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。     

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。     

心率波动对冠状动脉运动及64层螺旋CT冠状动脉成像质量的影响

目的探讨心率波动对冠状动脉运动及64层螺旋CT冠状动脉成像质量的影响。方法选取本院;临床中请多层螺旋CT冠状动脉成像（MSCTCA）且同意参加试验者34例为试验组,根据两次扫描心率变化分为三组,A组：≤5次／minBMP,B组：6～10次／minBMP,C组：〉10次／minBMP。分别测量心脏收缩末期和舒张末期右冠状动脉和左前降支间的距离,计算两次扫描的距离变化差。回顾性收集同期64SCTCA资料完整者137例为临床组,根据心率波动程度分成三组：Ⅰ组：0～2次／minBMP,Ⅱ组：3～6次／minBMP,Ⅲ组：〉7次／minBMP。按5分法评价不同心率波动情况下的图像质量。结果试验组两次扫描右冠状动脉与左前降支的间距差以舒展期变化较大,同收缩期比较差异有统计学意义（P〈0．05）;心率变化越大,距离的变化值也越大（P〈0．05）。临床组137例患者共有83．2％冠状动脉图像质量可满足诊断要求。不同心率波动组间冠状动脉图像质量有显著差异,心率变化越小图像质量越好（P〈0．05）。结论心率波动时数据匹配错误是导致图像质量降低的根本因素,稳定心率有助于提高图像质量。     

64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术的临床应用

目的探讨64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术在冠心病诊断的临床应用。方法对74例临床拟诊冠心病的患者进行64层螺旋CT冠状动脉成像检查。重建冠状动脉图像,显示冠状动脉分支血管,测量冠状动脉狭窄程度、长度;对检出的86段粥样硬化斑块采用彩色编码技术进行标记和测算。结果64层螺旋CT冠状动脉成像受心率影响较大,在控制心率≤70次／min时,冠状动脉1-13段血管97．4％（823／845）图像质量为1级,粥样硬化斑块及冠状动脉狭窄清晰显示。彩色编码技术检出不稳定斑块27块,其中19个斑块导致冠状动脉26％～50％狭窄,5个斑块导致冠状动脉51％-75％狭窄。结论64层螺旋CT冠状动脉成像及冠状动脉彩色编码技术可以非创伤性地显示冠状动脉狭窄程度及导致冠状动脉狭窄的斑块中各成分形态、分布及比例,可作为对冠心病患者进行筛查及初步预后评估的首选方法。     

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。     

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.     

心电前门控冠状动脉CT成像在快心率患者中的应用对策

目的探讨通过增加padding的方法,评估64层螺旋CT前门控冠状动脉CT成像在相对快心率患者的应用价值。方法选择心率>65/min患者30例(病例组),通过增加padding至180ms,重建40%⁸0%相位,评价冠状动脉图像质量,分析有效辐射剂量,并与30例(对照组)用回顾性心电门控螺旋CT冠状动脉重建方法辐射剂量进行对比。结果 98.3%的冠状动脉血管能够满足诊断要求,其中通过增加padding重建收缩期40%80%相位,评价冠状动脉图像质量,分析有效辐射剂量,并与30例(对照组)用回顾性心电门控螺旋CT冠状动脉重建方法辐射剂量进行对比。结果 98.3%的冠状动脉血管能够满足诊断要求,其中通过增加padding重建收缩期40%⁴5%相位窗,28.3%的冠状动脉血管图像质量改善,其中7例患者(23.3%)的12支血管(10.0%)图像质量由不能诊断改善为可以用于诊断;病例组平均辐射剂量明显低于对照组(3.5mSv vs 10.1mSv,P<0.01)。结论前门控轴扫增加padding用于相对快心率患者,可改善图像质量,避免用辐射剂量更高的回顾性心电门控螺旋CT扫描方法。     

