结石近心端与远心端输尿管直径比值对输尿管中上段嵌顿性结石的预测价值

Predictive value of proximal and distal ureteral diameter ratio for impacted stones in the middle and upper ureter

目的探讨结石近心端输尿管直径(D1)与远心端输尿管直径(D2)的比值(DDR)对输尿管中上段嵌顿性结石的预测价值。方法回顾性分析山西医科大学第三医院2014年1月至2021年11月收治的173例输尿管中上段结石患者的临床资料。男75例, 女98例;年龄中位值56.0(51.0, 62.0)岁;体质量指数中位值26.1(24.8, 27.2)kg/m^(2)。分析患者影像资料。嵌顿性结石定义为行静脉尿路造影(IVU)或CT尿路造影检查(CTU)时, 造影剂不能通过梗阻部位导致梗阻部位以下部分输尿管不能正常显影。D1定义为水平位CT图像肾下极水平输尿管直径;D2定义为距结石3cm处远心端输尿管直径。比较嵌顿性结石与非嵌顿性结石患者的结石直径、结石CT值、D1、D2、DDR等。对有差异的指标采用单因素logistic回归分析;采用随机数字表法将所有结石患者按7∶3比例分为训练集和验证集, 通过最小绝对收缩和选择算子(LASSO)回归分析, 得出独立影响因素并建立列线图模型(模型1)。采用受试者工作特征(ROC)曲线和曲线下面积(AUC)对模型的预测效能进行验证, 通过逐步法多因素logistic回归构建其他3个有效模型(模型2~4)。采用deLong检验, 比较模型1与另外3个模型ROC曲线的AUC差异。通过临床决策曲线(DCA)分析模型1中患者净获益情况。结果本研究中64例(37.0%)为嵌顿性输尿管结石, 109例(63.0%)为非嵌顿性输尿管结石。嵌顿性输尿管结石与非嵌顿性输尿管结石患者的结石直径[7.8(6.2, 8.8)mm与6.3(5.2, 8.1)mm]、结石CT值[878.5(763.8, 940.5)HU与764.0(613.0, 854.0)HU]、D1[11.1(8.9, 14.9)mm与9.1(7.1, 10.8) mm]、D2[4.1(3.1, 4.9) mm与5.0(4.1, 5.9) mm]和DDR[3.1(2.3, 3.9)与1.8(1.4, 2.4)]差异均有统计学意义(P<0.05)。单因素logistic回归分析结果显示结石直径(OR=1.333, P<0.001)、结石CT值(OR=1.002, P=0.002)、D1(OR=1.146, P<0.001)、D2(OR=0.652, P<0.001)和DDR(OR=2.995, P<0.001)均是嵌顿性结石的影响因素。训练集与验证集分别包括122例和51例, 其结石影像特征及结石嵌顿比例[64.1%(41/122)与35.9%(23/51)]差异均无统计学意义(P>0.05)。LASSO回归分析结果示, 最优范围内的最简结果对应的λ为0.0908, 此时纳入的变量为3个, 筛选出嵌顿性结石的影响因素为结石直径(系数为0.0700, OR=1.073)、结石CT值(系数为0.0003, OR=1.001)和DDR(系数为0.5960, OR=1.815), 并建立模型1。根据模型拟合结果绘制ROC曲线, 模型1的AUC为0.862, 模型2~4的AUC分别为0.859、0.762、0.793。deLong检验结果示, 模型1与模型2的AUC差异无统计学意义(Z=0.248, P=0.804), 模型1的AUC优于模型3(Z=2.888, P=0.004)和模型4(Z=2.321, P=0.020)。DCA提示模型1最高可提高约21%的患者净获益率。结论 DDR是输尿管嵌顿性结石的影响因素, 且采用DDR、结石CT值及结石直径构建的预测模型能有效预测输尿管中上段嵌顿性结石的发生概率。

Objective To evaluate the predictive value of proximal ureteral diameter(D1)to distal ureteral diameter(D2)ratio(DDR)for impacted stones in the middle and upper ureter.Methods The clinical data of 173 patients with middle and upper ureteral calculi admitted to the Third Hospital of Shanxi Medical University from January 2014 to November 2021 were retrospectively analyzed.There were 75 males and 98 females,with the median age of 56.0(51.0,62.0)years old and median body mass index of 26.1(24.8,27.2)kg/m^(2).The imaging data of the patients were analyzed.The impacted stones were defined as the inability of the contrast agent to pass through the site of obstruction when intravenous urography or CT urography was performed,resulting in the inability of the ureter to visualize normally in parts below the site of obstruction.D1 was defined as the proximal ureteral diameter at the lower pole of the kidney on horizontal CT images.D2 was defined as the ureteral diameter 3 cm from the calculi.The stone diameter,stone CT value,D1,D2,and DDR were compared between impacted stone group and non-impacted stone group.Univariate logistic regression analysis was used to analyze the different indicators.Random number table was used to divide the training set and validation set according to the ratio of 7:3.Through least absolute shrinkage and selection operator(LASSO)regression analysis,the independent influencing factors were obtained and the nomogram model was established(Model 1).Receiver operating characteristic(ROC)curve and area under the curve(AUC)were used to verify the predictive efficacy of the model,and the other three effective models(Model 2-4)were constructed by stepwise multivariate logistic regression.The deLong test was used to compare whether there was a significant difference in the AUC between Model 1 and the other three models,and the net benefit of patients was analyzed by clinical decision curve analysis(DCA).Results In this study,64 cases(37.0%)were impacted ureteral calculi and 109 cases(63.0%)were non-impacted ureteral calculi,and there were significant differences in diameter[7.8(6.2,8.8)mm vs.6.3(5.2,8.1)mm],CT value[878.5(763.8,940.5)HU vs.764.0(613.0,854.0)HU],D1[11.1(8.9,14.9)mm vs.9.1(7.1,10.8)mm],D2[4.1(3.1,4.9)mm vs.5.0(4.1,5.9)mm]and DDR[3.1(2.3,3.9)vs.1.8(1.4,2.4)]between the two groups(P<0.05).The results of univariate logistic regression analysis showed that stone diameter(OR=1.333,P<0.001),CT value(0R=1.002,P=0.002),D1(OR=1.146,P<0.001),D2(OR=0.652,P<0.001)and DDR(OR=2.995,P<0.001)were the influencing factors of impacted stones.The training set and validation set included 122 cases and 51 cases,respectively,without significant differences in their image characteristics and outcomes(P>0.05).The results of LASSO regression analysis showed that corresponding to the simplest result in the optimal range was 0.0908,and three variables were included at this time,and the influencing factors of impacted stones were stone diameter(coefficient 0.0700,OR=1.073),CT value(coefficient 0.0003,OR=1.001)and DDR(coefficient 0.5960,OR=1.815).Moreover,Model 1 was established.According to the model fitting results,ROC curves were plotted,and the AUC of Model 1 was 0.862,and the AUCs of Model 2-4 were 0.859,0.762,and 0.793,respectively.After deLong test,there was no significant difference between Model 1 and Model 2(Z=0.248,P=0.804).The AUC of Model 1 was superior to that of Model 3(Z=2.888,P=0.004)and Model 4(Z=2.321,P=0.020).The DCA suggested that Model 1 could improve the net benefit rate by up to approximately 21%of patients.Conclusions DDR is the influencing factor of impacted ureteral calculi,and the model constructed by DDR,stone CT value and stone diameter can effectively predict the probability of impacted ureteral calculi in the middle and upper ureter.