Single coronary artery syndrome: Cardiac computed tomography angiography as a leading imaging modality

Single coronary artery syndrome is usually an asymptomatic condition in most patients; thus most patients are diagnosed when noninvasive imaging (cardiac computed tomography angiography, cardiac magnetic resonance) or invasive coronary angiography is done for evaluation for other cardiac conditions. With advances using cardiovascular imaging in the evaluation and management of single coronary artery syndrome; Cardiac Computed Tomography Angiography (CCTA) has emerged as a very essential and leading imaging modality. CCTA has the best resolution (spatial and temporal) among the imaging modalities available for analyzing the cardiovascular system for the diagnosis and management of single coronary artery syndrome. We are presenting cases of patients with single coronary artery syndrome with 3 different courses (anterior, septal, inter‐arterial), illustrating how CCTA gives a detailed anatomic/structural evaluation of the origin and course of the coronary arteries, and other cardiac structures. Thus in patients diagnosed with single coronary artery syndrome, CCTA can provide vital information on the not only the course, but the associated narrowing of coronary vessels. © 2011 Wiley‐Liss, Inc.     

Multislice computed tomography angiography in the diagnosis of coronary artery disease

Multislice CT angiography represents one of the most exciting technological revolutions in cardiac imaging and it has been increasingly used in the diagnosis of coronary artery disease. Rapid improvements in multislice CT scanners over the last decade have allowed this technique to become a potentially effective alternative to invasive coronary angiography in patients with suspected coronary artery disease. High diagnostic value has been achieved with multislice CT angiography with use of 64- and more slice CT scanners. In addition, multislice CT angiography shows accurate detection and analysis of coronary calcium, characterization of coronary plaques, as well as prediction of the disease progression and major cardiac events. Thus, patients can benefit from multislice CT angiography that provides a rapid and accurate diagnosis while avoiding unnecessary invasive coronary angiography procedures. The aim of this article is present an overview of the clinical applications of multislice CT angiography in coronary artery disease with a focus on the diagnostic accuracy of coronary artery disease; prognostic value of coronary artery disease with regard to the prediction of major cardiac events; detection and quantification of coronary calcium and characterization of coronary plaques. Limitations of multislice CT angiography in coronary artery disease are also briefly discussed, and future directions are highlighted.     

Coronary Angiography Using Noninvasive Imaging Techniques of Cardiac CT and MRI

Noninvasive coronary angiography has become an important imaging tool in the evaluation of patients with and at risk for coronary artery disease (CAD). Multidetector computed tomographic (MDCT) angiography offers excellent negative predictive value (≥95%) for the absence of coronary artery disease and has shown promising results in evaluating allograft vasculopathy, bypass grafts, and degenerative aortic valve disease. A single MDCT scan in the emergency department is valuable in ruling out both cardiac and noncardiac causes of acute chest pain. Cardiac magnetic resonance (MR) currently lacks the spatial resolution of MDCT limiting its assessment of the coronary vasculature, but the proximal coronary arteries can be evaluated along with myocardial function and viability without exposure to contrast dye or ionizing radiation. In addition, MR imaging also has great potential for characterizing coronary plaques, as well as following their progression and regression.Key Words: Coronary angiography, cardiac computed tomography, magnetic resonance imaging.     

Ischemic heart disease: value of MR techniques

Background. The cardiovascular applications of magnetic resonance (MR) techniques in coronary artery disease have increased considerably in recent years. Technical advantages of MR imaging are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. These characteristics allow the accurate assessment of left ventricular mass and volume, the differentiation of infarcted from normal tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. Methods. In addition to the conventionally used spin-echo and cine-echo techniques, newer techniques such as myocardial tagging, ultrafast MR imaging and MR coronary angiography have been developed. These newer techniques allow a more accurate assessment of ventricular function (tagging), myocardial perfusion (ultrafast imaging), and evaluation of stenosis severity (MR coronary angiography). Particularly early detection and flow assessment of stenosed coronary arteries and bypasses by MR angiography would constitute a major breakthrough in cardiovascular MR imaging. Apart from the MR imaging techniques, cardiac metabolism may be well assessed using MR spectroscopy. This provides unique information on the metabolic behaviour of the myocardium under conditions stress-induced ischemia. However, the definite niche of cardiac MR spectroscopy has still to be settled. Conclusion. Currently, MR techniques allow the evaluation of anatomy and function (accepted use), perfusion and viability (development phase), and coronary angiography (experimental phase). A particular strength of MR imaging is that one single MR test may encompass cardiac anatomy, perfusion, function, metabolism and coronary angiography. The replacement of multiple diagnostic tests with one MR test may have major effects on cardiovascular healthcare economics and would outweigh the cost inherent to the MR angiography procedure.     

