16层螺旋CT冠状动脉造影中心率对图像质量的影响

对138例疑诊冠心病患者行16层螺旋CT冠状动脉造影（MSCTCA）检查,其中心率〈60次／min者40例（A组）、60～65次／min者30例（B组）、65～70次／min者36例（C组）、〉700次／min者70例（D组）,根据冠状动脉伪影多少及血管连续性评价各组重建图像质量。结果A、B、C、D组左冠状动脉及其分支的检查成功率分别为95％、93．3％、83．3％和50％,右侧冠状动脉分别为90％、93．3％、77．8％和50％,D组各冠状动脉节段检查成功率均显著低于其他三组（P〈0．05）。认为冠状动脉MSCT检查前心率调整〈65次／min即可获得较高的成功率;保持检查过程中心率稳定（变化〈30次／min）有助于提高检查成功率。     

心率及心率波动对256层CT回顾性心电门控冠状动脉成像质量的影响简

目的 探讨心率及心率波动对256层计算机断层扫描（computerized tomography,CT）冠状动脉成像图像质量的影响.方法 150例疑为冠状动脉粥样硬化性心脏病（冠心病）的患者行256层CT回顾性心电门控冠状动脉检查,对直径＞1.5 mm的冠状动脉节段进行评分.根据平均心率分为3组：A组,心率＜65次/min;B组,65次/min～80次/min;C组,心率≥80次/min.比较不同心率组间的图像质量,采用Pearson相关分析方法分析平均心率及心率波动对图像质量的影响,并采用线性回归方程确定需进行干预的心率临界点.结果 在最佳重组时相上,可满足诊断要求的图像占97.9％.冠状动脉总体、右冠状动脉、左前降支及左旋支的图像质量评分与心率显著相关,相关系数分别为0.473、0.425、0.409、0.413（P均＜0.001）,冠状动脉图像质量与心率波动无明显相关（P＞0.05）.不同心率组间冠状动脉图像质量比较,差异有统计学意义（P＜0.05）.当心率＜83.1次/min时,可获得优良的图像质量,而为获取满足临床诊断要求的图像,心率应＜119.1次/min.心率＜65次/min时,舒张期重建的图像质量佳;心率＞71次/min时,收缩期重建的图像质量佳.结论 心率波动对256层CT同顾性心电门控冠状动脉图像质量无显著影响,但心率仍是影响图像质量的一个重要因素;降低心率有助于提高图像质量.     

双源CT两种冠状动脉造影扫描方法及辐射剂量对比研究

目的优化双源CT冠状动脉成像的扫描方案,降低患者冠状动脉成像的辐射剂量。方法分析268例心率规律且小于70次／min双源CT冠状动脉成像患者病例资料,前瞻性心电门控及回顾性心电门控检查患者各134例,观察两者成像质量,比较两者单次扫描CT容积剂量指数（CTDIvol）及剂量长度乘积（DLP）。结果在扫描范围、对比剂种类速率和注射部位完全相同的情况下,前瞻性心电门控组质量评分（3．71±0．52）分,回顾性心电门控组质量评分（3．78±0．36）分,P〉0．05。前瞻性心电门控组和回顾性心电门控组在CTDIvol分别为（14．02±0．02）、（79．50±10．09）mGy;有效辐射剂量分别为（3．38±0．28）、（23．84±4．35）mSv,P均〈0．05。结论在心率规律且小于70次／min的患者行前瞻性心电门控冠状动脉成像,可有效地降低患者的辐射剂量,减轻辐射损伤。     

心率对老年人64层CT冠状动脉造影质量的影响

目的探讨心率对老年人64层CT冠状动脉造影质量的影响。方法回顾性分析137例老年患者64层螺旋CT冠状动脉造影结果。根据检查时心率不同分为三组:A组58例,心率70次/min,平均64次/min;B组55例,心率70～79次/min,平均74次/min;C组24例,心率80～88次/min,平均85次/min。采集的原始图像采用容积再现技术(VRT),多平面重建(MPR),曲面重建(CPR)和最大密度投影(MIP)等后处理技术。冠状动脉主要分支(RCA、LM、LAD、LCX)的CT图像质量采用双盲法、按照5级评分法进行评估,3分以上认为图像质量合格,达到诊断要求。结果图像质量符合诊断要求比率分别为:A组96.6%(224/232),B组92.7%(204/220),C组83.3%(80/96)。经χ2检验,A、B两组之间图像质量合格率无统计学差异(χ2=3.28,P0.05)。结论应用64层螺旋CT进行冠状动脉造影在一定程度内适当放宽对心率的要求(≤80次/min),图像质量仍可基本满足诊断需要,是一种筛查老年人冠心病的安全、有效手段。     

