MAGNETIC-RESONANCE-IMAGING ACCURATELY ESTIMATES LV MASS IN A TRANSGENIC MOUSE MODEL OF CARDIAC-HYPERTROPHY

Transgenic mice with a dysfunctional guanylyl cyclase A gene (GCA -/-) are unable to transduce the signals from atrial naturetic peptide and develop hypertension and cardiac hypertrophy Magnetic resonance imagi ng (MRI) was performed to assess cardiac hypertrophy in these animals, using wild-type siblings as controls. Anesthetized mice were studied by gated multislice, multiphase cine MRI at 1.5 T. Simpson's rule was used to estimate left ventricle (LV) mass and volumes from short-axis images. Correlation between LV mass evaluated by MRI and at necropsy w as excellent, with LVnecropsy = 1.04 x LVMRI + 4.69 mg (r(2) = 0.95). By MRI, GCA -/- LV mass was significantly different when compared with isogenic controls [GCA -/-, 226 +/- 43 mg (n = 14) vs. controls, 156 +/- 14 mg (n = 10); P < 0.0001]. LV volumes and ejection fraction in t he two groups were not significantly different. MRI provides an accura te means for the noninvasive assessment of murine cardiac phenotype an d may be useful in following the effects of genetic modification.