Biexponential Diffusion Observed in Myocardial Tissue Slices

Introduction Recent interest in myocardial diffusion imaging has provided new information regarding the microstructural organization of the heart (1,2), as well as alterations in the apparent diffusion constant (ADC) of water that occur during myocardial ischemia (3). Moreover, the demonstration that myocardial diffusion imaging can be performed in vivo (4) has dramatic implications for clinical applications. Recent studies in brain slices (5) and in vivo rat brain (6) have reported a biexponential diffusion coefficient, suggesting the possibility of multiple compartments of water diffusion. Moreover the decreased diffusion that has been observed in the heart (3) could be a result of alterations in the relative size of these compartments, rather than a uniform reduction of water ADC in the affected region. This study was performed to determine if biexponential diffusion exists in the heart similar to that previously reported for neuronal tissue.