Persutte W H, Hussey M, Chyu J, Hobbins J C
Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver, USA.
Ultrasound Obstet Gynecol. 2000 Mar;15(3):186-90. doi: 10.1046/j.1469-0705.2000.00032.x.
Using strict thresholds of normality, investigators have reported associations between fetal pyelectasis and aneuploidy, obstructive uropathy, postnatal pyeloplasty and vesicoureteral reflux. Although evidence continues to mount regarding the importance of fetal pyelectasis, little is known of the variability of collecting system measurements. To investigate the short-term variability and its relationship to bladder dilatation, the following study was conducted.
During May and June 1996, 20 mid- and late-trimester patients with varying degrees of fetal pyelectasis were recruited into this study. Each consented to undergo periodic (every 15 min for 2 h) ultrasound measurements of the fetal renal collecting systems and bladder. To account for anatomic and technical variability in measurement, we used both the sum of the transverse and anterior-posterior (AP) measurements of the collecting systems, and AP measurement alone for comparison. The variability of the collecting system measurements was assessed based upon gestational age, magnitude of pyelectasis and fetal bladder size.
We investigated 38 renal units in 20 patients (eight in the second trimester and 12 in the third). The mean(SE) AP diameter of all kidneys was 5.89(2.49) mm (range 15 (2-17) mm), and the sum of transverse and AP renal collecting system diameters was 13.91(5.73) mm (range 26 (4-31) mm). These data were normally distributed. When assessing the variability in individual kidneys over time, we found the mean variation (minimum to maximum) for the sum of the AP and transverse measurement to be 7.61(4.26) mm and for the AP measurement alone to be 3.80(2.49) mm. No relationship was found between variability of dilatation, magnitude of dilatation or fetal bladder size. Cyclic dilatation of the fetal bladder was observed in all cases. The mean time from maximal to minimal dilatation was 20 min (1.34 observations; range 12-30 min).
We found the size of the fetal renal collecting system to be highly variable over the course of a 2-h period. Seventy per cent of cases (14 of 20) had both normal (< 4 mm) and abnormal values (> or = 4 mm) during the 2-h study period. Significant caution should be used when considering the implications of renal collecting system dilatation based upon a single AP measurement.
研究人员采用严格的正常标准，报告了胎儿肾盂扩张与非整倍体、梗阻性泌尿系统疾病、产后肾盂成形术及膀胱输尿管反流之间的关联。尽管关于胎儿肾盂扩张重要性的证据不断增加，但对于集合系统测量值的变异性却知之甚少。为了研究短期变异性及其与膀胱扩张的关系，开展了以下研究。
1996年5月至6月期间，招募了20例中晚期妊娠且伴有不同程度胎儿肾盂扩张的患者参与本研究。每位患者均同意接受对胎儿肾集合系统和膀胱进行定期（每15分钟一次，共2小时）超声测量。为了考虑测量中的解剖学和技术变异性，我们同时使用了集合系统横径与前后径测量值之和以及单独的前后径测量值进行比较。基于胎龄、肾盂扩张程度和胎儿膀胱大小评估集合系统测量值的变异性。
我们对20例患者的38个肾单位进行了研究（孕中期8个，孕晚期12个）。所有肾脏的平均（标准误）前后径为5.89（2.49）mm（范围为2 - 17 mm），肾集合系统横径与前后径之和为13.91（5.73）mm（范围为4 - 31 mm）。这些数据呈正态分布。在评估单个肾脏随时间的变异性时，我们发现前后径与横径测量值之和的平均变化（最小值至最大值）为7.61（4.26）mm，单独前后径测量值的平均变化为3.80（2.49）mm。未发现扩张变异性、扩张程度或胎儿膀胱大小之间存在关联。在所有病例中均观察到胎儿膀胱的周期性扩张。从最大扩张到最小扩张的平均时间为20分钟（1.34次观察；范围为12 - 30分钟）。
我们发现胎儿肾集合系统的大小在2小时内变化很大。在2小时的研究期间，70%的病例（20例中的14例）既有正常（<4 mm）值又有异常（≥4 mm）值。基于单次前后径测量考虑肾集合系统扩张的影响时应格外谨慎。