糖尿病合并心血管患者行双源螺旋CT冠状动脉成像安全性护理

目的探究分析糖尿病合并心血管患者行双源螺旋CT冠状动脉成像安全性护理方法及效果。方法选取2018年1月—2019年8月于该院收治的208例行双源螺旋CT冠状动脉成像的糖尿病合并心血管疾病患者作为研究对象,按照随机数字表将患者随机分为两组,对照组104例冠状动脉成像期间给予一般指导,观察组104例冠状动脉成像期间给予安全性护理,比较两组护理效果。结果观察组104例的冠状动脉成像一次成功率95.2%、检查时间5 min内比例93.3%、心率过快发生率4.8%与对照组的冠状动脉成像一次成功率75.0%、检查时间5 min内比例76.9%、心率过快发生率17.3%比较差异有统计学意义(P0.05)。观察组104例的图像质量(1级、2级、3级)优于对照组(P0.05)。观察组护理后的空腹血糖水平低于对照组(P0.05)。观察组104例的护理满意度98.1%大于对照组的82.7%(P0.05)。结论糖尿病合并心血管患者行双源螺旋CT冠状动脉成像时给予安全性护理,可有效提高成像成功率,减少不良反应,提高冠状动脉成像的图像质量。     

老年患者双源CT冠状动脉成像的研究

目的 探讨老年患者采用双源CT冠状动脉成像的图像质量和诊断冠状动脉病变的特点. 方法 200例临床怀疑冠心病者,检查前均未口服倍他乐克准备.分为老年组126例,年龄60～91岁,对照组例74例,年龄38～59岁.比较两组患者的临床特征、平扫及增强扫描的平均心率和屏气时间、平均钙化积分值、图像质量评价及冠状动脉狭窄情况. 结果与对照组比较,老年组胸闷、胸痛、高血压、糖尿病、高血脂和陈旧心肌梗死的发生率明显高于对照组,平均钙化积分值、<50%及≥50%狭窄数均高于对照组(均P<0.01).老年组平扫及增强扫描的平均心率和屏气时间与对照组比较差异无统计学意义,老年组图像质量为1级、2级和3级的冠状动脉节段分别为96.5%、2.3%和1.2%,与对照组(97.1%、2.0%和0.9%)比较,差异无统计学意义(均P>0.05).结论 双源CT冠状动脉成像是一种无创、安伞、简便的方法.在无需口服倍他乐克准备的情况下获得满意的冠状动脉各节段图像,可做为老年患者冠心病常规检查有效方法之一.     

探索64排CT后门控冠状动脉图像质量与心率的关系

目的探讨64排CT后门控冠状动脉图像质量与心率的关系。方法将372例分三组,A组心率70次/min,B组心率70次/min80次/min,C组心率80次/min(心率大于90次/min药物控制),部分数据通过冠脉多期相重组来改善图像质量,最后只对运动幅度相对较大的、较难成像的RCA进行图像质量评价,图像质量评价标准改良分为3个等级(Ⅰ级管腔光整,边缘锐利;Ⅱ级局部少许管腔不光整,不影响诊断;Ⅲ级多处管腔边缘不光整,但可以做出诊断)。结果 64排CT冠脉图像质量随着心率的升高而降低;对于部分高心率(大于80±2次/min),经双扇区的选择及多期相重建,图像质量C组与B组接近,双扇区、时相重建选择虽延长了后处理的时间,但对图像质量明显改善,仍能满足诊断及临床的需求。     

双源CTA在高心率冠心病患者冠状动脉狭窄诊断中的应用观察

目的观察双源CT冠状动脉血管成像（双源CTA）诊断较高心率者（≥75次/m in）冠状动脉狭窄的效果。方法 51例冠心病患者,心率均≥75次/min,均接受双源CTA和传统冠状动脉血管造影（CAG）检查。结果双源CTA、CAG均检出冠状动脉狭窄者94段,均未检出者359段,仅CAG检出者34段,仅双源CTA检出者20段。以CAG结果为金标准,双源CTA诊断高心率冠心病患者冠状动脉狭窄的敏感度为73.44%,特异度为94.72%,符合率为89.34%,阳性预测值为82.46%,阴性预测值91.35%。结论 双源CTA诊断偏高心率冠心病患者（心率≥75次/m in）冠状动脉狭窄（≥50%）效果较好。     