优化重组技术在冠心病患者心率过快和心率波动中的诊断价值评估

目的：探讨优化重组技术在冠心病患者心率过快和心率波动中的诊断价值。方法选取196例确诊为冠心病的患者,据心率程度及波动范围分为四组,均行64层螺旋CT检查,以优化重组技术评估各组各支冠脉可评价率。结果四组自动重组后各支血管图像质量比较差异均有统计学意义（ P＜0.01）,A组优于其他三组（ P＜0.01）;再次优化重组后各支血管图像质量比较,左回旋支及右冠状动脉差异有统计学意义（ P＜0.01）;自动重组和再次优化重组后,B、C、D组各支可评价率比较差异均有统计学意义（ P＜0.05或P＜0.01）。结论64层螺旋CT优化重组技术可有效提高影像图像可评价率,但仍存在一定的局限和不足,检查前有效控制心率及心率波动可提高可评价率和诊断率。     

16层螺旋CT冠状动脉造影重建的最佳时相选择

目的探讨16层螺旋CT冠状动脉造影的最佳重建时相。方法对136例临床诊断或拟诊冠心病的患者行16层螺旋CT冠状动脉造影,选取增强扫描R-R心动周期0%～100%的10组图像(间隔10%),评价不同重建时相冠状动脉各主要分支的图像质量等级及可评价冠状动脉数,选择显示最清晰的一组记录时相。对最佳时相的薄层图像进行最大密度投影、二维曲面重建、多平面重建和容积再现重建。结果每位患者的3条冠状动脉分支(左前降支、左回旋支、右冠状动脉)分别用于图像质量分析。各时相之间显示可评价冠状动脉血管数有显著性差异(P<0.05)。重建相位窗40%、50%、70%和80%与其它相位窗之间在显示高质量冠状动脉数量上有显著性差异(P<0.05)。左前降支、左旋支和右冠状动脉在80%和70%相位窗上显示最佳,其次是40%和50%相位窗。结论选择最佳时相进行图像重建可以最大限度减轻心脏运动伪影,提高图像质量。     

64层螺旋CT冠状动脉支架成像效果的影响因素

目的 探讨64层螺旋CT冠状动脉支架成像效果的影响因素.方法选取冠状动脉药物涂层金属支架植入术后行64层螺旋CT检查的病例116例,对支架部位图像质量采取半定量评价,分析支架直径、支架长度、支架材质、支架个数和钙化情况对支架部位CT图像质量的影响.结果 64层螺旋CT检出有意义支架内再狭窄的敏感度、特异度、阳性预测值、阴性预测值分别为85.7%、90.2%、60.0%、97.4%.直径2.75 mm以上支架的CT图像质量优于直径2.75 mm及以下的支架(P<0.001),非钙化病变的支架术后CT图像质量优于钙化病变(P<0.05).支架长度、支架材质和是否多支架对支架部位CT图像质量无影响.结论 64层螺旋CT能胜任冠状动脉支架术后复查.直径2.75 mm以上支架和非钙化病变的支架病例更适合用64层螺旋CT进行复查.     

CT Coronary Angiography: 256-Slice and 320-Detector Row Scanners

Multidetector computed tomography (MDCT) has rapidly evolved from 4-detector row systems in 1998 to 256-slice and 320-detector row CT systems. With smaller detector element size and faster gantry rotation speed, spatial and temporal resolution of the 64-detector MDCT scanners have made coronary artery imaging a reliable clinical test. Wide-area coverage MDCT, such as the 256-slice and 320-detector row MDCT scanners, has enabled volumetric imaging of the entire heart free of stair-step artifacts at a single time point within one cardiac cycle. It is hoped that these improvements will be realized with greater diagnostic accuracy of CT coronary angiography. Such scanners hold promise in performing a rapid high quality “triple rule-out” test without high contrast load, improved myocardial perfusion imaging, and even four-dimensional CT subtraction angiography. These emerging technical advances and novel applications will continue to change the way we study coronary artery disease beyond detecting luminal stenosis.     

