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-2011; to 16-2011;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 tomograpy 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.     

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     

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.     

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。     

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.     

多层螺旋CT冠状动脉成像与冠状动脉造影对照

背景：许多初步研究结果表明，16层螺旋CT对冠状动脉狭窄的显示具有较高的准确性。 目的：通过与冠状动脉造影对比评价多层螺旋CT诊断冠状动脉中、重度狭窄的准确性和局限性。 设计、时间及地点：金标准对照观察的临床诊断实验，于2005—06／2006—03在首都医科大学宣武医院心脏科完成。 对象：选择2005—06／2006—03首都医科大学宣武医院心内科收治的1个月内先后行64层螺旋CT和冠状动脉造影检查的临床诊断或可疑冠状动脉硬化性心脏病患者28例。 方法：采用国际上通用的目测直径法，对选择性冠状动脉造影或多层螺旋CT显示冠状动脉狭窄进行定量评价。分别对28例患者的280个节段进行分析。 主要观察指标：多层螺旋CT冠状动脉成像对冠状动脉狭窄的真阳性、真阴性、假阳性、假阴性以及灵敏度、特异度、准确度、阳性预测值、阴性预测值。 结果：纳入的28例患者全部进入结果分析。依节段计算多层螺旋CT的准确性，其灵敏度、特异度、阳性预测值和阴性预测值分别为46．5％，97．6％，86．8％和84-3％。若去除其中31个冠状动脉节段由于严重钙化而影响诊断的因素，则多层螺旋CT的诊断灵敏度、特异度、阳性预测值和阴性预测分别为     

Noninvasive angiography and assessment of left ventricular function using multislice computed tomography in patients with type 2 diabetes

OBJECTIVE: Early identification of coronary artery disease (CAD) in patients with diabetes is important because these patients are at increased risk for CAD and have worse outcome than nondiabetic patients after CAD is diagnosed. Recently, noninvasive coronary angiography and assessment of left ventricular function has been demonstrated with multislice computed tomography (MSCT). The purpose of the present study was to validate this approach in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: MSCT was performed in 30 patients with confirmed type 2 diabetes. From the MSCT images, coronary artery stenoses (> or =50% luminal narrowing) and left ventricular function (left ventricular ejection fraction, regional wall motion) were evaluated and compared with results of conventional angiography and two-dimensional echocardiography. RESULTS: Two hundred twenty of 256 coronary artery segments (86%) were interpretable with MSCT. In these segments, sensitivity and specificity for detection of coronary artery stenoses were 95%. Including the uninterpretable segments, sensitivity and specificity were 81 and 82%, respectively. Bland-Altman analysis in the comparison of left ventricular ejection fractions demonstrated a mean difference of -0.48 +/- 3.8% for MSCT and echocardiography, which was not significantly different from 0. Agreement between the two modalities for assessment of regional contractile function was excellent (91%, kappa statistic 0.81). CONCLUSIONS: Accurate noninvasive evaluation of both the coronary arteries and left ventricular function with MSCT is feasible in patients with type 2 diabetes. This noninvasive approach may allow optimal identification of high-risk patients.     

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。     

心率及心律因素对多层螺旋CT冠状动脉成像质量的影响及其改善措施

随着多层螺旋CT的快速发展,冠状动脉多层螺旋CT造影已成为一种无创、有效、准确的冠状动脉病变的检查手段.多层螺旋CT在心脏成像中的技术日益完善,随着其时间分辨率和空间分辨率的提高,其成像质量也得到明显的改善.心率及心律因素是影响图像质量的重要因素.本文对心率及心律因素对图像质量的影响程度、产生原因及一些改善措施方面的研究进行综述.     

Low-dose prospectively gated 256-slice coronary computed tomographic angiography

Since the introduction of 64-slice scanners, multidetector computed tomography (MDCT) has experienced a marked increase in adoption for the noninvasive assessment of coronary artery disease, although radiation dose concerns remain. The recent introduction of prospective coronary CT angiography (CCTA) has begun to address these concerns; however, its applicability with existing scanners remains limited to cohorts defined by heart rate, heart rate variability, and body mass index. This paper reviews prospective CCTA, the effect of heart rate and heart rate variability on image quality, and the physiologic basis for selection of optimal prospective imaging windows. We then discuss 256-slice technology and our first 4 months of clinical experience with 256-slice prospective CCTA. Our early clinical results indicate that high-quality, low-dose prospective coronary CTA may be applied to patients with higher heart rates, higher BMI, and with less sensitivity to heart rate variability using 256-slice MDCT.     

