Abstract： Objective To explore the feasibility of quantitative hemodynamics measurement of inferior vena cava (IVC) in healthy volunteers with phase-contrast sequence on 3.0 T MR system (3.0 T PC-MRI),and to evaluate the relationship between IVC lumen area,blood flow,and velocity.Methods Fifty healthy adult volunteers prospective underwent IVC PC-MRI at 3.0 T MR system.All volunteers were from our hospital for the routine chest or abdomen examinations,no heart disease and lung disease always,heart rate,blood pressure,electrocardiogram was in normal range,no abnormalities were found in clinical and abdominal imaging examinations,and IVC disease was excluded by ultrasonic examination.The area (A),mean velocity (MV),mean flux (MF),regurgitant fraction (RF) and time-flow curve of upper and middle segments of IVC during one cardiac cycle were observed.Independent samples t test was used to compare IVC lumen area and blood flow,velocity between different genders,different age groups (18 to 30 years old group,more than 30 years old group) and different phase velocity encoding value of IVC middle segment,one-way ANOVA was used to compare different phase velocity encoding value of IVC upper segment [(60,80,100)cm/s].Pearson correlation coefficient and regression equation were used to evaluate the relationships between area,blood flow,and velocity.Results Among 50 patients with successful completion of the examination,significant difference was found in A,MV,MF and RF between the different IVC segments.MF of the IVC middle segment were (37.94 ± 7.32) and (33.68 ± 6.65) ml/s in male (n =24) and female (n =26),respectively ; significant difference was found in different genders (t =2.49,P =0.017).MF of upper segment and middle segments of IVC were (54.89 ± 10.98)and (38.29 ± 7.54)ml/s in 18 to 30 years old group(n =27),while MF of upper segment and the middle of IVC were (44.96 ± 8.49) and (32.65 ± 5.59) ml/s in older than 30 years old group (n =23) with significant difference(t =3.34,2.15,P ＜ 0.01).Peak positive velocity were (55.36 ± 6.30),(61.30 ± 12.42),(62.55 ± 13.09) cnm/s in different phase velocities (60,80 and 100 cm/s),while peak negative velocity (PNV) were (42.37 ± 19.18),(32.79 ± 24.67),(24.61 ± 21.20) cm/s with significant differences (F =4.258,7.794,P ＜ 0.05).The overall image quality was good for quantitative measurement between different phase velocity encoding values of upper segment and the middle IVC (image evaluation are greater than or equal to 3,11 patients were three points,24 patients were four points,15 patients five points).The relation between the PC flow image of IVC and the cardiac cycle was sine wave,the area and the velocity of upper and middle segments of IVC was negative (r =-0.466 and-0.765,P ＜ 0.01),and no linear correlation between the area and the flow of upper and middle segments of IVC (r =0.259,0.046,P ＞ 0.05).There were slight reverse flow during systolic and diastolic cycle.Conclusion The area,flow and velocity of IVC can be rapidly,accurately and noninvasive measured with PC-MRI,and different ages,different genders and different anatomical parts of IVC had obvious hemodynamic differences.