Diagnostic accuracy of noninvasive coronary angiography with 320-detector row computed tomography

We sought to evaluate the diagnostic accuracy of noninvasive coronary angiography using 320-detector row computed tomography, which provides 16-cm craniocaudal coverage in 350 ms and can image the entire coronary tree in a single heartbeat, representing a significant advance from previous-generation scanners. We evaluated 63 consecutive patients who underwent 320-detector row computed tomography and invasive coronary angiography for the investigation of suspected coronary artery disease. Patients with known coronary artery disease were excluded. Computed tomographic (CT) studies were assessed by 2 independent observers blinded to results of invasive coronary angiography. A single observer unaware of CT results assessed invasive coronary angiographic images quantitatively. All available coronary segments were included in the analysis, regardless of size or image quality. Lesions with >50% diameter stenoses were considered significant. Mean heart rate was 63 ± 7 beats/min, with 6 patients (10%) in atrial fibrillation during image acquisition. Thirty-three patients (52%) and 70 of 973 segments (7%) had significant coronary stenoses on invasive coronary angiogram. Seventeen segments (2%) were nondiagnostic on computed tomogram and were assumed to contain significant stenoses on an "intention-to-diagnose" analysis. Sensitivity, specificity, and positive and negative predictive values of computed tomography for detecting significant stenoses were 94%, 87%, 88%, and 93%, respectively, by patient (n = 63), 89%, 95%, 82%, and 97%, respectively, by artery (n = 260), and 87%, 97%, 73%, and 99%, respectively, by segment (n = 973). In conclusion, noninvasive 320-detector row CT coronary angiography provides high diagnostic accuracy across all coronary segments, regardless of size, cardiac rhythm, or image quality.     

Dual-Source Computed Tomographic Coronary Angiography: Image Quality and Stenosis Diagnosis in Patients with High Heart Rates

We sought to evaluate prospectively the effects of heart rate and heart-rate variability on dual-source computed tomographic coronary image quality in patients whose heart rates were high, and to determine retrospectively the accuracy of dual-source computed tomographic diagnosis of coronary artery stenosis in the same patients.We compared image quality and diagnostic accuracy in 40 patients whose heart rates exceeded 70 beats/min with the same data in 40 patients whose heart rates were 70 beats/min or slower. In both groups, we analyzed 1,133 coronary arterial segments. Five hundred forty-five segments (97.7%) in low-heart-rate patients and 539 segments (93.7%) in high-heart-rate patients were of diagnostic image quality. We considered P < 0.05 to be statistically significant. No statistically significant differences between the groups were found in diagnostic-image quality scores of total segments or of any coronary artery, nor were any significant differences found between the groups in the accurate diagnosis of angiographically significant stenosis.Calcification was the chief factor that affected diagnostic accuracy. In high-heart-rate patients, heart-rate variability was significantly related to the diagnostic image quality of all segments (P = 0.001) and of the left circumflex coronary artery (P = 0.016). Heart-rate variability of more than 5 beats/min most strongly contributed to an inability to evaluate segments in both groups. When heart rates rose, the optimal reconstruction window shifted from diastole to systole.The image quality of dual-source computed tomographic coronary angiography at high heart rates enables sufficient diagnosis of stenosis, although variability of heart rates significantly deteriorates image quality.Key words: Artifacts, coronary angiography/methods, coronary stenosis/diagnosis/radiography, diastole/physiology, heart rate/physiology, image processing, computer-assisted, prospective studies, radiographic image interpretation, computer-assisted, sensitivity and specificity, systole/physiology, technology assessment, biomedical, tomography, spiral computed/instrumentation/methods/standardsDuring the past few years, noninvasive coronary angiography upon multidetector-row computed tomography (MDCT) has rapidly progressed and has shown promise with regard to the detection and quantification of coronary artery stenosis.^1–4 However, despite the increase in temporal resolution from 16- to 64-detector-row computed tomography (CT), coronary CT angiography remains sensitive to motion artifacts, which occur especially at higher heart rates.^2,5–7 Results of a study³ of 64-detector-row CT coronary angiography showed a nonsignificant tendency toward lower image quality at higher mean heart rates, and a significant negative relation between image quality and heart-rate variability. In order to reduce motion artifacts, it has been proposed that patients be administered oral β-blocker medication for heart-rate control, even when 64-detector-row CT is to be used.^8–11 In most studies that have involved 16- or 64-detector-row CT, the target for scanning has been maintained at heart rates slower than 70 or even 60 beats/min, so that good-quality images of coronary arteries could be obtained. The requirement to premedicate patients with β-blocker drugs in order to achieve a sufficiently low heart rate for scanning has been considered a major limitation surrounding the clinical use of MDCT coronary angiography.Dual-source CT (DSCT) coronary angiography incorporates 2 X-ray tubes and 2 detectors that are mounted onto a rotating gantry, with an angular offset of 90°.¹² The DSCT system affords a high temporal resolution of 83 ms in monosegment reconstruction mode. In contrast with single-source CT systems that rely on multisegment reconstruction techniques, temporal resolution upon DSCT is independent of heart rate. Initial studies have shown that DSCT enables the study of coronary arteries with excellent diagnostic quality in all patients, independent of heart rate—thus obviating the need to premedicate patients with β-blockers.^12–15 We believed that the effects of heart rate and heart-rate variability on image quality, diagnostic accuracy, and optimal reconstruction windows merited further evaluation in patients whose heart rates exceeded 70 beats/min.The aim of this study was to evaluate prospectively the effect of heart rate and heart-rate variability on DSCT image quality in patients who had high heart rates, and to determine retrospectively the accuracy of DSCT in the diagnosis of coronary artery stenosis, using invasive coronary angiography as the reference standard.     

