Quantitative assessment of infarct size in vivo by myocardial contrast echocardiography in a murine acute myocardial infarction model.
BACKGROUND
In vivo measurement of the infarct size in a small animal model is still challenging. The purpose of this study was to evaluate the feasibility of quantitative assessment of infarct size by myocardial contrast echocardiography (MCE) in the acute myocardial infarction (AMI) model of the rat.


METHODS
In 32 Sprague-Dawley rats with AMI, we measured total myocardial area (TMA) and infarct area (IA) of the rats by MCE study (MCE method). They were compared with those of postmortem heart measured by planimetry after histochemical staining with triphenyl tetrazolium chloride solution (TTC method). Simple TTC staining was done in 13 rats (Group 1). To reduce the postmortem change, continuous aortic and left ventricular (LV) pressure was loaded during TTC staining in 19 rats (Group 2).


RESULTS
The TMA, IA, and IA/TMA ratio measured by the MCE method were 38.4+/-3.4 mm2, 18.3+/-0.8 mm2, and 0.37+/-0.02 in Group 1, and 43.7+/-1.8 mm2, 15.8+/-1.1 mm2, and 0.37+/-0.02 Group 2, respectively. Those measured by the TTC method were 66.1+/-2.2 mm2, 29.3+/-1.1 mm2, and 0.44+/-0.01 in Group 1, and 65.9+/-2.5 mm2, 26.5+/-1.7 mm2, and 0.40+/-0.02 in Group 2, and 65.9+/-2.5 mm2, 26.5+/-1.7 mm2, and 0.44+/-0.02 in Group 2, respectively. Compared with the TTC method, the MCE method underestimated the TMA and IA in both groups (p<0.001). There was no difference in TMA and IA between the two groups in both methods. IA/TMA ratio showed significant correlation between the two methods in both groups (r=0.85, p<0.001).


CONCLUSIONS
The IA/TMA ratio measured by the MCE method may be useful for in vivo estimation of the myocardial infarct size in the AMI model of the rat.
Park
Seung Woo
SW
Samsung Medical Center, Department of Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, No. 50 Ilwon-Dong, 135710, Kangnam, Seoul, Republic of Korea. swpark@smc.samsung.co.kr
Lee
Sung Yun
SY
Park
Sun Jin
SJ
Lee
Sang-Chol
SC
Gwon
Hyeon-Cheol
HC
Kim
Duk-Kyung
DK
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods; D006321:Heart / Q000503:physiopathology*; D007275:Injections, Intravenous; D009203:Myocardial Infarction / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003287:Contrast Media