中文摘要：

目的: 在猪为心肌的梗塞(MI ) 变化调查在并行的发行量和提高对比的先生信号之间的关系。

英文摘要：

Aim： To investigate the relationship between the collateral circulation and contrast-enhanced MR signal change for myocardial infarction （MI） in pigs. Methods： Pigs underwent permanent ligation of two diagonal branches of the left anterior descending artery. First-pass perfusion （FPP） MRI （for detecting myocardial perfusion abnormalities） and delayed enhancement （DE） MRI （for estimating myocardial infarction） using Gd-DTPA were performed at 2 h, 7 d and 4 weeks after the coronary occlusion. Myocardial blood flow （MBF） was evaluated using nonradioactive red-colored microspheres. Histological examination was performed to characterize the infarcts. Results： Acute MI performed at 2 h afterwards was characterized by hypoenhancement in both FPP- and DE-MRI, with small and almost unchanged FPP-signal intensity （SI） and DE-SI due to negligible MBF. Subacute MI detected 7 d afterwards showed small but significantly increaseing FPP-Sl, and was visible as a sluggish hyperenhancement in DE-MRI with considerably higher DE-SI compared to the normal myocardium; the MBF approached the half-normal value. Chronic MI detected at 4 weeks afterwards showed increasing FPP-SI comparable to the normal myocardium, and a rapid hyperenhancement in DE-MRI with even higher DE-SI; the MBF was close to the normal value. The MBF was correlated with FPP-Sl （r=＋0.94, P〈0.01） and with the peak DE-Sl （r=＋0.92, P〈0.01） at the three MI stages. Remodeled vessels were observed at intra-infarction and peri-infarction zones during the subacute and chronic periods. Conclusion： Progressive collateral recovery determines the characteristic profiles of contrast-enhanced MRI in acute, subacute and chronic myocardial infarction in pigs. The FPP- and DE-MRI signal profiles not only depend on the loss of tissue viability and enlarged interstitial space, but also on establishing a collateral circulation.