起搏器置入患者的640层CT冠状动脉成像初步研究

目的 探讨心脏起搏器置入患者应用640层动态容积CT行冠状动脉(冠脉)成像的可行性和图像质量.方法 16例体内置入心脏起搏器的连续病例应用640层容积CT行前瞻性心电门控冠脉成像.由两位有经验的放射诊断医师双盲评价冠脉15个节段的图像质量以及起搏器电极的金属伪影对冠脉节段的影响,同时记录扫描过程中的心电资料,进行统计分析.结果 起搏器置入患者640层CT冠脉造影图像质量优良率达到99.07%,1级占到83.64%,低心率组与高心率组、正常起搏心律组与心律失常组的冠脉图像质量评分以及起搏器电极的金属伪影对冠脉节段的影响差异均无统计学意义,P＞0.05.起搏器电极的金属伪影可降低右冠脉近段(S1)、中段(S2)、远段(S3)及后降支(S4)、左前降支远段(S8)的图像质量,其中以右冠脉近段(S1)、中段(S2)多见.调整重建期相后,冠脉节段的图像质量明显改善,重建期相调整前后的差异有统计学意义(x2=151.818,P＜0.01).结论 心脏起搏器置入患者行前瞻性心电门控640层容积CT冠脉成像能提供优秀的图像质量,起搏器电极金属伪影可降低部分冠脉节段的图像质量,改变重建期相能显著改善伪影.

Abstract：

Objective To investigate the feasibility and image quality of coronary artery angiography with 640-slice CT system in the pacemaker patients. Methods ECG-triggered 640-slice CT coronary angiography was performed in 16 pacemaker patients. Image quality of the fifteen coronary segments and metal-related artifact originating from pacemaker were assessed by two experienced radiologists in consensus.Image quality was assessed using a 4-point grading scale. ECG trigger information was recorded. Results The rate of available diagnostic images was 99. 07% ( Grade 1 in 83.64%, Grade 2 in 15.42%, Grade 3 in 0. 47% and Grade 4 in 0. 47% of patients, respectively). Image quality and the effect of streak artifact were similar between the high heart rate group and low heart rate group ( P ＞ 0. 05 ) and between normal pacing group and arrhythmia group ( P ＞ 0. 05 ). In coronary MSCT angiography, streak artifact of the pacemaker can render segments of the coronary artery uninterpretable, especially on S1, S2, S3, S4 and S8 segments of the coronary artery. Small shifts in the reconstruction window resulted in significance reduction of streak artifact ( x2 = 151. 818, P ＜ 0. 01 ). Conclusions 640-slice gated CT coronary angiography could provide excellent image quality for patients with pacemaker. The streak artifact induced by pacemaker on some segments of the coronary artery could be improved by small shifts in the reconstruction window.     

