[Noninvasive diagnostic of coronary artery disease]

Abstract

Noninvasive imaging of coronary artery disease has extensively evolved during the last decade. Today, at least four imaging techniques with excellent image quality such as echocardiography, myocardial perfusion scintigraphy and PET, cardiac magnetic resonance and cardiac CT are widely available in order to estimate the risk for future ischemic events, to corroborate the suspected diagnosis of coronary artery disease, to demonstrate the extent and localisation of myocardial ischemia, to diagnose myocardial infarction and measure it's size, to identify the myocardium at risk during acute ischemia, to differentiate between viable and nonviable myocardium and thereby provide the basis for indications of revascularisations, to follow revascularized patients over long time, to assess the risk for sudden cardiac death and the development of heart failure after myocardial infarction and to depict atheromatosis and atherosclerosis of the coronary artery tree. Echocardiography is the most widely used imaging method in cardiology. It provides excellent information on morphology and function of nearly all cardiac structures. Stress echocardiography has been proven to be a reliable tool for the demonstration of myocardial ischemia and for the acquisition of prognostic data. Newer ultrasound techniques may further improve investigator dependence and thereby reproducibility. The completeness of echocardiography will always depend on acoustic windows, which are given in a specific patient. Myocardial perfusion scintigraphy provides the largest database especially on prognosis in coronary artery disease. It has been the <<work horse>> for the depictions of ischemic and infarcted myocardium. Radiation exposure will always be an issue. Newer hybrid techniques combining nuclear methods with cardiac CT may add arguments, which will be needed for clinical decision-making. Cardiac magnetic resonance has evolved as an important tool in the diagnosis of cardiovascular diseases. It is investigator independent, does not apply any biologically hazardous energy and has the largest potential for tissue characterization due to its high contrast resolution. It therefore is an excellent technique to investigate all the aspects of coronary artery disease. Its availability is increasing, however in order to fully utilize its large potential an optimal collaboration among -specialist (cardiologists, radiologists, physicists) is mandatory. Cardiac CT has evolved as an excellent method for the depiction of the coronary arteries. Due to its high spatial and time resolution it provides high quality luminography of the coronaries and newer technique are also -investigating plaque composition of diseased coronary arteries. Overestimation of coronary artery stenosis in calcified vessels is an inherent problem of the technique and the risk of radiation exposure has to be weighted against the benefit of non-invasively depicting the coronary arteries. It will be the future task of all specialists in this field to define the most efficient and cost-effective way to apply these excellent techniques for the investigation of all the different aspects of patients with coronary artery disease.