Abstract: ［Abstract］ Objective To evaluate the predictable effect of prostatic urethra length（PU）on bladder outlet obstruction（BOO）in patients with low urinary tract symptoms（LUTS）basing on investigating the correlation between PU segmental length，prostatic volume （PV），residual urine （RU） and BOO. Methods Clinical data of 168 outpatients or hospitalized males with LUTS were collected from January 2014 to June 2017. PU，superior prostatic urethra length （SPU），inferior prostatic urethra length （IPU），ratio of SPU and IPU（SIR），PV were measured and calculated by transrectal ultrasonography. The residual urine（RU）was measured and calculated by transabdominal ultrasonography. Bladder outlet obstruction index（BOOI）was recorded by uroflowmetry. BOO was defined by a BOOI above 40. Firstly， the data were divided into two groups accordingly BOOI≥40 and BOOI<40. Statistical significance of mean value was compared between two groups. Correlation was analyzed between BOOI and PU ，SPU， IPU，SIR，PV，RU and age. Univariate analysis was used to screen the risk factors of BOO. Receiver operating characteristic curves （ROC） were used to evaluate PU， SPU， IPU， SIR， PV， RU in predicting BOO in patients with LTUS. Results The proportion of BOO was 58.9%（99/168）in our study. BOO in LUTS patients correlated positively with SIR，SPU，RU，PU，PV（r=0.427，P=0.001；r= 0.387，P=0.027；r=0.313，P=0.019；r=0.308，P=0.032；r=0.269，P=0.038），whereas uncorrelated with IPU and age（r=0.159，P=0.147；r=0.118，P=0.063，respectively）. The positive predictive value of SIR took up the highest percentage amongst these parameters（75.2%，76/101）. Significant difference of SIR was found between the groups of BOOI≥40 and BOOI<40 in LTUS patients（t=3.856，P=0.002）. The incidence rate of the BOO was higher in group of SIR≥1.5 than that of SIR<1.5（?2=20.563，P< 0.001）. The area under curve（AUC）of the ROC of SIR in predicting BOO in LTUS patients was 0.729± 0.061（P=0.002），and optimal cut-off value was SIR≥1.5. The parameter of SIR≥1.5 could predict presence of BOO in LUTS patients with a sensitivity of 66.8% and specificity of 90.1% . Conclusion SIR，SPU，PU，RU，PV positively correlate with the incidence of BOO in patients with LUTS.SIR manifests a better predictor over these parameters. Patients with SIR≥1.5 are at a higher risk for BOO than those with SIR<1.5 with a favorite specificity and fairly sensitivity.

Key words: prostate, ultrasonography, lower urinary tract symptoms, bladder outlet obstruction

摘要： ［摘要］ 目的 研究男性下尿路症状（LUTS）患者的膀胱出口梗阻（BOO）与前列腺部尿道长度、前列腺体积之间的相关性，探讨前列腺部尿道上下段长度及其比例对 BOO 的预测价值。方法 选择 2014 年 1 月至 2017 年 6 月广州新海医院 168 例男性 LUTS 门诊或住院患者，未经任何治疗。经直肠超声测量前列腺部尿道长度（PU）、上段长段（SPU）、下段长度（IPU），计算上下段长度之比（SIR）；测量并计算前列腺体积（PV），经腹超声测量并计算膀胱残余尿量（RU）。尿流动力学检测仪记录膀胱梗阻指数（BOOI），以 BOOI≥40 判断为 BOO。首先根据BOOI≥40 与 BOOI<40 将资料分为 2 组，比较 2 组间上述参数的统计学差异；分析其与前列腺部尿道各段长度及比例、前列腺体积、膀胱残余尿之间的相关性；然后以单因素分析筛选 LUTS 患者 BOOI 的影响因素；最后建立受试者操作特性曲线（ROC）评估各参数预测 LUTS 患者 BOO 的价值。结果 本组 LUTS 患者中 99 例诊断为 BOO（58.9%），BOOI 与SIR、SPU、RU、PU、PV 均有相关性（r=0.427，P=0.001；r=0.387，P=0.027；r=0.313，P=0.019；r=0.308，P=0.032；r=0.269，P=0.038）；与 IPU、age 无相关 性（r=0.159，P=0.147；r=0.118，P=0.063）。 SIR 的阳性预测值最高（75.2% ，76/101）。SIR 在 BOOI≥40 与 BOOI<40 两组间相比有统计学意义（t=3.856，P=0.002）；SIR≥1.5 的患者 BOO 发生率明显高于SIR<1.5 患者（?2=20.563，P=0.000）。ROC 分析，以 SIR 预测LUTS 患者 BOO 的 ROC 曲线下面积（Area under curve，UC）为 0.729±0.061，P=0.002，最佳分界值为 1.5，以 SIR≥1.5 来预测有 BOO，敏感性为 66.8% ，特异性为 90.1% 。结论 LUTS 患者 SIR、 SPU、PU、RU、PV 均与 BOO 呈正相关；SIR 的阳性预测值最高，AUC 最大，以 SIR≥1.5 预测 BOO的特异性较高，但敏感性较差。

关键词: 超声检查, 下尿路症状, 膀胱出口梗阻, 前列腺