The Feasibility Study Of Non-contrast-enhanced MR Venography Using Fresh Blood Imaging For Iliac-femoral Vein

Purpose:To investigate the feasibility of non-contrast-enhanced MR venography using Fresh Blood Imaging for iliac-femoral vein by comparing acquisition using different PE directions and by comparing acquisition in supine and prone position. Material and method:Thirty-five young healthy volunteers were enrolled in this study and were examined by non-contrast enhanced MR venography using Fresh Blood Imaging in 1.5T MR scanner. There were 14 men and 21 women; mean age 26.31±1.91 years, with a range from 22~30. Each volunteer was imaged in the supine first with the PE direction setting perpendicular to vessel orientation(Right to left, R-L) and parallel to vessel orientation(Head to foot, H-F) successively. Then the volunteers were imaged in the prone position with the same PE direction as in the supine position. All the raw data are post-processed into coronal maximum-intensity-projection(MIP) images. The venous system was divided into 6 segments; left and right common femoral vein(CFV), external iliac vein(EIV) and common iliac vein(CIV). The venous visualization score(VVS) and arterial contamination score(ACS) were rated on a five and three point scale respectively. The mean VVS and ACS were calculated. Mean differences in VVS and ACS between images of the R-L and H-F PE direction in both positions and mean differences in VVS and ACS between images of the supine and prone position in the H-F PE direction were statistically compared using the Wilcoxon signed rank test separately for the all segments. Results:All volunteers were well tolerated and all MR data sets were eligible for evaluation. The VCS was significantly higher using H-F PE direction than using R-L PE direction(P<0.05) in both positions. CFV revealed a significantly higher score in VCS in the prone position as compared to the supine position(P<0.05). No significant difference in VCS of EIV and CIV was observed after alteration in scan position. In FBI venography, the EIV got the highest average VCS among the three major segments, with CFV took the second place and CIV the lowest in both positions. FBI gave arterial contamination in both PE directions and both scan positions. The H-F PE direction gave more arterial contamination than R-L PE direction. Conclusion:The H-F PE direction provides less flow-void in iliac-femoral veins than the R-L direction. FBI provides better visualization of the CFV in prone position compare to supine position but no significant visualization difference for EIV and CIV were observed after position alteration. Non contrast enhanced FBI can provide good visualization in EIV, but deteriorated visualization at CFV and CIV using FBI venography and undesirable arterial contamination illustrates that FBI for iliac-femoral veins still needs further studies.