In Vivo Assessment of Rat Hearts with and without Myocardial Infarction by Cine NMR - Comparison of the NMR Method to Invasive Techniques and Application to Intervention Studies

Aim of the study was to test the feasibility of cine-NMR for assessment of the infarcted rat heart and to compare the results to established methods. Thereafter, the value of cine-NMR was tested in studies investigating interventions to change the course of the remodeling process. NMR was performed for determination of left ventricular (LV) volumes and mass, MI-size and cardiac output. After MRI rats underwent conventional hemodynamic measurements for determination of cardiac output and LV volumes by electromagnetic flowmeter and pressure-volume curves. LV wet weight was determined. MI-size was determined by histology. MRI-acquired MI-size (18.5±2%) was smaller than histology (22.8±2.5%, p<0.05) with close correlation (r=0.97). There was agreement in LV mass between MRI and wet weight (r=0.97, p<0.05) and in the MRI- and flowmeter measurements of cardiac output (r=0.80, p<0.05). Volume by MRI differed from pressure-volume curves with good correlation (r=0.96, p<0.05). In conclusion, cine-NMR is a valuable diagnostic tool applicable to the rat model of MI. Being non-invasive and exact it offers new insights in the remodeling process after MI because serial measurements are possible.