Evaluation of Cardiac Mitochondrial Function by a Nuclear Imaging Technique using Technetium-99m-MIBI Uptake Kinetics

Mitochondria play an important role in energy production for the cell. The proper function of a myocardial cell largely depends on the functional capacity of the mitochondria. Therefore it is necessary to establish a novel and reliable method for a non-invasive assessment of mitochondrial function and metabolism in humans. Although originally designed for evaluating myocardial perfusion, (99m)Tc-MIBI can be also used to evaluate cardiac mitochondrial function. In a clinical study on ischemic heart disease, reverse redistribution of (99m)Tc-MIBI was evident after direct percutaneous transluminal coronary angioplasty. The presence of increased washout of (99m)Tc-MIBI was associated with the infarct-related artery and preserved left ventricular function. In non-ischemic cardiomyopathy, an increased washout rate of (99m)Tc-MIBI, which correlated inversely with left ventricular ejection fraction, was observed in patients with congestive heart failure. Increased (99m)Tc-MIBI washout was also observed in mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and in doxorubicin-induced cardiomyopathy. Noninvasive assessment of cardiac mitochondrial function could be greatly beneficial in monitoring possible cardiotoxic drug use and in the evaluation of cardiac damage in clinical medicine.