Intravenous coronary angiography using electron beam computed tomography

Intravenous coronary angiography with electron beam computed tomography (EBCT) allows for the noninvasive visualisation of coronary arteries. With dedicated computer hardware and software, three-dimensional renderings of the coronary arteries, veins, and other cardiac structures can be constructed from the individual transaxial tomograms. Interest in this technique is growing, and recently a number of clinical studies have been published comparing EBCT coronary angiography with conventional cine-coronary angiography. In this article, image acquisition, postprocessing techniques, and the results of recently published clinical studies are discussed. EBCT coronary angiography is a promising imaging technique of coronary arteries. Currently, it is a reasonably robust technique for the visualization and assessment of the left main and left anterior descending coronary artery. However, at the moment a relatively high proportion of the right and circumflex coronary angiograms are noninterpretable. Improvements in image acquisition and postprocessing techniques are expected to improve visualization and diagnostic accuracy of the technique.     

Contrast enhanced electron beam computed tomography to analyse the coronary arteries in patients after acute myocardial infarction

OBJECTIVE—To evaluate the accuracy of contrast enhanced electron beam computed tomography (EBCT) after acute myocardial infarction in determining patency of the infarct related artery and detecting high grade stenoses and occlusions in the coronary vessels.
DESIGN—Case study using blinded comparison with invasive coronary angiography.
PATIENTS—36 patients (mean age 53 years) 4-70 days after acute myocardial infarction.
INTERVENTIONS—The patients were studied by EBCT and invasive coronary angiography. For EBCT, 50 axial images of the heart (3 mm slice thickness) were acquired. They were triggered by the ECG during breath holding, after intravenous injection of contrast agent. The original images, surface reconstructions, and maximum intensity projections were evaluated for the presence of high grade stenoses and occlusions of the coronary arteries.
MAIN OUTCOME MEASURES—EBCT results were compared with invasive coronary angiography.
RESULTS—Of a total of 144 coronary arteries (left main, left anterior descending, left circumflex, and right coronary artery in 36 patients), 29 (20%) were unevaluable by EBCT. In the remaining arteries, 33 of 36 high grade lesions were correctly detected (92% sensitivity). Specificity was also 92% (73/79). Patency of the infarct related artery was correctly detected in 15 of 16 cases (94%). Five of the 14 occluded infarct related arteries (35%) were mistaken as stenotic but patent, and six could not be assessed.
CONCLUSIONS—EBCT is very accurate in detecting significant coronary artery lesions in patients after acute myocardial infarction, but differentiation between occluded and patent infarct related arteries is currently unreliable.


Keywords: electron beam CT; coronary angiography; myocardial infarction; computed tomography     

Magnetic resonance imaging of the coronary arteries: clinical results from three dimensional evaluation of a respiratory gated technique

BACKGROUND—Magnetic resonance coronary angiography is challenging because of the motion of the vessels during cardiac contraction and respiration. Additional challenges are the small calibre of the arteries and their complex three dimensional course. Respiratory gating, turboflash acquisition, and volume rendering techniques may meet the necessary requirements for appropriate visualisation.
OBJECTIVE—To determine the diagnostic accuracy of respiratory gated magnetic resonance imaging (MRI) for the detection of significant coronary artery stenoses evaluated with three dimensional postprocessing software.
METHODS—32 patients referred for elective coronary angiography were studied with a retrospective respiratory gated three dimensional gradient echo MRI technique. Resolution was 1.9 × 1.25 × 2 mm. After manual segmentation three dimensional evaluation was performed with a volume rendering technique.
RESULTS—Overall 74% (range 50% to 90%) of the proximal and mid coronary artery segments were visualised with an image quality suitable for further analysis. Sensitivity and specificity for the detection of significant stenoses were 50% and 91%, respectively.
CONCLUSIONS—Volume rendering of respiratory gated MRI techniques allows adequate visualisation of the coronary arteries in patients with a regular breathing pattern. Significant lesions in the major coronary artery branches can be identified with a moderate sensitivity and a high specificity.


