尿路小结石:MR和CT仿真内镜对比的实验研究

目的　探讨MR、CT仿真输尿管肾镜技术及其诊断尿路小结石的价值。方法　将 9枚直径 1～ 5mm的结石置入离体输尿管肾盂内 ,分别以生理盐水、3 %马根维显溶液或 3 %泛影葡胺完全充盈后行CT和MR容积扫描。源影像在工作站用Navigator软件做内镜重建。结果　VE对结石的敏感性源于CT技术者为 11.1%、源于多层薄层SS FSE序列者为44 .4%、源于HT2 FSE序列者 5 5 .6%、源于MR IVU序列者为 44 .4% ,检出的结石最小直径为 2mm。VE图像质量CT技术优于MR技术 (P <0 .0 1) ,MRH技术优于MR IVU技术 (P <0 .0 5 )。结论　磁共振仿真输尿管肾镜能够检出直径 2mm以上尿路结石 ,以HT2 FSE技术为佳 ;阳性造影剂法CT仿真内镜对尿路结石诊断价值有限

Small Urinary Calculi: An Ex-Vitro Study of CT and MR Virtual Endoscopy

Objective To detect the techniques of CT and MR virtual ureterorenoscopy and the value in diagnosis of small urinary calculi. Methods Nine calculi diameter from 1mm to 5mm after ureterolithotomy were pushed into the upper urinary tract of one ex vitro kidney which was given up transplanting. The virtual ureterorenoscopy was obtained by CT and MR urography data sets,and the urinary tract was distended respectively by meglumine diatrizoate(for helical CT urography,CTU), water(for MR urography,MRU) and gadolinium(for MR intravenous urography,MR IVU). MRU was performed with heavily T 2 weighted fast spin echo(HT 2 FSE) and thin slice single shot fast spin echo(SS FSE).MR IVU was performed with 3D/2D fast SPGR. Results The sensitivity of MR virtual ureterorenoscopy reconstructed by source images of SS FSE, HT 2 FSE and MR IVU was 44.4%, 55.6% and 44.4% respectively.The smallest calculi was 2mm in diameter. The sensitivity of CT virtual ureterorenoscopy was only 11.1%. The quality of virtual ureterorenoscopy from CT data sets was better than that of from MR data sets ( P <0.01),and MRU techniques was superior to MR IVU techniques ( P <0.05). Conclusion MR virtual ureterorenoscopy could detect urinary calculi more than 2mm in diameter, of which the best techniques is MRH with HT 2 FSE sequences.It is limited for positive contrast medium insufflated CT virtual endoscopy to diagnose urinary calculi.