Objective To compare the effects of different doses of adenosine(AD)on the left coronary blood flow(CBF)and left coronary flow reserve(CFR)in mini-swine.Methods By using Doppler flow wire and intracoronary ultrasound imaging catheter at the middle segment of LAD,coronary average peak flow velocity(APV)and lumen area were measured in 10 healthy mini-swines.CBF was calculated from the equation of 0.6 APV times 0.5 lumen area.Intracoronary bolus injection of different dose AD(12μg,18μg,24 μg and 36μg,separately)was used to induce maximal coronary hyperemic reaction.CFR was defined as the ratio of hyperemic CBF to resting CBF.Results Intracoronary bolus injection of 18μg AD level induced a maximal coronary vasodilation.Significant difference in the hyperemic CBF existed between 12 μg AD dose and 24μg or 36μg AD dose(P＜0.05).No significant difference in heart rate,blood pressure,rCBF and CFR was found among three different AD dose groups(18μg,24μg,and 36μg).Conclusion CBF and CFR in mini-swine can be effectively assessed by bolus injection of AD with the dose of(18～24)μg.