Keywords: magnetic resonance imaging; coronary artery disease; coronary angiography; computer assisted image processing     

Congenital coronary anomalies in adults: comparison of anatomic course visualization by catheter angiography and electron beam CT.

The objective of this study was to compare the anatomic course of anomalous coronary arteries by axial and three-dimensional volume-rendered electron beam computed tomography (EBCT) angiography and X-ray catheter angiography (CAG). We performed a blinded study where patients who previously underwent CAG with (n = 14) and without (n = 14; age- and gender-matched controls) anomalous coronary anatomy were studied with EBCT coronary angiography. Forty to 50 EKG-triggered 3 mm overlapping axial slices were acquired with 2 mm table movement within one breath hold during the i.v. injection of 140 cc of nonionic iodinated contrast (4 ml/sec). The axial source images and volume-rendered three-dimensional reconstructions were evaluated for the presence, type, and course of coronary anomalies and the results were compared to those of CAG. All normal and anomalous coronary arteries were identified by both modalities in all subjects. Identified anomalies include single coronary artery (n = 3), left-sided right coronary artery (n = 3), right-sided left main coronary artery (n = 3), anterior descending coronary artery (n = 2), circumflex coronary artery (n = 2), and separate left-sided ostia for left anterior descending and circumflex coronary arteries (n = 1). In five cases, there was discrepancy in the course of the anomalous vessels between the two modalities. Consensus reading among cardiologist and radiologists favored the interpretation of EBCT over catheter angiography. Noninvasive EBCT coronary angiography compares well with CAG in identifying anomalous coronary arteries and may provide confirmatory evaluation of their precise anatomic relationships to the heart and great vessels.     

Noninvasive coronary angiography by contrast-enhanced electron beam computed tomography

Electron beam computed tomography (EBCT) is a cross-sectional imaging method with high temporal and spatial resolution. So far, it has mainly been applied for the detection of coronary artery calcifications which permit the very sensitive detection of coronary atherosclerosis even in the very early stages. However, after intravenous injection of a contrast agent, EBCT also permits the direct visualization of the coronary artery lumen. For these investigations, a volume data set is acquired that consists of 40 axial cross-sections of the heart (3 mm slice thickness). To evaluate the coronary arteries as to the presence of stenoses and occlusions, various forms of postprocessing, including shaded surface display, maximum intensity projection, and multiplanar reconstruction, are applied. The sensitivities and specificities for the detection of coronary artery stenoses and occlusions are about 90%. Best results are obtained for coronary artery bypass grafts, the left main coronary artery, and the left anterior descending coronary artery, while reduced image quality impairs the results for the right coronary artery and the left circumflex coronary artery.     

Left main coronary artery aneurysm with chronic total occlusion of both left coronary arteries in a young athlete

Aneurysms of the left main coronary arteries are found in 0.1% of angiograms. This case involves an athlete with a left main coronary artery aneurysm, which was combined with chronic total occlusion of the proximal left anterior descending and proximal left circumflex coronary arteries. The extraordinary clinical presentation in this patient may be associated with good coronary collaterals, which may have developed in the patient in response to chronic total occlusion of the coronary artery by the aneurysm, and repeat myocardial hypoxia during high levels of performance as a soccer player.