Diagnosis of graft coronary artery disease

PURPOSE OF REVIEW: Graft coronary artery disease is the leading cardiac cause of death in patients who have undergone cardiac transplantation. Due to denervation, classic symptoms of angina are not reliable. Many transplant centers have a protocol of routine annual surveillance cardiac angiography because treatment options are limited, especially with advanced disease. Angiography is an assessment of the arterial lumen, however, and can miss nonfocal disease. This paper reviews invasive and noninvasive diagnostic tools for graft coronary artery disease. Intravascular ultrasound is the most sensitive, but the cost and lack of widespread expertise make it unpopular. Noninvasive techniques have been studied. An ideal test would be sufficiently sensitive to detect disease and allow for prognostic information. Dobutamine echocardiography is the most sensitive noninvasive test but can have a high false-positive rate. It is also not universally available. Exercise nuclear imaging is specific and can be used as a confirmatory test in patients with positive dobutamine echocardiograms. RECENT FINDINGS: Computed tomographic imaging and cardiac magnetic resonance imaging are exciting new modalities but require further study. SUMMARY: There is no test sensitive and specific enough yet that can be confidently used to replace coronary angiography.     

正电子发射断层扫描与X线断层扫描在冠状动脉性心脏病中的应用和进展

冠状动脉粥样硬化性心脏病是许多国家首要的死亡原因,正电子发射断层扫描可以清晰地显示心肌灌注,室壁运动和心肌活性,成为诊断冠状动脉粥样硬化性心脏病的重要手段。而正电子发射断层扫描和多层螺旋X线断层扫描仪的融合,把钙化积分和无创性的X线断层扫描仪血管造影加入心肌灌注显像和代谢显像,为冠状动脉粥样硬化性心脏病的诊断提供形态和功能方面的信息。     

Current Role of Cardiac Computed Tomography

The introduction of recent generations of multidetector computed tomography scanners has brought about substantial improvements in spatial and especially temporal resolution which have made imaging of the heart and, under certain conditions, visualization of the coronary arteries possible. Non-enhanced scans allow visualization of cardiac and coronary artery calcification. After intravenous injection of contrast agent, it is possible to visualize cardiac chambers and to analyze the coronary artery lumen.Morphological imaging of the heart, for example in the context of congenital heart disease, is possible by computed tomography (CT) and can, in some very selected cases, be clinically useful as an adjunct to echocardiography or magnetic resonance imaging. Functional imaging allows to analyze left and right ventricular function by CT.CT plays a more prominent clinical role in the context of coronary artery visualization. Coronary calcifications are indicative of coronary atherosclerosis and the presence and amount of coronary artery calcium have a strong predictive value concerning future cardiovascular events, even in asymptomatic individuals. It can potentially be used for refined risk stratification. Contrast-enhanced "CT coronary angiography" has become quite reliable under certain conditions (e.g., a low heart rate). The negative predictive value to rule out coronary artery stenoses has been found to be high in several studies. Therefore, clinical utility to rule out significant coronary artery stenoses in patients who are symptomatic, but have a low to intermediate pretest likelihood of disease is assumed. Ideally, "negative" coronary angiograms would be avoided by using coronary CT angiography. Large-scale trials that would pinpoint specific patient groups to benefit from "CT coronary angiography" are currently lacking.     

Intracoronary imaging in addition to coronary angiography for patients with out-of-hospital cardiac arrest: More information for better care?

