Usefulness of intravenous myocardial contrast echocardiography in rats

OBJECTIVES: Few intravenous myocardial contrast echocardiography trials have evaluated myocardial perfusion in small animals. The feasibility of using intravenous myocardial contrast echocardiography to assess the ischemic area in rats was investigated. METHODS: Fourteen open chest Wister male rats were examined. Intravenous myocardial contrast echocardiography was performed by fundamental and intermittent mode using a high frequency (5-12 MHz) transducer (SONOS 5500) with injection of NC100100 (20% dilution) into the femoral vein. The mechanical index was set to 1.6. Baseline-subtracted video intensity (256 level) was measured in the anterior, posterior, septal and lateral walls of the left ventricle. The left anterior descending artery was ligated in 16 rats. The area at risk was evaluated by myocardial contrast echocardiography and compared to the area of defect by Evans Blue staining. RESULTS: All wall segments were clearly opacified (anterior 63.8 +/- 24.7, posterior 27.0 +/- 11.0, septal 44.5 +/- 11.6, lateral 52.3 +/- 19.1), although the baseline-subtracted video intensity of the posterior wall was low. The area at risk was clearly observed, and there was a good correlation with the nonperfused area by Evans Blue staining (y = 1.13x-3.54, r = 0.98). CONCLUSIONS: Intravenous myocardial contrast echocardiography can detect the perfusion defect even in rats using a high frequency transducer and suitable setup of equipment.