Keywords: coronary aneurysm; left main coronary disease; intravascular ultrasonography; electron beam computed tomography     

Intravenous three-dimensional coronary angiography using contrast enhanced electron beam computed tomography

Coronary angiography remains the diagnostic standard for establishing the presence, site, and severity of coronary artery disease (CAD). Electron beam computed tomography (EBCT), with its 3-dimensional capabilities, is an emerging technology with the potential for obtaining essentially noninvasive coronary arteriograms. The purpose of this study was to (1) test the accuracy of intravenous coronary arteriography using the EBCT to conventional coronary arteriographic images; (2) establish the inter-reader variability of this procedure; (3) determine the limitations due to location within the coronary tree; and (4) identify factors that contributed to improved image quality of the 3-dimensional EBCT angiograms. Fifty-two patients underwent both EBCT angiography and coronary angiography within 2 weeks. The coronary angiogram and the EBCT 3-dimensional images were analyzed by 2 observers blinded to the results of the other techniques. EBCT correctly identified 43 of 55 significantly stenosed arteries (sensitivity 78%), and correctly identified 118 of 130 of the nonobstructed arteries, yielding a specificity of 91% (p <0.001, chi-square analysis). The overall accuracy for EBCT angiography was 87%. Significantly more left main and anterior descending coronary arteries were adequately visualized than the circumflex and right coronary vessels (p = 0.003). Overall, 23 of 208 (11%) major epicardial vessels were noninterpretable by the blinded EBCT readers, primarily due to motion artifacts caused by cardiac and respiratory motion and poor electrocardiographic gating. The inter-reader variability was similar to that of angiography, and its high accuracy makes this a clinically useful test. This study demonstrates, by using intravenous contrast enhancement, that EBCT can clearly depict the coronary artery anatomy and can permit identification of coronary artery stenosis.     

Noninvasive imaging of coronary arteries with electron beam tomography (EBCT)

Coronary angiography remains the diagnostic standard for establishing the presence, site, and severity of coronary artery disease. Electron beam computed tomography (EBCT), a non-invasive imaging method with very high spatial and temporal resolution, is well suited for cardiac imaging. Using a standard protocol, EBCT permits the visualization of the coronary arteries. Stenoses and occlusions of the native arteries and of coronary artery bypass grafts can be reliably diagnosed. Extremely calcified segments have to be excluded from evaluation. Reduced image quality, mainly due to fast vessel motion and superposition of large veins, impairs the results obtained for the right and left circumflex coronary artery. Possible clinical applications are the follow-up after angioplasty (PTCA without stent) and bypass surgery, the exclusion of coronary artery disease in patients with low likelihood of disease, and the evaluation of coronary anomalies.     

Noninvasive visualization of atherosclerotic plaque with electron beam and multislice spiral computed tomography

As an alternative to intracoronary modalities, electron beam computed tomography (EBCT) and multislice spiral computed tomography (MSCT) are able to noninvasively image the coronary arteries. In addition to stenosis detection by imaging the vessel lumen, MSCT has the ability to visualize the coronary artery wall. By using computed tomography (CT), the various components of atherosclerotic plaque may be distinguished and characterized, which holds the promise of, eventually, identifying vulnerable plaque.     

Will Noninvasive Techniques Replace Coronary Angiography?

Electron beam computed tomography (EBCT) and magnetic resonance imaging (MRI) represent modern noninvasive imaging technologies. MRI in particular has improved diagnosis of many extracardiac diseases. It is claimed that these technologies are superior to the established technique of coronary angiography (CA) for diagnosis of coronary artery disease (CAD) because they are easily repeatable, eliminating the risk of an invasive procedure, and potentially cost saving. Both EBCT and MRI have produced excellent images of proximal coronary arteries. However, their imaging precision is far from that of CA, especially for distal artery segments and the left circumflex and right coronary arteries. An improved image quality probably will be achieved in the future. However, for the next several years CA is essential for diagnosis of CAD and planning of therapy. In selected patients, MRI will provide additional information to angiographic and echocardiographic data (e.g., for assessment of coronary flow, myocardial viability, and morphology of extracardiac vessels). For reasons of cost containment, in many patients with CAD the simultaneous procedure of diagnostic CA and therapeutic angioplasty seems more reasonable than the additional expensive performance of EBCT and MRI.     

Noninvasive coronary artery imaging in the diagnosis and management of patients with ischemic heart disease.