About 70% of out-of-hospital cardiac arrests are related to an ischaemic heart disease in Western countries. Percutaneous coronary intervention has been shown to improve the prognosis of survivors when an unstable coronary lesion is identified as the potential cause of the cardiac arrest. Acute complete coronary occlusion is often demonstrated among patients with ST-segment elevation on electrocardiogram after the return of spontaneous circulation. In patients without ST-segment elevation, routine coronary angiography has been shown to be not superior to conservative management. However, an electrocardiogram-based decision to perform immediate coronary angiography could be insufficient to identify unstable coronary lesions, which are frequently associated with intermediate coronary stenosis. Intracoronary imaging can be helpful to detect plaque rupture or erosion and intracoronary thrombus, but could also lead to better stent implantation, and help to reduce the risk of stent thrombosis. In patients with coronary lesions without the instability characteristic, conservative management should be the default strategy, and a search for another cause of the cardiac arrest should be systematic. In the present review, we sought to describe the potential benefit of intracoronary imaging in patients with out-of-hospital cardiac arrest.     

Three-dimensional coronary anatomy in contrast-enhanced multislice computed tomography

A number of three-dimensional imaging modalities, such as magnetic resonance imaging, electron beam computed tomography, ultrasonography, and multislice computed tomography have been introduced in cardiovascular medicine. One of the most recently developed techniques, multislice computed tomographic coronary angiography, allows assessment of the small coronary vessels. The entire heart is scanned within a single breathhold and contrast-enhanced images are reconstructed through retrospective electrocardiographic gating. Instead of the conventional two-dimensional projection images, multislice computed tomographic data can be displayed in a three-dimensional, volume-rendered manner. This paper presents an overview of the cardiac and coronary morphology as it is imaged with contrast-enhanced multislice computed tomography. Further imaging characteristics of computed tomographic angiography are discussed.     

Cardiovascular computed tomographic angiography evaluation following unsuccessful invasive angiography: The clinical utility of 3D volume rendering

In an appropriate clinical setting, cardiac CT angiography (CCT) can be used as a safe and effective noninvasive imaging modality for defining coronary arterial anatomy by providing detailed three‐dimensional anatomic information that may be difficult to obtain with invasive coronary angiography (ICA). We present a patient where coronary angiography by ICA was unsuccessful and where the subsequent CCT proved to be very useful in providing us relevant information. © 2009 Wiley‐Liss, Inc.     

Cardiac and coronary CT comprehensive imaging approach in the assessment of coronary heart disease

Cardiac CT is a rapidly advancing technology. Non-invasive CT coronary angiography is an established technique for assessing coronary heart disease with accuracy similar to invasive coronary angiography. CT myocardial perfusion imaging can now identify perfusion defects in animal models and humans. MRI is the current 'gold standard' for the assessment of myocardial viability, but it is now also possible to assess delayed enhancement by CT. This has led to the possibility of a 'one-stop shop' for cardiovascular imaging that would provide information on anatomy, function, perfusion and viability in one rapid diagnostic test at a radiation dose equivalent to contemporary nuclear medicine imaging. This review discusses the current status of 'one-stop shop' cardiac CT assessment, clinical utility and directions for future research.     

Transesophageal echocardiographic assessment of coronary stenosis: a decade of experience

Coronary artery imaging is routinely obtained invasively at cardiac catheterization through coronary angiography. This remains the gold standard, but with advances in ultrasound technology, electron beam computed tomography, and magnetic resonance imaging, newer noninvasive methodologies are achieving greater success at imaging the coronary anatomy. This review is meant to highlight the important accomplishments from transesophageal echocardiographic (TEE) investigations that have studied the coronary arteries. The specific technique for optimally imaging the coronaries with high frequency transducers, color and conventional Doppler, in addition to contrast-enhanced methods, will be analyzed. Importantly, this article serves as a reminder to echocardiographers and cardiologists that excellent, clinically relevant information of the coronary arteries can be obtained routinely during TEE. This technique is part of the trend noted by the other authors in this special edition; that is, echocardiography is becoming the gold standard of the new millennium for many diagnostic areas, even coronary angiography.     

