Noninvasive coronary angiography using computed tomography

While noninvasive imaging of the coronary lumen remains challenging, great strides have been made with computed tomography. Two variations of computed tomography are used in the study of the coronary tree: multislice or multidetector computed tomography and electron-beam computed tomography. Both have high spatial and temporal resolutions as well as excellent signal-to-noise ratios, which allows major branches of the coronary tree to be depicted. Impaired image quality, due to dense calcifications and multiple image artifacts including coronary artery motion and breathing artifacts, limits the clinical utility of noninvasive coronary angiography. Early studies with electron-beam angiography demonstrated an overall sensitivity of 85% and specificity of 89% for the detection of obstructive coronary artery disease. With early diastolic imaging, the sensitivity and specificity increases to 92 and 93%, respectively (rather than 80% of the cardiac interbeat interval, where coronary motion is more pronounced). Multidetector computed tomography, with improved spatial resolution but decreased temporal resolution, produces results that vary depending on the equipment. Four-slice scanners have an average sensitivity of only 61%, and only 38% of patients have all four vessels or 15 segments available for analysis, due to both cardiac motion and calcification. Thinner slice collimation with eight and 16 slices have allowed for improved detection. Sensitivity and specificity improve to 80 and 86%, respectively. Furthermore, the number of assessable segments with eight-to 16-slice scanners improves significantly, compared with four-slice scanners (85 vs. 73%; p<0.001). If only assessable segments are included in analysis, sensitivity and specificity for multidetector-row computed tomography improves to nearly 90%. Compared with magnetic resonance imaging, with a reported accuracy of 72% in the only multicenter study, computed tomography has great promise to become the primary method of noninvasive coronary angiography.     

CT成像和平板运动试验与冠状动脉造影的对比研究

目的探讨64排螺旋CT冠状动脉成像与平板运动试验在冠心病诊治中联合应用的价值。方法以选择性冠状动脉造影结果为标准,对比分析64排螺旋CT冠状动脉成像和运动平板试验对114例疑诊冠心病和53例冠心病介入治疗患者诊断的敏感度、特异度、准确度、阳性预测值和阴性预测值。结果64排螺旋CT冠状动脉成像诊断冠心痛的敏感度为92．6％,特异度为98．8％,准确度98．4％,阳性预测值为82．5％,阴性预测值为99．5％。64排螺旋CT冠状动脉成像与平板运动试验两者联合应用诊断冠心病的敏感度为90．2％,特异度为99．5％,准确度为99．0％,阳性预测值为91．7％,阴性预测值为99．4％。结论64排螺旋CT冠状动脉成像与平板运动试验均是简便、易行及无创的冠心病诊断方法,两者联合应用可进一步提高诊断冠心病的准确度,并为冠心病介入疗效评价提供依据。     

双源CT自适应前瞻性心电触发序列扫描冠脉成像的临床应用

目的：评价第二代双源CT自适应前瞻性心电触发序列扫描冠脉成像的临床应用价值。方法：回顾性分析114例第二代双源CT自适应前瞻性心电触发序列扫描冠脉成像患者的图像,其中18例患者有2周内的冠脉造影对比。结果：本组114例患者检查过程中的平均心率为（63±8）次/min,图像平均质量评分为（1.65±0.59）分,优良图像占90.35%,可诊断图像占99.12%;96.53%（1 252/1 297）的冠脉节段达到可供诊断的图像质量;平均有效辐射剂量为（6.27±1.81） mSv;诊断冠心病38例,21例支架置入术后的48枚支架的通畅性得到评价,43枚支架通畅,4枚支架内再狭窄,1枚支架内闭塞;18例72支冠脉以冠脉造影为标准,双源CT冠脉成像诊断冠脉狭窄（按支）的敏感度、特异度、阳性预测值、阴性预测值分别为95.45%、96.00%、91.30%、97.96%。结论：第二代双源CT前瞻性心电触发序列扫描是一种安全、有效、低辐射、无创的冠脉成像技术,也是一种有效评价冠脉支架通畅性的方法。     

Eight-Row Multidetector Computed Tomography Coronary Angiography Evaluation of Significant Coronary Artery Disease in Patients with Severe Aortic Valve Stenosis

