肾积液CT值对结石梗阻性肾积脓的诊断价值

Diagnostic value of CT attenuation value of hydronephrosis in calculous obstructive pyonephrosis

目的探讨肾积液CT值对结石梗阻性肾积脓的诊断价值。方法收集140例上尿路结石梗阻致肾积液患者,选择其中53例肾积脓患者为观察组、87例肾积水患者为对照组。测定所有患者的肾积液CT值,绘制受试者工作特征曲线(ROC),计算ROC曲线下面积(AUC),确定诊断肾积脓的截断值,分析肾积液CT值对结石梗阻性肾积脓的诊断效能。结果观察组53例患者肾积脓的CT值为(13.5±7.3)Hu,高于对照组87例患者肾积水的CT值(5.4±4.2)Hu(P<0.01)。肾积液CT值鉴别结石梗阻性肾积脓和肾积水的ROC AUC为0.823,95%CI为0.747~0.899。当肾积液CT值为10.5 Hu时,约登指数最大,为0.553。以CT值≥10.5 Hu作为诊断梗阻性肾积脓的参数标准,其灵敏度、特异度、阳性预测值、阴性预测值、假阳性率、假阴性率和准确度分别为68%、87%、77%、82%、32%、23%和80%。结论肾积液CT值测定对上尿路结石梗阻患者术前肾积脓诊断的评估以及手术方案的制定具有重要的预测价值。

Objective To investigate the diagnostic value of CT attenuation value of hydronephrosis in calculous obstructive pyonephrosis. Methods Clinical data of 140 patients with hydronephrosis induced by calculous obstruction of the upper urinary tract were retrospectively analyzed. Among them, 53 patients with pyonephrosis were assigned into the observation group and 87 cases with hydronephrosis were recruited into the control group. The CT attenuation values of hydronephrosis in all patients were measured. The receiver operating characteristic curve （ROC） was delineated to calculate the area under the ROC curve （AUC ） . The cut-off point for the diagnosis of pyonephrosis was determined. The diagnostic efficacy of CT value of hydronephrosis in calculous obstructive pyonephrosis was evaluated. Results In the observation group, the average CT attenuation value of 53 patients with pyonephrosis was （13.5±7.3） Hu, significantly higher compared with （5.4±4.2） Hu for 87 cases with hydronephrosis in the control group （ P 〈0.01 ） . The AUC of CT attenuation value of hydronephrosis in the differential diagnosis from pyonephrosis to hydronephrosis was 0.823 and 95% confidence interval was 0.747-0.899. When the CT attenuation value of hydronephrosis was 10.5 Hu, the maximum Youden index was 0.553. Therefore, the CT attenuation value of hydronephrosis of 〉 10.5 Hu could be used as the standard for the diagnosis of calculous obstructive pyonephrosis. The sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy rate were 68%, 87%, 77%, 82%, 32%, 23% and 80%, respectively. Conclusion CT attenuation value of hydronephrosis is of significant predictive value for the assessment of preoperative diagnosis and establishment of surgical procedures in patients with calculous obstruction of the upper urinary tract.