Responsible Use of Computed Tomography in the Evaluation of Coronary Artery Disease and Chest Pain

Many options are available to clinicians for the noninvasive evaluation of the cardiovascular system and patient concerns about chest discomfort. Cardiac computed tomography (CT) is a rapidly advancing field of noninvasive imaging. Computed tomography incorporates coronary artery calcium scoring, coronary angiography, ventricular functional analysis, and information about noncardiac thoracic anatomy. We searched the PubMed database and Google from inception to September 2009 for resources on the accuracy, risk, and predictive capacity of coronary artery calcium scoring and CT coronary angiography and have reviewed them herein. Cardiac CT provides diagnostic information comparable to echocardiography, nuclear myocardial perfusion imaging, positron emission tomography, and magnetic resonance imaging. A cardiac CT study can be completed in minutes. In patients with a nondiagnostic stress test result, cardiac CT can preclude the need for invasive angiography. Prognostic information portends excellent outcomes in patients with normal study results. Use of cardiac CT can reduce health care costs and length of emergency department stays for patients with chest pain. Cardiac CT examination provides clinically relevant information at a radiation dose similar to well-established technologies, such as nuclear myocardial perfusion imaging. Advances in technique can reduce radiation dose by 90%. With appropriate patient selection, cardiac CT can accurately diagnose heart disease, markedly decrease health care costs, and reliably predict clinical outcomes.CAC = coronary artery calcium; CAD = coronary artery disease; CT = computed tomography; CTA = coronary computed tomographic angiography; EBCT = electron beam CT; ED = emergency department; ICA = invasive coronary angiography; MDCT = multidetector helical CT; MI = myocardial infarction; MPI = myocardial perfusion imaging; NPV = negative predictive value; PPV = positive predictive valueCardiac computed tomography (CT) is a rapidly evolving technology for the noninvasive evaluation of the cardiovascular system. Numerous potential roles for cardiac CT have been developed recently, such as investigating anomalous coronary arteries, evaluating for pulmonary vein stenoses, and preparing for repeated coronary artery bypass grafting. However, the indication of most interest to the public and physicians is evaluating patients for native vessel coronary artery disease (CAD) using coronary artery calcium (CAC) scoring and coronary computed tomographic angiography (CTA).We searched the PubMed database and Google, from inception to September 2009, for keywords coronary artery calcium, coronary CT angiography, and radiation risk to identify information sources of interest. We also searched references in other review articles. From Google, we selected publications from trusted sources, such as the Food and Drug Administration and the National Academy of Sciences. From PubMed, we selected articles about test performance characteristics based on the quality of their methods, preferentially using randomized controlled trial data. We selected articles about clinical outcomes from randomized trials when available and from large cohorts as secondary sources. The purpose of this review is to summarize the recent data regarding accuracy, sensitivity, and specificity of CTA and the responsible use of cardiac CT.     

Low-dose prospectively gated 256-slice coronary computed tomographic angiography

Since the introduction of 64-slice scanners, multidetector computed tomography (MDCT) has experienced a marked increase in adoption for the noninvasive assessment of coronary artery disease, although radiation dose concerns remain. The recent introduction of prospective coronary CT angiography (CCTA) has begun to address these concerns; however, its applicability with existing scanners remains limited to cohorts defined by heart rate, heart rate variability, and body mass index. This paper reviews prospective CCTA, the effect of heart rate and heart rate variability on image quality, and the physiologic basis for selection of optimal prospective imaging windows. We then discuss 256-slice technology and our first 4 months of clinical experience with 256-slice prospective CCTA. Our early clinical results indicate that high-quality, low-dose prospective coronary CTA may be applied to patients with higher heart rates, higher BMI, and with less sensitivity to heart rate variability using 256-slice MDCT.     

320排CT冠状动脉成像与冠状动脉造影的影像对比研究

目的以选择性冠状动脉造影（SCA）为＂金标准＂评价320排CT冠状动脉成像技术对诊断冠状动脉狭窄的准确性。方法选择冠心病诊断明确或可疑冠心病患者共86例（男49例,女37例）。所有患者的心律均为窦性心律,心率≥75次/min的患者口服倍他乐克控制心率;均同期行320排器官动态容积CT（DVCT）与SCA,将320排DVCT与SCA的结果进行对照研究,直径≥1.5mm的冠状动脉节段纳入结果分析,冠状动脉狭窄定义为≥50%的狭窄,分析320排DVCT对冠状动脉不同节段、不同分支狭窄判断的准确性;并根据有无伪影和是否符合进一步狭窄评价的要求将冠状动脉图像质量分为四个等级（Ⅰ～Ⅳ级）。结果 320排DVCT显示的1032个冠状动脉节段均符合影像学评价要求（Ⅰ～Ⅲ级）;计算320排DVCT评价冠状动脉有无狭窄的总体敏感度、特异度、阳性预测值和阴性预测值分别为92.7%、96.1%、86.4%和98.0%,准确度为94.7%。结论 320排DVCT能清楚显示冠状动脉各分支节段,较为准确的诊断冠状动脉狭窄程度,亦可作为无创性诊断冠状动脉疾病的有力工具。     

