The aim of the study is to evaluate and compare the value of 5 different non-invasive diagnostic methods in patients with chest pain suspected for coronary artery disease. The investigators intend to include 200 patients over a 3 year period in the study. The participants will be recruited from patients referred to coronary angiography at the institution. Before the angiography the participants will (1) test the effect of sublingual Nitroglycerin, (2) give their medical history so mathematical models can estimate the probability of the presence of coronary artery disease, (3) take part in a contrast stress echocardiography and (4) a 2D-strain stress echocardiography and a myocardial scintigraphy. Stenosis found at the angiography will be the gold standard.