目的·探究利尿肾动态显像中20分钟残留率（20-minute residual rate，R₂₀）等参数对于先天性单侧肾盂输尿管连接部梗阻（ureteropelvic junction obstruction，UPJO）患儿肾盂成形术手术时机的预测价值。方法·回顾性分析2018年8月到2023年8月期间在上海交通大学医学院附属新华医院核医学科初次就诊的110例先天性单侧UPJO患儿的临床资料和利尿肾动态显像结果。随访患儿初次行利尿肾动态显像后的影像检查结果和肾积水进展情况。以患儿是否因肾积水进展行肾盂成形术为结局事件，将患儿分为手术组和非手术组。比较2组患儿年龄、性别、肾积水侧别，以及基线利尿肾动态显像参数包括肾血流灌注率（blood perfusion rate，BPR）、分肾功能（differential renal function，DRF）、达峰时间（time to peak，T_max）、半排时间（time to half，T_1/2）及R₂₀。采用Logistic回归分析各参数对肾积水进展的影响。采用受试者操作特征（receiver operating characteristic，ROC）曲线分析利尿肾动态显像参数对患儿是否需要手术干预的预测价值。采用Wilcoxon检验比较行2次利尿肾动态显像患儿的检查参数。结果·在随访过程中有60例患儿因肾积水进展行肾盂成形术，50例患儿肾积水未进展。手术组与非手术组患儿基线状态DRF、T_max、T_1/2和R₂₀的差异均有统计学意义（均P<0.05）。单因素和多因素Logistic回归分析显示，R₂₀是肾盂成形术的独立预测因素（OR=4.730，95% CI 1.009~1.178，P=0.030）。R₂₀预测肾盂成形术的灵敏度为88.3%，特异度为56%，ROC曲线下面积为0.758（95% CI 0.667~0.850，P=0.000），临界值为90.08%。38例患儿在随访过程中进行了第二次利尿肾动态显像，DRF较前下降，2次DRF的差异有统计学意义（Z=-2.589，P=0.010），尤其是R₂₀≥90.08%的患儿（Z=-2.166，P=0.030）。非手术组患儿R₂₀较基线明显下降（Z=-2.062，P=0.039），而手术组患者R₂₀较基线增加，但差异无统计学意义（P>0.05）。结论·R₂₀对于先天性单侧UPJO患儿肾盂成形术的预测具有重要意义。对于R₂₀≥90.08%的患儿，应尽早行肾盂成形术，以防止肾功能进一步恶化。

Objective ·To explore the predictive value of diuretic renal scintigraphy parameters such as 20-minute residual rate (R₂₀) for pyeloplasty in children with congenital unilateral ureteropelvic junction obstruction (UPJO). Methods ·The clinical data and diuretic renal scintigraphy results of 110 children with congenital unilateral UPJO who were first treated at the Department of Nuclear Medicine, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine from August 2018 to August 2023 were retrospectively analyzed. The imaging results and the progress of hydronephrosis were followed up after the first diuretic renal scintigraphy. According to the outcome event of pyeloplasty due to the progression of hydronephrosis, the children were divided into operation group and non-operation group. Age, gender, side of hydronephrosis, and baseline diuretic renal scintigraphy parameters including blood perfusion rate (BPR), differential renal function (DRF), time to peak (T_max), time to half (T_1/2) and R₂₀ were compared between the two groups. Logistic regression was used to analyze the effect of various parameters on the progression of hydronephrosis. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of diuretic renal scintigraphy parameters for surgical intervention. Wilcoxon test was used to compare the examination parameters of two diuretic renal dynamic imaging. Results ·During the follow-up, 60 children underwent pyeloplasty after progression, and the other 50 children did not progress. The differences in DRF, T_max, T_1/2 and R₂₀ between the two groups of children at baseline were statistically significant (all P<0.05). Univariate and multivariate Logistic regression analysis showed that only R₂₀ was an independent predictor of pyeloplasty (OR=4.730, 95%CI 1.009-1.178, P=0.030). R₂₀ predicted pyeloplasty with a sensitivity of 88.3%, specificity of 56%, the area under the ROC curve of 0.758 (95% CI 0.667-0.850, P=0.000), and the cut-off value of 90.08%. During the follow-up, 38 children underwent the second diuretic renal scintigraphy, and the DRF was lower than before. The difference between the two DRFs was statistically significant (Z=-2.589, P=0.010), especially in children with R₂₀≥90.08% (Z=-2.166, P=0.030). R₂₀ in the non-operation group decreased significantly compared with the baseline (Z=-2.062, P=0.039). However, R₂₀ in the operation group was higher than baseline, but the difference was not statistically significant (P>0.05). Conclusion ·R₂₀ plays an important role in the prediction of pyeloplasty in children with congenital unilateral UPJO. For children with R₂₀≥90.08%, pyeloplasty should be performed as soon as possible to prevent further deterioration of renal function.