Comparison Of Diagnostic Values In Ureteral Stones With Two Methods Of 64-slice CT Urography

Objective To compare the diagnostic values of ureteral stones with two methods of 64-slice computed tomographic urography(CTU);to explore the feasibility of speculating on the delayed CT scan time with the thickness of renal parenchyma and the caliber of ureter.Materials and methods Two groups were included:Contrasted group(Group A),36 patients who were diagnosed to ureteral stones by B ultrasound,underwent IVP and later or delayed CTU;Non-contrasted group(Group B),23 patients with renal colic and suspection of ureteral stone,underwent emergency plain CT.The data of all the patients were transferred to workstation for 3D reconstruction of multiple plane reconstruction (MPR)and curve plane reformation(CPR).x~2 test was used with the statistic software of SPSS 12.0,to compare the diagnostic accuracy for ureteral stones between the methods of KUB+IVP and CTU of Group A,CTU of Group B and B-Ultrasound,CTUs of Group A and B.As to the delayed visualization of urinary tracts in Group A,the average values of renal parenchymal thickness and ureteral diameter were measured,and their relationship with the delayed time of visualization was studied.Result(1)In Group A,20(20/36)cases of ureteral stone were confirmed by KUB+IVP,16 (16/36)by CTU.Between them,there was significant difference(x~2 =8.13,p＜0.05).(2)In Group B,22(22/23)and 15(15/23)cases of ureteral stones were diagnosed by CTU and B ultrasound,respectively,with significant difference(x~2=4.97,p＜0.05).(3)There was no significant difference between CTUs of Group A and B for diagnostic accuracy of ureteral stones(x~2=0.55,p＞0.05).(4)In Group A,ureteral visualization was delayed gradually along with the decrease of renal parenchemal thickness and the increase of ureteral diameter. When the mean thickness of renal parenchyma decreased below 0.99mm,or when the mean diameter of ureter increased to 17mm,ureter was not visualized.Conclusion(1)CTUs of Group A and B were superior to B ultrasound and KUB+IVP for accuracy of diagnosing ureteral stones;(2)There is no statistical difference between CTUs of Group A and B in the accuracy of diagnosing ureteral stones;CTU of Group B,with advantages of convenience,non-contrast media,is especially suited for checkup of patients with renal colic.(3)The mean values of renal parenchymal thickness and ureteral diameter can be regarded as a promising index for speculating the ideal delay-time point of CTU.