心率对64排螺旋CT冠状动脉成像质量的影响

目的分析心率对64排螺旋CT冠状动脉成像(CCTA)质量的影响。 方法选取2016年9月至2018年6月开封市中心医院行CCTA检查的126例患者,按照扫描时同步记录心电图的最高心率分为≤65次/min组(82例)、66～70次/min组(25例)、>70次/min组(19例),比较3组图像可评价率,并对比初始图像与再重建图像可评价率。 结果≤65次/min组图像可评价率(98.78%)高于>70次/min组(57.89%)(P<0.05);66～70次/min组图像可评价率(92.00%)高于>70次/min组(57.89%)(P<0.05);再重建后图像可评价率93.65%高于初始图像(R波后)83.33%(P<0.05)。 结论心率低于70次/min时图像可评价率较高,高于70次/min时可显著影响图像质量,此时应用心电图编辑、多时相重建、多点重建技术能提高CCTA成像质量。     

心率变化对256层螺旋CT冠状动脉成像质量的影响

目的探讨心率变化对256层螺旋CT冠状动脉成像质量的影响。方法对95例临床怀疑或确诊为冠心病的患者行256层螺旋CT冠状动脉造影检查,入选患者按照心率不同分为3组:第一组为心率≤75次/min,第二组心率为76～100次/min,第三组为心率100次/min。分别对每组图像质量进行评价。结果第一组的图像质量优良率为97.6%,能够满足诊断率为98.6%,第二组图像质量优良率为96.9%,能够满足诊断率为98.5%,第三组图像质量优良率为94.3%,能够满足诊断率为96.8%。结论 256层螺旋CT对高心率的适应性有了明显提高。     

心率及心率波动对64层螺旋CT冠状动脉成像质量的影响

目的回顾性分析心率及心率波动对64层螺旋CT冠状动脉图像质量的影响。方法将129例疑为冠心病的患者行64层螺旋CT冠状动脉检查的原始数据在心动周期的40%～80%时相上进行图像重组。对直径>1.5mm冠状动脉节段进行评分(≤3分为满足临床诊断)。采用Pearson相关分析方法分析平均心率及心率波动对图像质量的影响。结果扫描时所有患者心率33～108次/min,平均62.2次/min。心率波动0.2～46.9次/min,平均4.4次/min。在最佳重组时相上,可满足诊断的图像占93.9%。图像质量与平均心率及心率波动显著相关。心率<69.7次/min及心率波动<15.7次/min时,可获得优良的图像质量;心率<63次/min时,舒张期重组的图像质量佳;心率>67次/min时,收缩期重组的图像质量佳。重组时相窗从舒张期切换至收缩期的心率范围为63～67次/min。结论心率及心率波动对64层螺旋CT冠状动脉图像质量有重要影响,减低心率及心率波动可提高图像质量。     

256层CTA技术在冠状动脉硬化狭窄诊断中的应用价值

目的 探讨256层CT血管成像（CTA）技术在冠状动脉成像及其狭窄诊断中的应用价值.方法 选择临床拟诊或疑诊冠状动脉疾病者400例,均行CTA冠状动脉检查,其中53例行DSA冠状动脉造影;由2名医生对图像质量评价,采用分级评分法评价冠状动脉15节段.结果 CTA显示冠状动脉节段共5 793个,其中评分为4、5分5 691个（98.24％）;与DSA比较,CTA诊断冠状动脉狭窄的准确率为94.33％、特异性为93.75％、敏感性为94.59％.DSA与CTA两种检查方法诊断冠状动脉狭窄一致性较好,Kappa为0.868.256层CTA诊断冠状动脉狭窄,在不同心率患者间差异无统计学意义.结论 256层CTA冠状动脉成像质量较高,可清晰地显示冠状动脉主要节段影像,较为准确地诊断冠状动脉狭窄,特异性、敏感性较好,且不受心率影响.     

128层螺旋CT冠状动脉成像与选择性冠状动脉造影诊断冠心病价值的比较

目的 评价128层螺旋CT(MSCT)冠状动脉成像诊断冠状动脉疾病的价值.方法 对临床怀疑或确诊冠心病的非选择性连续78例患者进行128层MSCT冠状动脉成像,其中有15例患者既往置入冠状动脉支架.以选择性冠状动脉造影结果作为评价标准,探讨128层MSCT在诊断冠状动脉疾病及评价支架后再狭窄的临床价值.结果 基于冠状动脉血管节段分析,879个冠状动脉节段中有821节段(93%)进入统计学分析,128层MSCT诊断冠状动脉病变的敏感性87%,特异性97%,阳性预测值83%,阴性预测值97%.对15例共置入22个支架的患者中,有4个(18%)支架MSCT图像显示支架伪影,图像模糊,未能判断支架内血管腔通畅情况,其余18个支架MSCT结果与选择性冠状动脉造影比较,MSCT诊断支架再狭窄的敏感性为100%,特异性77%,阳性预测值63%,阴性预测值100%.结论 128层MSCT冠状动脉成像对冠状动脉疾病的诊断和支架再狭窄的评价具有较高价值,可以作为一项无创检查技术用于对临床怀疑为冠心病的患者进行筛查.     

