CARDIAC MRI OF THE NORMAL AND HYPERTROPHIED MOUSE HEART

With the development of recent transgenic techniques, studies involvin g mice offer opportunities to increase understanding of cardiac diseas e. This provides motivation for the current study to perform noninvasi ve evaluation of the normal and hypertrophied mouse heart with MRI. By acquiring ECG and respiratory signals, the MR image acquisition was g ated to both the cardiac and respiratory cycles. Combining a spin-warp imaging sequence with an RF surface coil resulted in short-axis image s that allowed quantification of in vivo cardiac mass. Excellent agree ment between MRI-determined (y) and postmortem heart weight (x) was ob tained: y = 0.991x + 1.43 (r = 0.996). Isoproterenol, at 282 mu mol/kg body weight (BW) and 573 mu mol/kg BW, induced a dose-dependent incre ase in the ratio of heart weight to BW of 16.8 +/- 1.09% and 24.1 +/- 1.71%, respectively, which was accurately measured by MRI. These resul ts demonstrate the ability of MRI to noninvasively monitor cardiac ana tomy in the mouse.