The inherent limitations of x-ray coronary angiography have led to the development for both noninvasive and minimally invasive techniques for imaging the coronary arteries to assist in the diagnosis and management of patients with ischemic heart disease. Significant advances in transesophageal echocardiography, electron beam computed tomography, and magnetic resonance imaging now permit imaging of the proximal to mid-coronary arteries. Moreover, results of initial studies demonstrate the promise of these methods to detect coronary artery stenoses. In addition, each of these methods provides biochemical or physiologic data about the stenoses that are not obtainable through x-ray angiography. Quantification of coronary calcification via electron beam computed tomography has shown promise as a surrogate marker of coronary atherosclerosis. Transesophageal echocardiography and magnetic resonance imaging appear useful in evaluating the physiologic significance of angiographically detectable coronary artery stenoses via assessment of coronary blood flow. However, it should be noted that significant improvements in technology or acquisition parameters must occur before these techniques can be used on a routine clinical basis for coronary artery imaging. The relative merits and ultimate clinical potential of each of these techniques are discussed in this article.     

电子束CT检测冠状动脉钙化对诊断老年冠心病的价值

目的　探讨电子束CT检测冠状动脉钙化 (CAC)对诊断老年人冠心病的价值。方法　 2 2 9例老年患者行电子束CT检测CAC并计算每例的CAC总积分 ,行选择性冠状动脉造影以确定冠状动脉粥样硬化狭窄的有无及其程度。结果　 (1) 2 2 9例患者中 ,CAC检测阳性 2 2 0例 ,总阳性率 96 .0 7% ;造影显示有 2 13例存在不同程度的冠状动脉狭窄 ,其中 16 8例确诊为冠心病。 (2 )全组CAC诊断老年人冠心病的总体敏感性、特异性、阳性预测值和阴性预测值分别为 99%、13%、76 %和 89% ,诊断老年人冠状动脉粥样硬化的相应指标则分别为 97%、19%、94%和 33%。(3)老年男性组CAC诊断冠心病的敏感性较高特异性较低 ;老年女性则特异性较高而敏感性较低。综合考虑敏感性及特异性 ,对于老年男性 ,以CAC积分为 2 0 0作为诊断冠心病的分值较好 ,而对于老年女性则以 5 0作为诊断分值较佳。结论　电子束CT检测冠状动脉钙化对诊断老年人冠心病具有一定价值 ,但应结合性别和钙化分值进行综合分析。     

Coronary artery disease in Chinese adults with type 2 diabetes mellitus estimated by electron beam computed tomography and electron beam computed tomography angiography

Objective To assess the prevalence and risk of coronary artery disease(CAD) in Chinese adults with type 2 diabetes mellitus(T2DM) using electron beam computed tomography(EBCT) and EBCT angiography(EBCTA) . Methods:Ninety-four cases were enrolled in this study including diabetes(n=28) ,impaired glucose tolerance(IGT,n=30) ,coronary heart disease(CHD,n=11) ,and control(n=25) . Cardiac EBCT plain scanning and EBCTA were performed on all of these subjects to evaluate coronary artery calcifica-tion(CAC) scores,and number of segments of stenosed coronary arteries. Both CAC and/or coronary artery stenosis were defined as patients with coronary artery lesions(CAL) . Results CAC scores were not different with the control,diabetes,IGT,or CHD(P>0.05) groups. Compared to control(0.520±1.295) ,more stenosed coronary arteries segments(P<0.05) were detected in diabetes(2.964± 1.915) ,IGT(2.200±2.024) ,and CHD(2.273±1.679) . Number of stenosed artery segments were correlated with age(r=0.215,P=0.019) ,postprandial glucose(r=0.224,P=0.015) ,total cholesterol(r=0.323,P=0.000) ,and duration of diabetes(r=0.208,P=0.004) . The incidences of CAL in diabetes(96.43%) ,IGT(93.33%) ,and CHD(90.91%) was substantially higher than that in normal control(56.00%,P<0.01) . The odds ratio of CAL associated with having diabetes was estimated to be 7.514(95% CI:1.885-63.778) . Conclusions Coronary artery lesions are prevalent in Chinese adults with type 2 diabetes,implying a high CAD risk. EBCTA holds potential in depicting the details of CAL and can be used to track the progression of CAD in diabetes patients.     

