（2）使用方便，缩短工作流程，提高工作效率，同时减少病人重拍，降低废片率。（3）CR具有强大的图像后处理功能，可获取不同组织层次的图像。（4）图像存储，光盘刻录，减少档案库压力。（5）能与CT、MR、DSA、计算机网络连接，达到资源共享的目的。     

计算机X线摄影图像质量控制

目的：改善计算机X线摄影（CR）的图像质量，提高CR系统的稳定性。方法：分析本科室CR图像密度不均匀的原因，测试本科室CR系统，再进行PMT（光电倍增管）校正。测试本地6家医院7台不同机型的CR系统，然后制成胶片并用密度仪分别检测其密度。结果：所有CR图像密度均有不同程度的误差。测试中密度误差小于0．5的有2台，占测试机器的29％，密度误差大干0．5有5台，占测试机器的71％。经PMT校正后本科室CR图像密度误差从0．51下降到0．12。结论：适时监测CR图像密度误差，及时进行PMT校正是保证CR系统稳定运行和提高CR图像质量的有效办法。     

AGFA CR系统故障检修一则

故障现象 CR像上出现较多的黑色细线伪影. 故障分析与检修 首先在CR后处理工作站显示器上观察图像,发现图像上已有黑线伪影,可排除激光相机故障.再仔细观察多幅图像上的黑色细线伪影,发现两个特点:一是黑线伪影随机分布,出现的位置、长度及数量不固定,可排除由IP板损坏所致;二是黑线伪影总是与IP板在扫描仪中扫描时走行的方向垂直,即与激光扫描线的方向一致.初步考虑系SOLO扫描仪故障.     

CRX线机的日常维护和定期检测

CR的最大特点是用高灵敏、高分辨和动态范围较宽的成像板（IP）代替常规X线胶片，并采用激光读片法将模拟量的图像转换为数字量，利用计算机加以处理。使之在提高像质消除动态伪影方面效果突出，而且可将图像信息输入到综合影像诊断系统中。所以维修技术人员做好日常维护和检测工作，能降低设备故障率，延长设备使用寿命，保证设备在最佳状态下运行。充分发挥其应有效能，提供可靠保障。     

Knee injury and Osteoarthritis Outcome Score (KOOS) - validation of a Swedish version

The Knee injury and Osteoarthritis Outcome Score (KOOS) is a self-administered instrument measuring outcome after knee injury at impairment, disability, and handicap level in five subscales. Reliability, validity, and responsiveness of a Swedish version was assessed in 142 patients who underwent arthroscopy because of injury to the menisci, anterior cruciate ligament, or cartilage of the knee. The clinimetric properties were found to be good and comparable to the American version of the KOOS. Comparison to the Short Form-36 and the Lysholm knee scoring scale revealed expected correlations and construct validity. Item by item, symptoms and functional limitations were compared between diagnostic groups. High responsiveness was found three months after arthroscopic partial meniscectomy for all subscales but Activities of Daily Living.     

Endovascular management of carotid-cavernous fistulas

Objective To investigate endovascular treatment of traumatic direct carotid-cavernous fistulas （CCF） and their complications such as pseudoaneurysms. Methods： Over a five-year period, 22 patients with traumatic direct CCFs were treated endovascularly in our institution. Thirteen patients were treated once with the result of CCF occluded, 8 twice and 1 three times. Treatment modalities included balloon occlusion of the CCF, sacrifice of the ipsilateral internal carotid artery with detachable balloon, coll embolization of the cavernous sinus and secondary pseudoaneurysms, and covered-stem management of the pseudoaneurysms. Results All the direct CCFs were successfully managed endovascularly. Four patients developed a pseudoaneurysm after the occlusion of the CCF with an incidence of pseudoaneurysm formation of 18.2% （4/22）. A total number of 8 patients experienced permanent occlusion of the ICA with a rate of ICA occlusion reaching 36.4% （8/22）. Followed up through telephone consultation from 6 months to 5 years, all did well with no recurrence of CCF symptoms and signs. Conclusion Traumatic direct CCFs can be successfully managed with endovascular means. The pseudoaneurysms secondary to the occlusion of the CCFs can be occluded with stent-assisted coiling and implantation of covered stents.     

The acutely limping child

Acute limping may be the result of multiple pathologies in children. The differential diagnosis varies based on the age of the child. Irrespective of age, the initial imaging work-up includes AP and frog leg radiographs of the pelvis and ultrasound; MRI may sometimes be helpful. In children less than 3 years, infections and trauma are most frequent. MRI is the imaging modality of choice when osteomyelitis is clinically suspected. Between the ages of 3 and 10 years, transient synovitis of the hip and Legg-Calvé-Perthes disease are main considerations but infection, inflammation and focal bony lesions are also considered. In children over 10 years, slipped capital femoral epiphysis also is considered.     

Do Balance Board Training Programs Reduce the Risk of Ankle Sprains in Athletes?

Introduction Ankle sprains are the most common musculo-skeletal injury that occurs in athletes,particularly in sports that require jumping and landing on one foot such as soccer,and basketball(1-4).These injuries often result in significant time loss from participation,long-term disability,and have a major impact on health care costs and resources(5-8).     

High Intensity Interval Training:New Insights

KEY POINTS ·High-intensity interval training(HIT)is characterized by repeated sessions of relatively brief，intermittent exercise.often performed with an“a11 out”effort or at an intensity close to that which elicits peak oxygen uptake(i.e.，≥90%of VO2 peak).     

Developmental validation of the PowerPlex(®) ESI 16 and PowerPlex(®) ESI 17 Systems: STR multiplexes for the new European standard

In response to the ENFSI and EDNAP groups’ call for new STR multiplexes for Europe, Promega^® developed a suite of four new DNA profiling kits. This paper describes the developmental validation study performed on the PowerPlex^® ESI 16 (European Standard Investigator 16) and the PowerPlex^® ESI 17 Systems. The PowerPlex^® ESI 16 System combines the 11 loci compatible with the UK National DNA Database^®, contained within the AmpFlSTR^® SGM Plus^® PCR Amplification Kit, with five additional loci: D2S441, D10S1248, D22S1045, D1S1656 and D12S391. The multiplex was designed to reduce the amplicon size of the loci found in the AmpFlSTR^® SGM Plus^® kit. This design facilitates increased robustness and amplification success for the loci used in the national DNA databases created in many countries, when analyzing degraded DNA samples. The PowerPlex^® ESI 17 System amplifies the same loci as the PowerPlex^® ESI 16 System, but with the addition of a primer pair for the SE33 locus. Tests were designed to address the developmental validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM), and those of the DNA Advisory Board (DAB). Samples processed include DNA mixtures, PCR reactions spiked with inhibitors, a sensitivity series, and 306 United Kingdom donor samples to determine concordance with data generated with the AmpFlSTR^® SGM Plus^® kit. Allele frequencies from 242 white Caucasian samples collected in the United Kingdom are also presented. The PowerPlex^® ESI 16 and ESI 17 Systems are robust and sensitive tools, suitable for the analysis of forensic DNA samples. Full profiles were routinely observed with 62.5 pg of a fully heterozygous single source DNA template. This high level of sensitivity was found to impact on mixture analyses, where 54–86% of unique minor contributor alleles were routinely observed in a 1:19 mixture ratio. Improved sensitivity combined with the robustness afforded by smaller amplicons has substantially improved the quantity of data obtained from degraded samples, and the improved chemistry confers exceptional tolerance to high levels of laboratory prepared inhibitors.