CT of coronary artery disease

The clinical relevance of coronary artery disease has considerably driven the recent development of radiologic tools for noninvasive cardiac imaging. Modern multidetector row computed tomographic (MDCT) systems combine high temporal and spatial resolution, electrocardiographic synchronization, and ease of use. In cardiac imaging, MDCT has not only replaced electron-beam CT, but also challenges competing methods such as magnetic resonance imaging, echocardiography, or even coronary catheterization. Noncontrast material-enhanced assessment of atherosclerotic plaques (CT calcium scoring) seems useful for the cardiac risk stratification in asymptomatic patients and monitoring of medical (statin) therapy. Contrast material-enhanced CT coronary angiography has become established as a valuable method for several clinical indications such as evaluation of coronary artery anomalies, bypass patency, or preoperative planning. Particularly, the high negative predictive value of a normal CT coronary angiogram allows reliable exclusion of coronary artery stenosis. Plaque characterization is another promising area of research in MDCT cardiac imaging. However, with current technology a reliable distinction between atheroma and fibroatheroma is impaired by restrictions in spatial resolution. Recent studies indicate that CT angiography may also be suited for other clinical applications such as triage of patients with acute coronary syndrome and inconclusive clinical presentation, patients with symptomatic chest pain, and intermediate risk profile or cardiac risk stratification in asymptomatic patients.     

Multimodal Imaging after Sudden Cardiac Arrest in an 18-Year-Old Athlete

We report the case of a previously healthy 18-year-old male athlete who twice presented with sudden cardiac arrest. Our use of electrocardiography, echocardiography, cardiac magnetic resonance, coronary angiography, coronary computed tomographic angiography, and nuclear stress testing enabled the diagnoses of apical hypertrophic cardiomyopathy and anomalous origin of the right coronary artery. We discuss the patient''s treatment and note the useful role of multiple cardiovascular imaging methods in cases of sudden cardiac arrest.     

One-stop cardiovascular diagnostic imaging (and radiation dose)

Kefer et al. indicate that "MSCT and MR are useful for the noninvasive detection of coronary artery stenoses on both a segmental and per vessel basis. Because neither technique is 100% accurate, these techniques are not ready yet to replace conventional coronary angiography." In summary, all things considered, a properly done cardiac catheterization with contrast angiography can really be a one-stop shop for diagnostic imaging and therapy of the cardiovascular system, and the radiation dose is acceptable.     

Multimodality Imaging of a Giant Right Coronary Artery Aneurysm

We describe a case of a 54-year-old woman who had a right cardiac mass found on coronary angiography. Echocardiography, computed tomography, and cardiac magnetic resonance imaging characterized it as a thrombosed giant right coronary artery aneurysm. This was confirmed on pathology. We present the role of multimodality cardiovascular imaging in the diagnosis and characterization of a giant coronary artery aneurysm.     

Comprehensive cardiac CT study: evaluation of coronary arteries, left ventricular function, and myocardial perfusion--is it possible?

With advances in multidetector computed tomography (MDCT) technology, the new generation of 64-slice MDCT scanners with submillimeter collimation and a faster gantry rotation allows imaging of the entire heart in a single breath-hold with excellent temporal and spatial resolution. This potentially permits a comprehensive assessment of coronary anatomy, left ventricular function, and myocardial perfusion. As will be seen in this review of the current literature regarding 16- and 64-slice MDCT, there is great promise for a comprehensive cardiac computed tomography (CT) study. The available data support the notion that CT coronary angiography may be an alternative to invasive coronary angiography in symptomatic patients with a low to intermediate likelihood of having coronary artery disease. By use of the same data acquired for CT coronary angiography, evaluation of global and regional left ventricular function and myocardial perfusion can be added to the MDCT evaluation without additional exposure to contrast medium or radiation and may provide a more conclusive cardiac workup in these patients. The potential applications and limitations of coronary stenosis detection, global and regional left ventricular function, and myocardial perfusion assessment by MDCT will be reviewed. The full potential of cardiac MDCT is just beginning to be realized.     

Prognostic value of I-123 metaiodobenzylguanidine imaging in vasospastic angina without significant coronary stenosis.