Influence of heart rate on the diagnostic accuracy of dual-source computed tomography coronary angiography.

OBJECTIVES: We evaluated the influence of heart rate on image quality and diagnostic accuracy of dual-source computed tomography (DSCT) coronary angiography. BACKGROUND: Multidetector computed tomography (MDCT) coronary angiography has demonstrated an inverse relationship between heart rate and image quality. Dual-source CT provides a higher temporal resolution. METHODS: One hundred patients were studied by DSCT (DEFINITION, Siemens Medical Solutions, Forchheim, Germany). A contrast-enhanced volume dataset was acquired (two tubes, 120 kV, 400 mAs/rot, collimation 64 x 0.6 mm). Datasets were evaluated concerning the presence of significant coronary stenoses and validated against invasive coronary angiography. RESULTS: In 44 patients with a heart rate > or =65 beats/min, 566 of 616 coronary segments were evaluable (92%), whereas in 56 patients with a heart rate <65 beats/min, 777 of 778 coronary segments were evaluable (100%, p < 0.001). On a per-patient basis, 93% of patients (> or =65 beats/min) and 100% of patients (<65 beats/min) were considered evaluable. By classifying unevaluable segments as positive for stenosis, per-patient sensitivity was 95% (19 of 20) for heart rates > or =65 beats/min and 100% (22 of 22) for heart rates <65 beats/min. Specificity was 87% (21 of 24) versus 76% (26 of 34), and overall diagnostic accuracy was 91% (40 of 44) versus 86% (48 of 56). None of these differences were statistically significant. Similarly, no difference in diagnostic accuracy was found in per-vessel and -segment analyses. CONCLUSIONS: In 100 patients studied without beta-blocker pre-medication, DSCT demonstrated slightly lower per-segment evaluability for high heart rates but no decrease in diagnostic accuracy for the detection of coronary artery stenoses.     

Comparison of multidetector 64-slice computed tomographic angiography to coronary angiography to assess the patency of coronary artery bypass grafts

This study prospectively evaluated the diagnostic accuracy of 64-slice computed tomographic angiography (CTA) in assessing the patency of coronary artery bypass grafts compared with invasive coronary angiography. In total 147 bypass grafts (100 venous grafts and 47 mammary artery grafts) were evaluated in 50 consecutive patients. Contrast-enhanced 64-slice CTA was performed and compared with invasive angiography. The computed tomographic angiographic scan protocol used 64- x 0.5-mm slice collimation and 0.33-second gantry rotation time during simultaneous electrocardiographic gating. Patients with a heart rate >65 beats/min received beta blockers. Overall 145 of 147 bypass grafts (98.6%) were detected by CTA; 2 nonvisualized grafts were occluded at the time of invasive angiography. Of the grafts visualized, 28 were totally occluded, 103 were patent, and 14 had significant stenoses that were confirmed by invasive angiography. Ninety-five percent (111 of 117) of patent grafts demonstrated good run-off distal to anastomoses but without an ability to accurately evaluate the presence of retrograde flow; 83% (97 of 117) of distal anastomoses were adequately evaluated, whereas the remaining 17% (20 of 117) were not well visualized due to vascular clips and/or calcification artifacts. Two grafts were not demonstrated by invasive angiography but were detected by CTA and found to be widely patent. In conclusion, multidetector 64-slice CTA is a valuable tool for direct visualization of coronary bypass grafts and assessment of their patency. Dysfunctional bypass grafts can be detected with high diagnostic accuracy.     

Diagnostic accuracy of 64-slice computed tomography for detecting angiographically significant coronary artery stenosis in an unselected consecutive patient population: comparison with conventional invasive angiography.

