Objective To determine the gastric emptyingtime for liquids in the healthy volunteers by magnetic resonance imaging (MRI) and to provide a reference for reasonable preoperative fastingtime.Methods Nineteen healthy volunteers of both sexes,of ASA physical status Ⅰ or Ⅱ,aged 20-60 yr,were enrolled in the study.The volunteers were fasted from the intake of liquids or solids starting from 2200 the night before the trial,and 12.5% carbohydratesolution 400 ml containing 40 g maltodextrin and 10 g sucrose was given orally.MRI was performed to measure the baseline gastric fluid volume at 800 on the day of the trial (T0).The gastric fluid volume was measured immediately after administration of the oral solution,and then measured every 25 min until the gastric fluid volume was returned to the baseline before administration of the oral solution or to <25 ml,and was recorded as T25,T50,T75,T100,et al.The gastric fluid volume was drawn using a computer to obtain the curve for gastric emptying.The gastric half and total emptying time was calculated using the curves.Results The gastric half emptying time was (32± 12) min,and the gastric total emptying time was (99±22) min in the volunteers.Compared with those at Tb,the gastric fluid volume was significantly increased at T25,T50,T75,T100,and no significant change was found in gastric fluid volume at T125,T150and T175.Conclusion After oral intake of liquids,the gastric emptyingtime is about 2 h,indicating that the preoperative fastingtime for liquids can be shortened to 2 h before anesthesia in the healthy volunteers.