Background The aim of this study was to evaluate whether 8-row multidetector computed tomography coronary angiography (MDCT-CA) could replace invasive conventional coronary angiography (CCA) in patients with acquired severe aortic valve stenosis (AS). Coronary artery disease (CAD) diagnosis should be obtained with a noninvasive method in patients with AS undergoing valvular replacement. We evaluated the diagnostic accuracy of MDCT-CA in detecting high-grade (≥50%) stenoses in the main coronary arteries in patients with AS.Methods Twenty-three patients with acquired severe AS underwent both CCA and MDCT-CA. We calculated the total and volumetric calcium scores and evaluated the image quality of each coronary segment as assessable or nonassessable for stenosis. The images of the arteries were evaluated for the occurrence of artifacts and the presence of high-grade stenoses (≥50%) by visual estimation and comparison with that of CCA.Results Of the 322 segments screened 224 were assessable for stenosis. Heavy calcium load rendered 37 (38%) of the 98 coronary segments nonassessable.Compared to CCA, MDCT-CA had a sensitivity of 63%, a specificity of 96%, a positive predictive value of 52%, and a negative predictive value of 98% for ≥50% stenoses in the main coronary arteries.Conclusions Eight-row MDCT-CA revealed a low sensitivity in detecting significant coronary artery disease in patients with acquired severe AS. High calcium burden decreased visualization of the lumen and complicated most often a correct assessment. In this patient group, CCA should still remain the primary pre-surgical test to rule out coronary lesions requiring revascularization.     

Visual assessment of coronary artery stenosis with electrocardiographically-gated multislice computed tomography

BACKGROUND: With faster image acquisition times and thinner slice widths, multislice detector computed tomography (MSCT) allows visualization of human coronary arteries. Significantly improved image quality, with high resolution and new software for three-dimensional post-processing, has made noninvasive examination of the cavities within human body possible. OBJECTIVE: The aims of this study are to evaluate the diagnostic accuracy of ECG-gated MSCT for the detection of significant coronary artery stenosis and occlusions. METHODS: In 25 patients (19 male and 6 female aged 65+/-9 years) with suspected obstructive coronary artery disease, ECG-gated MSCT angiography was performed with an 8-slice MSCT scanner. Visual coronary arteries were simulated in three coronary arteries. Conventional coronary angiographies were performed in all patients. And coronary lesions in MSCT were estimated by two observers, who did not know the results of the coronary angiography. RESULTS: Current MSCT allows visual coronary artery with good image quality. The overall sensitivity for diagnosing significant coronary stenosis were 75.0%, the specificity was 95.6%. The positive and negative predictive values were 84.9 and 92.2%, respectively. The accuracy of MSCT for detecting coronary stenosis is the highest in the left main tranck and left anterior descending coronary artery, and lowest in the circumflex coronary artery. CONCLUSION: MSCT was feasible for the detection of coronary artery stenosis.     

320排动态容积CT冠状动脉成像与冠状动脉造影对比观察

目的比较320排动态容积CT（DVCT）冠状动脉成像和冠状动脉造影（CAG）对诊断冠状动脉狭窄的准确性。方法对56例患者的672个冠状动脉节段进行320排DVCT冠状动脉成像及CAG,并进行对比分析。结果可用于评估的672个冠状动脉节段中,CAG显示病变140个,320排DVCT显示其中132个,320排DVCT诊断冠状动脉病变的总体敏感度、特异度、阳性预测值和阴性预测值分别为92.3%、99.2%、96.9%和97.9%。冠状动脉管壁严重钙化是图像质量失实的主要原因。结论 320排DVCT在显示冠状动脉病变时,具有较高的敏感度和特异度,并且对于病变程度的评估也比较准确,对于预测及早期诊断冠心病,有重要的临床应用价值。     

40层螺旋CT对冠状动脉成像与冠状动脉造影的对比研究

目的 研究40层螺旋CT冠状动脉成像对冠状动脉疾病的诊断价值.方法 搜集79例可疑或已确诊为冠心病的患者进行40层螺旋CT扫描和常规冠状动脉造影,然后对2种检查方法的结果进行对比分析.结果 79例患者共有711个冠状动脉节段,其中675个（94.94%）可用于评价,结果显示40层螺旋CT诊断冠状动脉病变的敏感性为88.04%,特异性为91.08%,阳性预测值为77.47%,阴性预测值为93.56%.对冠状动脉〉50%狭窄的检出准确率为90.66%.结论 40层螺旋CT对冠心病的诊断及病变程度的评估具有较高的准确性、特异性和敏感性,可用于冠心病的初步筛选.     

