Abstract P35: Real-time Myocardial Contrast Echocardiography in Rat: Infusion vs. Bolus Administration

Abstract

AIM: To compare the feasibility of real-time myocardial contrast echocardiography (RTMCE) in rats with infusion and bolus administration of BR1. Methods: RTMCE was performed in 12 Sprague-Dawley rats using B-mode RTMCE following the BR1 infusion or bolus injection. The myocardium signal intensity (SI) was plotted against time and was fitted to exponential functions. The plateau SI (A) and rate of SI increase (â) for the infusion study and peak signal intensity (PSI) for the bolus study were obtained. 99m Tc-Sestamibi and Evans blue were used to assess myocardial blood perfusion and to calculate the myocardium perfusion defect area ex vivo . Results: High-quality RTMCE images were successfully obtained using each method. At baseline, all LV segments showed even contrast distribution (Figure A ). Following left anterior descending (LAD) aorta ligation, significant perfusion defect was observed in LAD beds (Figure B , arrows) with a significantly decreased A*â and PSI values compared to LCx beds (Infusion: A* â LAD : 5.42 ± 1.57dB, A* â LCx : 46.52 ± 5.32dB, p± 0.05; Bolus: PSI LAD : 2.11 ± 0.67dB, PSI LCx : 20.68 ± 0.72 dB, p<0.05), which was consistent with 99m Tc-Sestamibi distribution findings. Myocardial perfusion defect areas assessed by both methods showed no differences and showed good correlation with Evans blue staining. ED frames were more favorable for imaging analysis. Conclusions: Both infusion and bolus administration of the contrast agent combined with RTMCE technique can provide a reliable and non-invasive approaches for myocardial perfusion assessment in rats, and the infusion method was more suitable for quantitative analysis of myocardial blood flow.