Uncommon double fistula between sinus node arteries and right atrium in a patient with atypical chest pain

The main coronary artery variants and anomalies are completely asymptomatic and are discovered incidentally or as they rise symptoms. Multidetector computed tomography coronary angiography represents an excellent technique for noninvasive assessment of the coronary tree mainly because of the multiplanar imaging modalities of computed tomography. Thin collimation permits to depict thin vessels such as the sinus node artery, as reported in this case. In this brief report, we describe a case of a rare anomaly of termination the coronaries, a double fistula between the sinus node artery, and the right atrium in a patient with atypical chest pain.     

Recent developments in wide-detector cardiac computed tomography

Multidetector computed tomography (MDCT) using 64 detectors is widely used for cardiac imaging in the clinical setting. Despite promising results, 64-slice MDCT has important limitations for cardiac applications related to detector coverage, which leads to longer scan times, image artifacts, increased radiation and the need for higher contrast doses. The advent of wide or full cardiac coverage with 256- or 320-slice MDCT provides important advantages that can potentially improve the status of these limitations and expand the utility of cardiac MDCT imaging beyond coronary imaging. Additionally, the combination of wide-detectors and multi-energy acquisitions offer interesting possibilities of improved coverage and temporal resolution that may improve plaque characterization as well as viability and perfusion imaging. In this review we will discuss the current status of wide-detector MDCT scanners and their advantages for clinical coronary and ventricular imaging. We will also review examples of wide detector coronary angiography imaging and discuss emerging complementary non-coronary applications that have been enabled by wide-detector MDCT imaging.     

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。     

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。     

Recent developments in wide-detector cardiac computed tomography

Multidetector computed tomography (MDCT) using 64 detectors is widely used for cardiac imaging in the clinical setting. Despite promising results, 64-slice MDCT has important limitations for cardiac applications related to detector coverage, which leads to longer scan times, image artifacts, increased radiation and the need for higher contrast doses. The advent of wide or full cardiac coverage with 256- or 320-slice MDCT provides important advantages that can potentially improve the status of these limitations and expand the utility of cardiac MDCT imaging beyond coronary imaging. Additionally, the combination of wide-detectors and multi-energy acquisitions offer interesting possibilities of improved coverage and temporal resolution that may improve plaque characterization as well as viability and perfusion imaging. In this review we will discuss the current status of wide-detector MDCT scanners and their advantages for clinical coronary and ventricular imaging. We will also review examples of wide detector coronary angiography imaging and discuss emerging complementary non-coronary applications that have been enabled by wide-detector MDCT imaging.     

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.     

MRI检测活性心肌及其与冠状动脉造影、SPECT和PET对比研究

目的：分析MRI对冠心病患者心肌活性的诊断价值并与冠状动脉造影、SPECT和PET结果对比。方法：应用MRI对21例临床符合冠心病的患者进行检查，并将结果与冠状动脉造影、SPECT和PET检查结果对照。结果：MRI静息心肌灌注扫描检出的缺血节段比狭窄冠状动脉的供血节段少但无统计学差异（Z=-1.732，P=0．083）；比SPECT心肌灌注扫描检出的缺血节段多且有统计学差异（Z=-3．691，P=0．000）。SPECT心肌灌注扫描检出的缺血节段比狭窄冠状动脉的供血节段少且有统计学差异（Z=-3．029，P=0．002）。以正电子发射断层显像（PET）结果为标准，MR延迟扫描检测活性心肌的灵敏度为97．6％，特异度为98．4％，总符合率为98．2%，Kappa值为0．953。MR延迟扫描检出的活性心肌比PET检出的少但无统计学差异（Z=-0．209，P=0．835）。结论：MR心脏检查清晰显示心肌梗死的位置、程度和附壁血栓情况，并可对左室室壁运动进行直观显示。常规SPECT心肌灌注显像由于空间分辨率低明显低估心肌缺血范围。心肌PET显像空间分辨率低，无法显示心肌梗死的透壁程度，且不能直观显示室壁运动情况。