电子束CT在疑诊冠心病胸痛鉴别诊断中的意义

目的　探讨电子束CT(EBCT)在疑诊冠心病胸痛鉴别诊断中的作用。方法　对 86例以胸痛为主要症状、临床疑诊为冠心病心绞痛者做EBCT检查冠状动脉钙化、冠状动脉造影、平板运动试验和 2 4小时动态心电图检查。结果　冠状动脉造影狭窄组冠脉钙化总积分明显高于无狭窄组 (P <0 0 5 ) ;X综合征患者冠状动脉亦存在不同程度钙化 ,但低于冠状动脉狭窄者 ;冠状动脉无钙化者心绞痛症状不典型 ,平板运动试验阴性 ,冠脉造影正常。结论　结果提示EBCT在冠心病心绞痛的诊断中有较大的意义 ,即无钙化者有可能排除冠心病心绞痛的诊断。     

Effect of exercise on left and right ventricular ejection fraction and wall motion.

OBJECTIVE: We evaluated the diagnostic value of response of left and right ventricular ejection fraction and wall motion to exercise using electron beam computed tomography. METHODS AND RESULTS: We attempted to determine the value of exercise electron beam computed tomography for detecting coronary artery disease, including evaluation of the right ventricular ejection fraction and wall motion abnormalities. A study of 35 patients undergoing electron beam tomography exercise cine studies and coronary artery angiography for the evaluation of chest pain was performed. Of the 18 patients with significant coronary disease (> or = 50% luminal diameter stenosis in at least one coronary artery), 17 (94%) had failure to increase global left ventricular ejection fraction with exercise. Fourteen of 18 (78%) developed a wall motion abnormality during peak exercise, and eight (44%) developed a regional right ventricular wall motion abnormality during peak exercise. Of the 17 patients without obstructive disease, 14 (82%) had a increase in ejection fraction > or = 5% and none had an abnormal response in left ventricular wall motion during peak exercise (specificity = 100%). The change in right ventricular ejection fraction with exercise was not a significant predictor of obstructive coronary disease in this study (P=NS). Using different criteria during stress to predict coronary disease, the accuracy was 89% (31/35) using an increase of <5% in ejection fraction, 89% (31/35) using the development of a new or worsened wall motion abnormality, and 91% (32/35) using both left ventricular criteria. CONCLUSION: Our study suggests that exercise electron beam computed tomography appears to be a useful tool for the detection of coronary disease. A increase of <5% in ejection fraction and abnormal left ventricular response to exercise were important predictors, while the exercise induced changes of right ventricular ejection fraction was not a significant predictor of obstructive disease. Both left and right ventricular wall motion abnormalities are useful and important parameters in identifying patients with obstructive disease from those with normal coronary arteries.     

电子束CT冠状动脉钙化与影像学斑块负荷的量化关系

探讨经电子束CT检测的冠状动脉钙化积分与影像学斑块负荷的量化关系。 32 0例临床疑诊为冠心病而行选择性冠状动脉造影的患者行电子束CT检查 ,并计算冠状动脉钙化积分 ,分析钙化积分与冠状动脉粥样斑块负荷之间的关系。结果发现 ,全组冠状动脉钙化积分为 0～ 3 346 ,中位数 45 ,钙化积分的自然对数转换值平均为 3 .64± 2 .1 8。钙化积分的自然对数转换值与狭窄程度呈轻度正相关 (r=0 .385 ,P <0 .0 0 1 ) ,与斑块负荷总分呈高度正相关 (r=0 .768,P <0 .0 0 1 )。结果提示 ,电子束CT检测的冠状动脉钙化积分与斑块负荷之间有良好的相关性 ,而与狭窄程度的相关性较差。     