64排CT冠状动脉成像诊断冠状动脉狭窄的临床价值

目的 评价64排CT冠状动脉成像(CTCA)技术诊断冠状动脉显著狭窄(≥50%管腔狭窄)的临床价值.方法 采用CTCA对61例临床疑诊冠心病患者进行检查,并于CTCA检查后2周内行选择性冠状动脉造影(SCA).结果 1例患者因冠状动脉严重钙化4支血管CTCA不可评估,其余60例患者240支冠状动脉血管CTCA均可良好显影,240支血管显著狭窄诊断的灵敏度、特异度、阳性预测值及阴性预测值分别为90.0%(72/80)、91.9%(147/160)、84.7%(72/85)、94.8%(147/155).结论 CTCA显示了较高的阴性预测值,可以作为排除冠状动脉显著病变的一种无创标准性检查.     

Cardiac CT and Stent Imaging: Update 2014

Percutaneous coronary intervention with stent implantation is a common technique for coronary revascularization. Despite the widespread use of drug-eluting stents in-stent restenosis (ISR) is still a major issue. Multidetector row computed tomography angiography of the coronary arteries is a well-established, noninvasive tool for the assessment of the coronary arteries. Stent imaging, however, is a challenging task with relevant rates of nondiagnostic scans due to motion and beam-hardening artifacts. Nevertheless, recent scanners provide excellent results for the exclusion of ISR with a negative predictive value of about 97 %. Further indications for CT imaging of coronary stents include the detection and visualization of stent-related complications such as stent fracture. During the last couple of years there have been some major advances in CT imaging of coronary stents relating to hardware and imaging protocols. This review describes recent advances in CT imaging of coronary stents and summarizes current results     

16层CT冠状动脉成像与选择性冠状动脉造影的对比研究

目的:探讨16层CT对冠状动脉粥样硬化病变的显示情况及临床价值。方法:39例患者进行16层CT冠状动脉造影检查(疑似冠心病者31例,PTCA术后8例)及选择性冠状动脉造影。分析16层CT对冠状动脉各节段的显示情况。以管腔直径减小>50%为标准,判定冠状动脉狭窄。分析16层CT诊断冠状动脉狭窄的敏感性、特异性及符合率,及对病变性质的显示情况。结果:16层CT对冠状动脉的总体显示率为94.8%(333/351)。评价冠状动脉病变的总体敏感性为82.2%,特异性为94.7%,符合率为86.0%。16层CT显示钙化及非钙化斑块混合存在致血管狭窄21处,高估3处;中间密度斑块致狭窄8处,高估3处;软斑块3处,无显著狭窄。16层CT能清晰显示支架位置、形态及远端血流,1例再狭窄,1例闭塞,余通畅,其结果与选择性冠状动脉造影一致。另外,16层CT显示冠状动脉起源变异2例,前降支冠状动脉瘤1例,室壁瘤1例,房间隔缺损1例。结论:16层CT冠状动脉成像是一种颇具潜力的无创性检查方法,能够较为准确、全面的评价冠状动脉病变。     

Applications and software techniques for integrated cardiac multimodality imaging

Several imaging technologies are available for diagnostic cardiac imaging, such as coronary computed tomography angiography (CTA), single photon emission computed tomography (SPECT) positron emission tomography (PET) and magnetic resonance imaging (MRI). Each of these techniques offers unique advantages, but also suffers from specific limitations. Software techniques are being developed to combine cardiac images from different modalities and generate composite multimodality images, allowing better diagnosis than that possible from images analyzed separately. Hybrid scanners (SPECT/CT and PET/CT) have also been proposed for integrated cardiac imaging. Physicians are presented with integrated fused images that contain complementary information from separate scans containing physiological and anatomical information. In this review, we present the latest approaches for integration of cardiac images from multiple modalities.     