BACKGROUND: Multislice computed tomography (MSCT) is a promising noninvasive method of detecting coronary artery disease (CAD). However, most data have been obtained in selected series of patients. The purpose of the present study was to investigate the accuracy of 64-slice MSCT (64 MSCT) in daily practice, without any patient selection. METHODS AND RESULTS: Using 64-slice MSCT coronary angiography (CTA), 69 consecutive patients, 39 (57%) of whom had previously undergone stent implantation, were evaluated. The mean heart rate during scan was 72 beats/min, scan time 13.6 s and the amount of contrast media 72 mL. The mean time span between invasive coronary angiography (ICAG) and CTA was 6 days. Significant stenosis was defined as a diameter reduction of > 50%. Of 966 segments, 884 (92%) were assessable. Compared with ICAG, the sensitivity of CTA to diagnose significant stenosis was 90%, specificity 94%, positive predictive value (PPV) 89% and negative predictive value (NPV) 95%. With regard to 58 stented lesions, the sensitivity, specificity, PPV and NPV were 93%, 96%, 87% and 98%, respectively. On the patient-based analysis, the sensitivity, specificity, PPV and NPV of CTA to detect CAD were 98%, 86%, 98% and 86%, respectively. Eighty-two (8%) segments were not assessable because of irregular rhythm, calcification or tachycardia. CONCLUSION: Sixty-four-MSCT has a high accuracy for the detection of significant CAD in an unselected patient population and therefore can be considered as a valuable noninvasive technique.     

Comparison of sixty-four-slice multidetector computed tomographic coronary angiography to coronary angiography with intravascular ultrasound for the detection of transplant vasculopathy

Coronary allograft vasculopathy (CAV) is the most important limitation to long-term survival in adult heart transplant recipients and is difficult to detect without intravascular ultrasound (IVUS). We systematically evaluated the image quality of 64-slice multidetector computed tomographic (MDCT) coronary angiography in heart transplant recipients and tested the hypothesis that this modality is comparable to invasive coronary angiography with IVUS for the detection of CAV. Heart transplant recipients (n = 20) underwent invasive coronary angiography with IVUS and MDCT coronary angiography with a 64-slice scanner. Images were systematically analyzed for image quality and the presence of CAV. In addition, multidetector computed tomography and quantitative coronary angiography were used to measure lumen diameters at prespecified locations. Image quality analysis showed that, despite high mean heart rates (77 +/- 7 beats/min) and body mass index (29.5 +/- 5.3 kg/m(2)), 83% of coronary segments were graded as of excellent or good image quality. On average, 95 +/- 9% of the overall visualized length of the coronary arteries was imaged without motion artifacts, and the mean contrast-to-noise ratio was 11.3 +/- 4.6. Compared with IVUS, multidetector computed tomography had a sensitivity of 70%, specificity of 92%, positive predictive value of 89%, and negative predictive value of 77% for the detection of CAV. MDCT vessel diameter measurements correlated well with those obtained from quantitative coronary angiography (R(2) = 0.89). In conclusion, 64-slice multidetector computed tomography provides good to excellent image quality in heart transplant recipients and has moderate to excellent test characteristics for the detection of CAV. Further, MDCT measurements of lumen diameters correlated well with quantitative coronary angiography.     

Performance Evaluation of a Multi-Slice CT System with 16-Slice Detector and Increased Gantry Rotation Speed for Isotropic Submillimeter Imaging of the Heart

BACKGROUND: 4-slice CT scanners have shown limitations in clinical application for noninvasive coronary CT angiography (CTA). We evaluate advances in ECG-gated scanning of the heart and the coronary arteries with recently introduced 16-slice CT equipment (SOMATOM Sensation 16, Siemens, Forchheim, Germany). MATERIALS AND METHODS: The technical principles of ECG-gated cardiac scanning, scan parameters, and detector design of the new scanner are presented. ECG-gated scan and image reconstruction techniques and ECG-controlled dose modulation ("ECG pulsing") for a reduction of the patient dose are described, key parameters for image quality and simulation results presented, and phantom studies and initial patient experience discussed. The impact of reduced gantry rotation time (0.42 s) on temporal resolution and initial estimations of the patient dose are presented. RESULTS: Extensions of ECG-gated reconstruction algorithms used for 4-slice CT provide adequate image quality for up to 16 slices. For each detector collimation different slice widths are available for retrospective reconstruction with well-defined slice sensitivity profiles (SSPs). For coronary CTA the heart can be covered with 0.75 mm collimation within a 20-s breathhold. The best possible spatial resolution is 0.5 x 0.5 x 0.6 mm. For 0.42 s gantry rotation time, temporal resolution reaches its optimum (105 ms) at a heart rate of 81 bpm. Effective patient dose for coronary CTA is 4-5 mSv using ECG-pulsed acquisition. CONCLUSION: The clinical performance of coronary CTA by means of spatial resolution, temporal resolution and scan time is substantially improved with the evaluated 16-slice CT scanner. Also, display of smaller coronary segments and instent visualization are substantially improved.