BACKGROUND Ultrasound (US) is used in the initial evaluation and surveillance of urinary tract dilation in children. Urinary tract dilation is diagnosed in 1-2% of all pregnancies during routine prenatal sonography with technological advances in US imaging. Urinary tract dilation classification systems, including the 2014 multidisciplinary consensus, assess anterior-posterior renal pelvic diameter and calyceal dilation. There is no consensus regarding optimal patient positioning - supine versus prone - during US assessment of urinary tract dilation. OBJECTIVE We performed this study to determine whether there is a significant difference in the measurement of the anterior-posterior renal pelvic diameter, presence of calyceal dilation, or resulting urinary tract dilation consensus score obtained between supine and prone positions. MATERIALS AND METHODS Two raters retrospectively reviewed renal bladder US exams of children with urinary tract dilation of one or both kidneys. We included technically adequate US examinations of orthotopic kidneys that were imaged in both supine and prone positions; we excluded children with renal anomalies or prior surgery. Anterior-posterior renal pelvic diameter measurements as well as central and peripheral calyceal dilation were documented in both supine and prone positions. A postnatal urinary tract dilation consensus score was assigned to each kidney based only on these features. RESULTS Urinary tract dilation in either the supine or prone position was performed in 146 kidneys (69 right, 77 left) in 89 children. Median age was 0.26 years (interquartile ratio [IQR] 0.08-0.61 years). Female-to-male ratio was 1:3 (21/89). The interclass correlations of the anterior-posterior renal pelvic diameter were 0.88 and 0.87 in the supine and prone positions, respectively, without significant differences (P=0.1). When comparing all kidneys together, the mean anterior-posterior renal pelvic diameter was 7.1 mm (95% confidence interval [CI] 6.4-7.8) in supine and 7.9 (95% CI 7.1-8.7) in prone, with a mean difference between the measurements of 0.83 mm (95% CI 0.3-1.4; P=0.16). Central calyceal and peripheral calyceal dilation were more commonly found in the prone position versus the supine position in both kidneys. Central calyceal dilation was observed in 15 cases in the prone but not in the supine position. In one kidney, it was seen only in the supine but not in the prone position. Overall the urinary tract dilation score differed between positions in 10.3% (15/146) of cases, most of them (14/15) with a higher score in prone compared to the supine position. CONCLUSION Scanning in prone position tends to more frequently show calyceal dilation and a greater size of the anterior-posterior renal pelvic diameter, resulting in higher urinary tract dilation classification scores, with almost perfect interobserver agreement.

中文翻译：

---

仰卧位与俯卧位对儿童产后泌尿道扩张的超声评估。

背景技术超声（US）被用于儿童尿路扩张的初步评估和监测。随着美国影像技术的发展，在常规产前超声检查中，所有妊娠中有1-2％的人诊断为尿路扩张。尿路扩张分类系统，包括2014年的多学科共识，评估肾盂前后直径和肾盂扩张。在美国评估尿路扩张过程中，关于最佳患者定位（仰卧还是俯卧）尚无共识。目的我们进行了这项研究，以确定在仰卧位和俯卧位之间测量前后肾盂直径，是否存在肾盂扩张或尿路扩张共识得分是否存在显着差异。材料与方法两名评估者回顾性审查了一个或两个肾脏的尿路扩张患儿的美国肾脏检查。我们纳入了技术上足够的美国仰卧位和俯卧位成像的原位肾脏检查；我们排除了患有肾脏异常或先前手术的儿童。仰卧位和俯卧位都记录了肾盂前后直径的测量以及中央和周围的肾盂扩张。仅基于这些特征，将产后泌尿道扩张共识评分分配给每个肾脏。结果89例患儿的146只肾脏（右69头，左77头）行仰卧位或俯卧位尿路扩张术。中位年龄为0.26岁（四分位数比[IQR] 0.08-0.61岁）。男女比例为1：3（21/89）。仰卧位和俯卧位肾盂前后直径的类别间相关性分别为0.88和0.87，无显着差异（P = 0.1）。比较所有肾脏时，仰卧位的平均前后骨盆直径为仰卧位的平均直径为7.1 mm（95％置信区间[CI] 6.4-7.8），俯卧位的平均前后直径为7.9（95％CI 7.1-8.7），测量值为0.83毫米（95％CI 0.3-1.4； P = 0.16）。在两个肾脏的俯卧位相对于仰卧位更常见于中央肾上腺和外周肾上腺扩张。在15例俯卧但未仰卧位的病例中观察到中央肾盂扩张。在一个肾脏中，仅在仰卧位看到它，而俯卧位没有看到它。总体而言，尿路扩张评分在10个位置之间存在差异。3％（15/146）的病例中，大多数病例（14/15）的俯卧位得分高于仰卧位。结论俯卧位扫描倾向于显示肾盂扩张和肾盂前后直径较大，导致尿路扩张分类评分更高，观察者之间的观察结果几乎完美。