Exercise testing and electron beam computed tomography in the evaluation of coronary artery disease

OBJECTIVES: This study compared coronary artery calcium (CC) as detected by electron beam computed tomography (EBCT) with conventional stress testing in the evaluation of patients with symptoms suggestive of coronary artery disease (CAD). BACKGROUND: Exercise electrocardiogram treadmill stress testing (treadmill-ECG) is limited by its requirement of a normal resting ECG and the ability of the patient to exercise adequately. The addition of myocardial imaging agents such as technetium improves the sensitivity and specificity but substantially increases the cost and prolongs the testing time. The use of EBCT provides a noninvasive and rapid method for identifying the presence and amount of CC, which has been shown to be related to atherosclerosis, and may provide additional information in combination with more traditional noninvasive testing methods. METHODS: A total of 97 patients underwent technetium stress testing (technetium-stress), treadmill-ECG, and EBCT coronary scanning within three months of coronary angiography for the evaluation of chest pain. RESULTS: The relative risk (RR) of obstructive angiographic CAD for an abnormal test was higher for EBCT (4.53) than either treadmill-ECG (1.72) or technetium-stress (1.96). The low specificity of EBCT (47%) was improved by the addition of treadmill-ECG (83%, p < 0.05). CONCLUSIONS: Electron beam computed tomography has a higher diagnostic ability than either treadmill-ECG or technetium-stress for the detection of obstructive angiographic CAD. Electron beam computed tomography is an accurate and noninvasive alternative to traditional stress testing for the detection of obstructive CAD in symptomatic patients.     

A young woman with chest pain

A case of a previously fit young woman admitted with chest pain, who was found at coronary angiography to have dissection of the left main stem which extended to the left anterior descending and circumflex coronary arteries, is presented. Emergency coronary artery bypass grafting was performed (vein grafts to the left anterior descending, the diagonal, and circumflex arteries). The patient made an uneventful recovery, and three years after initial presentation she remains free of cardiac symptoms.


Keywords: spontaneous coronary artery dissection     

多层面螺旋CT冠状动脉成像在冠心病中的应用

目的　评价多层面螺旋CT(MSCT)行冠状动脉血管造影和三维重建在冠心病中的应用价值。方法　对 30例冠心病患者进行了心电门控MSCT增强扫描 ,在工作站对图像资料进行了最大密度投影法 (MIP)三维重建 ,并与冠状动脉造影结果相对照。结果　 30例患者中对 12 0支冠状动脉血管 (左主干、左前降支、回旋支、右冠状动脉 )进行了MSCT三维重建 ,图像质量良好者为 84支 (70 % ) ,影响图像质量的主要因素是心脏搏动造成的伪影 ;9例冠状动脉支架和 5例冠状动脉搭桥术后均可清晰显示支架和血管桥的位置及远端血流情况 ,对于显示近中端高度 (>75 % )或完全梗阻性病有一定的准确性 (敏感性 80 % ,特异性 79.8% )。而不能显示轻度狭窄病变、远端或细小分支病变。结论　MSCT血管造影和三维重建在冠心病诊断和对病变血管的评价 ,以及血运重建术后复查等方面有一定的应用价值。     

Standard versus user-interactive assessment of significant coronary stenoses with multislice computed tomography coronary angiography

Forty-four patients in sinus rhythm with suspected coronary artery disease underwent 16-row multislice computed tomography coronary angiography and conventional coronary angiography. Two protocols for image analysis were applied to the multislice computed tomographic images: standard projections versus interactive postprocessing. The diagnostic accuracy of both methods for the detection of significant lesions (>50% lumen reduction) was compared with quantitative coronary angiography. Sensitivity and specificity were 58% and 96% and 96% and 97%, for standard projections and interactive postprocessing protocol, respectively.