多层螺旋CT在冠心病的临床应用价值及存在问题

目的在病例非选择性的基础上,将多层螺旋CT冠状动脉血管造影(CTA)与侵入性冠状动脉造影(ICA)相比,评估其准确性及敏感性,并分析其伪影产生的原因以及解决方法。方法对45名可疑冠心病患者在7~10d先后予以CTA及ICA检查,将二者相比。结果对45名患者从节段水平分析其敏感性、特异性、阳性预测值、阴性预测值为:85.0%,99.1%,93.1%,98.0%;患者水平分别为:84.8%,75.0%,90.3%,64.2%。结论CTA诊断准确性高,尤其表现在节段水平对于阴性预测值判断,从患者水平分析,其诊断价值下降,显示对于高度危险患者,常规行CTA检查,并不能从中获益。由于患者自身或扫描的原因会出现影响图像诊断的伪影,对这些伪影的成因及特点进行分析有助于提高CTA的成功率及避免假阳性的诊断。     

64排螺旋CT冠状动脉造影与传统冠状动脉造影的对照研究

目的探讨64排螺旋CT冠状动脉造影（computed tomography coronary angiography, CTCA）,,对冠状动脉疾病的诊断价值。方法56例确诊或怀疑为冠心病的患者均行64排螺旋CT冠状动脉成像和传统冠状动脉造影（conventional coro-nary angiography,CCA）检查,并以CCA的诊断结果作为金标准,采用美国心脏协会冠状动脉改良分段法,分析共825个冠状动脉节段CTCA图像质量及其对冠状动脉狭窄的显示情况,得出CTCA诊断有意义病变（冠状动脉狭窄≥50％）fl＇,J正确性,并分析影响CTCA图像质量的主要因素。结果798个冠状动脉节段图像可以满足诊断要求,12个节段中因运动伪影或15个节段管壁严重钙化无法对血管腔进行评估。64排螺旋CT冠状动脉成像诊断≥50％狭窄总的敏感性、特异性、阳性预测值、阴性预测值、准确性分别为88．1％、97．8％、89．9％、97．4％和96％。影响图像质量主要因素为快心率、严重钙化。结论64排螺旋CT冠状动脉成像图像质量高,对冠状动脉疾病的诊断十分准确,可作为一种简便易行、安全可靠的无创性筛查冠心病的有效方法。     

Anomalous origin of the three coronary arteries from the right aortic sinus Valsalva: Role of MDCT coronary angiography

Background Monocuspal origin of all three coronary arteries through separate ostia from the right aortic sinus (RCS) is a rare occurrence. To date, the use of multidetector computed tomography (MDCT) for imaging of congenitally abnormal coronary arteries has been discussed only in few individual case reports.Objective To describe the role of MDCT coronary angiography in the evaluation of two rare cases of monocuspal origin of all three coronary from RCS.Patients and methods We had a retrospective review of clinical information and imaging studies for two patients presented with chest pain. Both patients underwent conventional coronary angiography followed by noninvasive imaging with MDCT.Results Both patients had anomalous origin of the all three coronary arteries from the RCS. In one case the LAD took an intramural course in between the aorta and the right ventricular outflow tract (RVOT) while it passed anterior to the RVOT in the other patient. In the first patient, there was also associated coronary fistula to the right ventricle along with right coronary artery (RCA) and left anterior descending coronary artery (LAD) narrowing. Both the stenosed segments were successfully stented and were demonstrated to be patent in the subsequent MDCT.Conclusion Monocuspal origin of all three coronary artery from the RCS is a rare anomaly, can be reliably diagnosed by MDCT. CT angiogram is a convenient complementary tool for the coronary arteriography     

心脏电-机械耦联与双源CT冠状动脉成像最佳成像时间窗

冠状动脉CT成像已成为检测冠状动脉狭窄的一种有效的无创性手段,图像质量是影响其诊断准确性的重要因素。在整个心动周期内,冠状动脉所有节段都有相当大的变化,运动速度也随着心率加快而加快。目前的多排螺旋CT的时间分辨率仍不能满足获取冠状动脉在心动周期内任一瞬间清晰影像的需求。根据心脏电-机械耦联理论,选择不同心率和心律情况下相对低速的心电时相进行数据采集或图像重建,以减少心脏搏动产生的运动伪影。心脏电-机械耦联与冠状动脉成像最佳成像时间窗的选择对于不同心率、心律下冠状动脉CT成像有着重要意义,应用该理论可进一步提高心脏CT图像质量及诊断冠状动脉狭窄的准确性。     

