Direct histological validation of diffusion tensor MRI in formaldehyde- fixed myocardium

Diffusion tensor MRI is emerging as a rapid, nondestructive method to map myocardial fiber organization. It accurately measures myofiber orientation in hearts bathed in or perfused with cardioplegic solution. This study shows it also accurately maps the fibrous architecture of formalin- fixed hearts. Fiber orientations obtained by MRI and histology at the same locations in an excised portion of rabbit ventricle differed on average by 3.7°(SD = 6.4°, N = 70), a closer correspondence than achieved with previous preparations. The longer acquisition times afforded by fixed-heart imaging provides better accuracy, and should enable high-resolution reconstruction of the entire ventricular architecture. (C) 2000 Wiley-Liss, Inc.