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.     

Noninvasive visualization of coronary artery bypass grafts using 16-detector row computed tomography

OBJECTIVES: The aim of this study was to evaluate the diagnostic accuracy of a 16-detector row computed tomography (CT) scanner for the assessment of coronary artery bypass grafts. BACKGROUND: A new generation of multislice spiral CT scanners, equipped with more and thinner detector rows, allows for reliable noninvasive detection of obstructive coronary artery disease. METHODS: The study included 51 consecutive patients. Three patients had to be excluded from the study due to arrhythmias or fast heart rates despite beta-blockade. A total of 48 patients with 131 coronary artery bypass grafts (internal mammary artery, n = 40; venous grafts, n = 91) were examined by computed tomography angiography (CTA) and by invasive coronary angiography (ICA) using a 16-detector row CT scanner. For cardiac protocols, only the 12 inner detector rings are applied. All CT examinations were performed with retrospective electrocardiogram gating at a mean heart rate of 64 +/- 5 beats/min; 120 ml of Xenetix 300 (Guerbert GmbH, Sulzbach, Germany) were continuously injected. The bypass graft patency and the presence of stenoses as well as the proximal and distal anastomoses were evaluated by two experienced readers. RESULTS: All bypass grafts and 74% of the distal bypass anastomoses could be visualized by CTA; 21 bypass graft occlusions and 1 significant stenosis were detected by CTA and confirmed by ICA. Five false positive and one false negative finding resulted in a sensitivity of 96%, a specificity of 95%, a positive predictive value of 81%, and a negative predictive value of 99%. CONCLUSIONS: Sixteen-detector row CT scanner technology allows for the reliable visualization of coronary bypass grafts. Dysfunctional bypass grafts can be detected with high diagnostic accuracy. This technology can be used as a noninvasive test for patients with suspected graft dysfunction.     

螺旋CT冠状动脉造影心率控制方法探讨

目的 探讨行多层螺旋CT冠状动脉造影时简单、有效的心率控制方法.方法 对2005年10月至2006年5月间在我科进行螺旋CT冠状动脉造影498例患者根据患者基础心率情况分为三组,采取不同的方法控制其心率.结果 针对患者基础心率采取不同的心率控制方法,可以到达满意的结果,且具有操作简单、无创、痛苦少、易于接受等特点.结论 尽管控制心率的方法不同,只要选择受检对象适当,均可达到理想的要求心率.从而提高影像质量.     

两种方法控制64排螺旋CT冠状动脉成像中心率的比较

目的: 通过两组病例的对比研究,探讨控制患者检查前的心率和效果。方法: 基础心率大于70次/min的患者654例,分为药物干预组352例和心理干预组302例,进行不同的心率干预措施后行64排螺旋CT冠状动脉成像,将两组患者的心率控制效果,冠状动脉图像质量及图像后处理的时间进行比较。结果: 经过口服倍他乐克减慢和稳定心率后, 340例（96.6%）心率降至70次/min以下,12例（3.4%）口服倍他乐克者未降至目标心率。352例患者中有347例（98.8%）的整体图像能满足诊断要求。心理干预组127例（42.0%）经过给予心理护理后心率降至70次/min 以下,154例（58.0%）未降至目标心率。302例患者中266例（88%）能满足诊断要求。控制组图像后处理的平均时间为（12±5）min,对照组图像后处理的平均时间为（18±6）min。结论: 倍他乐克可降低心率明显提高冠状动脉CTA的成像质量,药物控制心率优于心理护理。