Molecular imaging of myocardial remodeling after infarction.

Myocardial fibrosis after myocardial infarction plays a major role in cardiac remodeling, development of heart failure, and arrhythmias. Both replacement and interstitial fibrosis are determined by the extent of myofibroblastic proliferation and hence the extent of collagen deposition. It is logical to propose that a molecular imaging strategy that is able to determine the rate of myofibroblastic proliferation should be able to foretell the magnitude of myocardial remodeling and the likelihood of development of heart failure. Of various plausible targets on the proliferating myofibroblasts, receptors for neurohumoral agonists and overexpression of integrin moieties may offer best options for molecular imaging. In this chapter we describe the assessment of angiotensin II receptor and αvβ3 integrin upregulation in a mouse model after myocardial infarction using real time in vivo fluorescence imaging and nuclear imaging.