Objective. The study addresses differentiation of ischemic and non-ischemic cardiomegaly by positron emission tomography (PET). Design and methods. Based on echocardiography data 50 patients with cardiomegaly and reduced systolic function were included in the study: 32 patients with coronary heart disease (CHD) and 18 patients with normal coronary arteries according to angiography results (6 of them had alcohol abuse). All patients underwent PET with [13N]-ammonia and [18F]-FDG for myocardial perfusion and metabolism evaluation. A semiquantitative analysis of the images was performed. Results. All patients with CHD showed large hypoperfusion areas (more than 3 segments) matching the coronary artery flow. Perfusion/metabolism match was revealed in all (100 %) patients with CHD and perfusion/metabolism mismatch was observed in 25 (79 %) patients of the same group. The patients with noncoronarogenic cardiomegaly (NCM) had diffuse heterogeneity of myocardial perfusion, 5 of them showed small and mild perfusion defects with non-segmental distribution. The areas of abnormal perfusion were significantly larger in cases of CHD. Perfusion/metabolism match was noted in 2 (11 %) patients with NCM and none of the patients with NCM showed perfusion/metabolism mismatch. Conclusion. Diffuse heterogeneity of myocardial perfusion, non-segmental distribution of perfusion defects and lack of perfusion/metabolism mismatch are the most important features of noncoronarogenic cardiomegaly as compared to ischemic cardiomegaly.
Positron emission tomo graphy imaging in the differentiatial diagnosis of cardio megaly of ischemic and noncoronarogenic origin
