Objective To explore the distribution of the liquid food in the stomach of patients with postprandial distress syndrome (PDS)-predominated functional dyspepsia (FD)and the mechanism of its gastric dynamic dysfunction.Methods Fifty-two patients with PDS and 18 healthy volunteers underwent gastric emptying examination with ultrasound scanner provided.The proximal and distal gastric area and volume,area and volume ratio of proximal and distal gastric as well as emptying rate of proximal and distal gastric were calculated at fasting,maximum satiety,30 min,60 min,90 min and 120 min after meal. Student′s t test andχ2 test were performed for statistical analysis.Results Proximal gastric volume of PDS group at the time of fasting and 120 min after meal were (9.06±7.88)and (24.72±24.02)cm3 ,which were larger than those of healthy control group ((5 .96 ± 2.13 )cm3 ,(19.48 ± 12.32 )cm3 ),and the differences were statistically significant (t=-1 .637 and -0.875 ,both P <0.05).Ratio of proximal and distal gastric area at maximum satiety in PDS group was 1 .63±0.42 and that in healthy control group was 2.33±0.63,and the difference was statistically significant (t =5 .044,P <0.05 ).Ratio of proximal and
distal gastric volume in PDS group and healthy group at fasting was 0.60 ± 0.38 and 0.46 ± 0.19, respectively,that at maximum satiety was in PDS group and healthy group 0.91 ±0.27,1 .30 ±0.48, respectively,and the differences were statistically significant (t = - 1 .505 and 3.970,both P <0.05). The emptying rates of proximal stomach of PDS group at 30 min and 90 min postprandial were (28.10 ± 25 .03)% and (68.80±16.14)%,respectively,those of healthy control group were (34.97 ±14.41 )%and (75 .86 ±9.86)%,and the differences were statistically significant (t =1 .087 and 1 .718,both P <0.05).There was no statistically significant difference in emptying rate of distal stomach between two groups (all P > 0.05 ).Conclusions The volume of distal stomach was larger than that of proximal stomach in PDS patients at maximum satiety in liquid food distribution,which may be the cause of decreasing emptying rate of proximal stomach.And proximal stomach dominated gastric motility in PDS patients.