BACKGROUND: Myocardial imaging is widely used to detect coronary artery disease and to assess its prognosis. In vasospastic angina (VA), cardiac imaging can provide information on disease activity, which is related to cardiac events. The aim of this study was to clarify whether exercise thallium-201 imaging (Tl-SPECT) and 123I-metaiodobenzylguanidine imaging (MIBG) have prognostic value for patients with VA, but without significant coronary artery stenosis. METHODS AND RESULTS: One hundred and 5 patients who showed acetylcholine-induced coronary spasm, normal left ventricular function and no significant stenosis (<50%) underwent both symptom-limited Tl-SPECT and MIBG within 1 month. All patients were prescribed calcium antagonist during the follow-up period (mean 4.7 years). Exercise-induced ischemia was detected by Tl-SPECT in 53 patients and multivessel coronary spasm by coronary angiography in 33 patients. During the follow-up period, 1 patient died suddenly and another died of acute myocardial infarction (MI). Two patients developed nonfatal acute MI and 7 patients underwent emergency coronary angiography because of unstable angina. According to the baseline characteristics, VA with cardiac events showed a significantly higher heart-to-mediastinum ratio (H/M ratio) and a significantly lower MIBG washout rate than those without cardiac events (p<0.03 and p<0.02, respectively). Among 8 clinical variables, including coronary risk factors, exercise parameters and exercise-induced ischemia on Tl-SPECT and the MIBG delayed H/M ratio and washout rate, univariate Cox proportional hazard regression analysis showed that the high H/M ratio and reduced washout rate of MIBG were significant predictors of future cardiac events (relative risk (RR) =4, confidence interval (CI) =1.21-13.29, p<0.02 for H/M ratio and RR 0.92, CI 0.85-0.99, p<0.02 for washout rate). However, exercise-induced ischemia did not show any statistical significance. By multivariate Cox proportional hazard regression analysis, a reduced MIBG washout rate was the only significant predictor of future cardiac events (odds ratio =0.90, CI =0.82-1.00, p<0.04). CONCLUSION: MIBG imaging can identify high-risk patients, even among those with VA who were previously regarded as low risk. This result strongly supports the idea that cardiac sympathetic dysfunction contributes to coronary artery spasm leading to cardiac events.     

Pulmonary and cardiac involvement in Beh?et disease: 3 case reports.

Pulmonary and cardiac involvement in Beh?et disease is rare but can cause life-threatening complications. This report presents computed tomography and magnetic resonance angiography findings in 3 patients with Beh?et disease. Imaging findings were confirmed by surgery in 1 patient and by angiography in another. One patient had bilateral pulmonary artery aneurysms, 1 of which had already ruptured and had thrombosed. The other had unilateral pulmonary artery aneurysm and thrombosis accompanied with intracardiac thrombus formation. The third patient had unilateral pulmonary artery aneurysm, thrombus, and coronary artery aneurysm. As in our case, there have been rare reports of coronary artery disease and intracardiac thrombus formation associated with pulmonary vascular involvement. Noninvasive imaging modalities minimize any risk of endothelial damage and can be an alternative to angiography in assessment of pulmonary and cardiac involvement in Beh?et disease.     

Cardiac allograft vasculopathy: advances in diagnosis

Cardiac allograft vasculopathy (CAV), characterized by diffuse intimal thickening and luminal narrowing in the arteries of the allograft, is the leading cause of morbidity and mortality in cardiac transplant recipients. Many transplant centers perform routine annual surveillance coronary angiography. However, angiography can underdiagnose or miss CAV due to its diffuse nature. Intravascular ultrasound (IVUS) is more sensitive than angiography. IVUS provides not only accurate information on lumen size, but also quantification of intimal thickening, vessel wall morphology, and composition. IVUS has evolved as a valuable adjunct to angiography and the optimal diagnostic tool for early detection. Noninvasive testing such as dobutamine stress echocardiography and nuclear stress test have shown considerable accuracy in diagnosing significant CAV. Computed tomographic imaging and cardiac magnetic resonance imaging are promising new modalities but require further study. This article reviews the diagnostic methods that are currently available.