Technical and Clinical Aspects of Coronary Computed Tomography Angiography

Coronary computed tomography angiography is an emerging imaging technique that has attracted much scientific attention over the past years. Improved scanner technology and dedicated protocols have made noninvasive coronary a reliable diagnostic test in patients with suspected coronary artery disease (CAD). Several technical steps such as the introduction of 64-slice scanners, multisegment reconstruction, and dual-source computed tomography have substantially improved temporal and spatial resolution. With these sophistications, coronary computed tomography angiography enables reliable exclusion of CAD in patients with low to intermediate pretest probability of having CAD or with inconsistent ischemia test results.     

Noninvasive assessment of coronary atherosclerosis by multidetector-row computed tomography

Assessment of atherosclerotic plaque burden may help to further stratify asymptomatic subjects with an intermediate cardiac event risk according to their conventional risk factors. Coronary calcium screening is a simple and effective method to noninvasively assess the atherosclerotic plaque burden. Standardized quantification of the coronary calcium mass will allow the results of ongoing prospective cohort studies to be used for any computed tomography (CT) scanner, electron-beam CT, as well as multidetector-row CT. Coronary multidetector-row CT angiography may have the potential to visualize vulnerable plaques that are prone to rupture and cause acute coronary symptoms. However, neither the reliability of detection nor the strategies for intervention of vulnerable plaques with multidetector-row CT have to date been proven.     

Noninvasive cardiac imaging in the evaluation of suspected acute coronary syndromes

Optimal management of patients presenting with chest pain to the emergency department is a major challenge, both in terms of a diagnostic dilemma and consumption of resources. The triage of such patients can be aided vastly by the appropriate use of noninvasive imaging. Noninvasive imaging modalities such as echocardiogram, radionuclide perfusion studies, positron emission tomography, cardiac magnetic resonance imaging and computed tomography have all been demonstrated to have favorable diagnostic and prognostic value, with an enhanced sensitivity to detect acute ischemia. A normal noninvasive evaluation in the appropriate clinical setting presents a strong argument against acute ischemia as an etiology of the chest pain. Randomized trials of both rest and stress imaging in the emergency department have confirmed a reduction in unnecessary hospitalizations and cost savings without compromising the safety of the patient. Cardiac magnetic resonance and computed tomography would provide an insight into subendocardial ischemia, the detection of which has previously been difficult, using single-photon emission tomography and echocardiography. In this review, novel hot-spot imaging modalities are discussed including infarct-avid imaging agents and ischemia-avid imaging agents, thus elucidating the pathophysiology of reperfusion-induced cell death. These agents represent work in evolution and are likely to be used routinely in the future as understanding of coronary syndromes and coronary artery disease becomes clearer.     

64层螺旋CT冠状动脉成像诊断冠状动脉狭窄价值

目的评价64层螺旋CT冠状动脉成像（CTA）诊断冠状动脉狭窄的准确性与可行性。方法 30例临床拟诊为冠心病的病人行64层螺旋CTA,以选择性冠状动脉DSA造影作为金标准,比较两种检查方法的结果。结果 120段冠状动脉在CTA图像上得到良好显示,达到分析要求。64层螺旋CT诊断冠状动脉狭窄（狭窄程度≥50%）的灵敏度、特异度、阳性预测值和阴性预测值分别为77.8%、85.3%、48.3%和95.6%。结论 64层螺旋CTA显示冠状动脉狭窄具有很高的阴性预测值,可作为一种无创检查技术对冠状动脉狭窄进行筛查。     

多层螺旋CT对冠状动脉桥血管的评价

目的 评价16层螺旋CT在冠状动脉搭桥术后随访中的价值。方法 8例冠状动脉搭桥术后患者行心电门控下16层螺旋CT冠状动脉成像。原始数据传至工作站，进行容积再现(VRT)、最大密度投影(MIP)、曲面重建(CPR)和仿真内窥镜(CTVE)等后处理，观察桥血管位置、管腔通畅情况。结果 在CT图像上，8例患者的12根桥血管均可用于评价，并且未发现明显再狭窄和闭塞。结论 16层螺旋CT可无创性对冠状动脉桥血管进行评价。