Visualization of altered myocardial lipids by 1H NMR chemical-shift imaging following ischemic insult.

Acute myocardial infarction is associated with an accumulation of lipids. Spectroscopic and chemical-shift imaging strategies which can depict the spatial distribution of these chemical species are evolving. The present study was undertaken to test whether the Dixon method could detect spatially lipids known to accumulate in myocardium after an ischemic insult. Seven dogs underwent a 24-h coronary artery occlusion (LAD = 4, Cx = 3). Post mortem, hearts were removed and imaged ex vivo. Myocardial samples were also evaluated by high-resolution 1H NMR spectroscopy. Lipid images revealed regions of increased signal intensity, in the regions corresponding to the myocardial infarction, particularly in the periphery of the infarction. An increase in mobile lipids was observed by 1H NMR spectroscopy of myocardial samples with moderately reduced blood flow and corresponding to regions with increased signal intensity on the lipid image. This study shows that chemical-shift imaging may be useful for detecting alterations in myocardial lipid levels following an ischemic insult.