不同管电压CT扫描鉴别尿酸与非尿酸泌尿系结石的对比研究

The study of conventional CT scan with different tube voltages to distinguish uric acid and non-uric acid urinary calculus

目的探讨不同管电压的常规CT扫描参数鉴别尿酸与非尿酸泌尿系结石的可行性,并筛选鉴别两者的最优管电压。方法选择本院2018年9月至2021年1月收治的160例泌尿系结石患者为研究对象,所有患者均行泌尿系CT平扫检查且按不同的管电压随机分为A、B、C三组,其中A组(63例)采用120 kV,B组(47例)采用100 kV,C组(50例)采用80 kV。比较三组患者的有效剂量(ED)与CT图像评分、剂量长度乘积(DLP)以及CT容积剂量指数(CTDIvol)。比较三组患者的尿酸与非尿酸结石平均CT值(HUm)与CT值标准差(HUsd)的差异,并且运用受试者工作特征(ROC)曲线评价三组HUm与HUsd鉴别泌尿系结石成分的诊断效能。结果三组患者的尿酸结石的HUm、HUsd均低于非尿酸结石,差异均具有统计学意义(均P<0.01)。三组的HUm、HUsd鉴别尿酸与非尿酸结石的ROC曲线下面积分别为:A组(0.811、0.897)、B组(0.815、0.932)、C组(0.728、0.842),扫描条件为100 kV时,泌尿系结石的HUsd诊断尿酸与非尿酸结石效能最佳。A组患者的CTDIvol、DLP、ED高于B、C组,B组高于C组,差异均有统计学意义(均P<0.001),三组患者的HUm、HUsd比较,差异均无统计学意义(均P>0.05)。三组患者的CT图像评分比较,差异无统计学意义(H=0.57,P>0.05)。结论管电压在100 kV条件下鉴别尿酸与非尿酸结石的诊断效能最佳,且可有效降低患者接受的辐射剂量。

Objective To explore the feasibility of differential diagnosis of uric acid and non-uric acid urinary calculus by conventional CT scanning parameters with different tube voltages,and to screen the optimal tube voltage for differential diagnosis of uric acid and non-uric acid urinary calculus.Methods From September 2018 to January 2021,160 patients with urinary calculi in our hospital were randomly divided into three groups for CT scan,group A(63 cases)with 120 kV,group B(47 cases)with 100 kV,and group C(50 cases)with 80 kV.The effective dose(ED),CT score,dose length product(DLP)and volume CT dose index(CTDIvol)of the three groups were compared.Differences in mean CT value(HUm)and standard deviation of CT value(HUsd)of uric acid and non-uric acid calculus were compared among the three groups.The diagnostic efficiency of HUm and HUsd in differentiating urinary calculus was evaluated by using a receiver operating characteristic curve(ROC).Results The HUm and HUsd of uric acid stones in the three groups were lower than those of non-uric acid stones,and the differences were statistically significant(all P<0.01).The area under the ROC of HUm and HUsd in identifying uric acid and non-uric acid calculus in the three groups were follow as:group A(0.811,0.897),group B(0.815,0.932),and group C(0.728,0.842),respectively.When the scanning condition was 100 kV,HUsd had the best performance in diagnosing uric acid and non-uric acid stones.The CTDIvol,DLP and ED of group A were higher than those of group B and C,and those of group B were higher than those of group C,and the differences were statistically significant(all P<0.001).There was no significant difference in HUm and HUsd among the three groups(all P>0.05).There was no significant difference in CT score among the three groups(H=0.57,P>0.05).Conclusions The tube voltage under 100 kV has the best diagnostic performance in differentiating uric acid from non-uric acid stones,and can effectively reduce the radiation dose received by patients.