Objective To investigate the treatment effect of retrograde holmium laser lithotripsy on treatment of impacted ureteral calculi.Methods One hundred and twenty-eight patients with ureteral calculi in the Second Affiliated Hospital of Xinjiang Medical University from Feb.2011 to Dec.2013 were divided into unimpacted ureteral calculi group (70 cases) and impacted ureteral calculi (58case).The treatment efficacy,operation complications of holmium laser lithotripsy and the causes of the failure of operation were recorded.Results The stone clearance rate,operative periods and postoperative incidence of gross hematuria in the un-impaction group were 91.4％ (64/70),(36.3 ± 10.7) min and 51.4％ (36/70) respectively,significant different from those in impacted ureteral calculi(74.1％ (43/58),(45.2 ± 13.9) min and 84.5％ (49/58) respectively;x2 =6.914,t =3.736,x2 =15.535 ;P ＜ 0.05).There were no significant difference between the un-impaction group and impaction group in terms of the postoperative hospital stay periods,analgesics utilization rate,urinary tract infection rates and ureteral perforation rate.In the un-impaction group,6 cases were surgical failure due to the movement of ureteral calculi during the operation.Fifteen cases were surgical failure in the impaction group,mainly due to the stone fragments move,the ureter excessive distortion and ureteral stricture.The success rate was 58.3％ (14/24) of the stones,which were above the level of L4 in the impaction group,while the success rate was 85.3％ (29/34) of the stones that was below the level of L4 in the impaction group (x2 =5.334,P ＜ 0.05).Conclusion Impacted ureteral calculi is more difficult to deal than unimpacted stone.The operation success rate of impacted stones above the level of L4 is less than below L4 due to stone fragments and ureter distorting.

Objective To study the application value of iodixanol in gemstone spectral imaging with low CT dosage.Methods Forty hundred and twenty -six cancer patients with normal kidney function were selected .All of them underwent enhanced gemstone spectral CT scan with low dosage .They were individed into two groups with random number table,including observation group(n=213) and control group(n=213).The observation group was injected isotonic iodixanol ( 270 mgI/mL ) intravenously , while the control group was injected hypertronic iohexol (350mgI/mL) intravenously.With the same injection speed,the acute adverse reaction within 1h and delayed adverse reaction between 1h～7d were recorded.Meanwhile,the changes of Scr and Ccr ,the occurrence rate of contrast -induced nephropathy(CIN) and short -term prognosis were also recorded.Results Fifty-three patients occurred acute adverse reaction,among them 18 cases(8.45％) were in the observation group,35 cases(16.43％) were in the control group,there was statistically significant difference between the two groups (χ2 =10.791,P<0.05).Three patients(1.50％) of the control group occurred delayed adverse reaction ,no one was in the observation group .The adverse reaction disappeared after some time .Two kinds of contrast media caused slight increase of Scr and decrease of Ccr,but there were no statistically significant differences between them (all P>0.05).Conclusion The intrave-nous injection of iodixanol can reduce the occurrence of acute adverse reaction ,will not increase the incidence of CIN . It can be used safely .