Myocardial Perfusion Imaging (MPI) and Coronary Angiography (CA) are two methods that can be used in the investigation of ischemic heart disease. The purpose of this study is to compare medical answers from MPI and CA to find out if suspected coronary artery disease shown with MPI correlates with coronary artery morphology shown with CA, and which treatment is given based on Summed Difference Percent (SD%). The study population consists of 45 patients. The information has been retrieved retrospectively at Länssjukhuset Ryhov. Included patients had coronary heart disease accessible for percutan coronary intervention. Out of the total data sample the results show an occurring difference when it comes to medical answers from MPI and CA. The results show that most of the study participants with SD% <10 obtained solely drug treatment. Those with SD% >10 were given treatments not always according to guidelines. Elements that might have had an impact on the result is discussed. In conclusion, it appears that there is a difference in some medical answers which may be a caused of collateral circulation which causes the wrong coronary artery area to be determined as ischemic based on the MPI or because of a misinterpretation of an exam.