Myocardial perfusion with 99mTc-labeled tracers is clinical standard method to assess ischemic heart diseases. Mitochondria are responsible for ATP production to ensure myocardial function and contractility under the normal circumstances. MIBI retention in myocytes is strongly related to normal mitochondrial function to maintain the electrochemical potential on the outer surface of mitochondria. In a damaged myocardium, the impaired function of energy-production and transfer in mitochondria can result in rapid release of MIBI, which is called reverse redistribution.
It has been reported that delayed MIBI images within few hours can detect enhanced washout rate (WR) in impaired myocardium associated with cardiomyopathy.
WR using a planar image may be an effective index when the washout is determined in the whole myocardium in patients with myocardial disease. However, since the washout of MIBI is increased only in a region that is subject to a coronary artery occlusion in patients with ischemic heart disease.
Cardiomyopathy is a myocardial disease characterized by left ventricular or biventricular dilatation and impaired myocardial contractility and causes substantial morbidity and mortality, despite major therapeutic achievements.
It was identified that some patients with ischemic cardio myopathy (IDCM) had pathologic mutations in mitochondrial DNA. The mutations may be a sign of increasing stress to the heart, promoting consecutive damage to mitochondrial DNA, such defects may constitute the basis for the development of DCM and CHF. As 90% of 99mTc-MIBI is contained inside myocardial cells mitochondria and cytochrome c oxidase inhibitor sodium cyanide and sarcolemma membrane detergent resulted in an increase in the 99mTc MIBI clearance; it is suggested that the clearance of 99mTc MIBI can be used to assess ongoing myocardial damage in patients with ischemic cardiomyopathy.