Sargent M A, Gupta S C
Department of Radiology, Royal Manchester Children's Hospital, Pendlebury, United Kingdom.
AJR Am J Roentgenol. 1993 Jul;161(1):157-60. doi: 10.2214/ajr.161.1.8390789.
Observer error in the sonographic estimation of renal volume in children has not been reported. Knowledge of the possible magnitude of error is important in assessing abnormalities of renal growth. This study was undertaken to determine the error of sonographic measurements of relative renal volume by comparing them with measurements of relative renal function from 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy.
The study included 52 children, 2 months to 16 years old, who had DMSA scintigraphy and renal sonography on the same day. The sonographic and scintigraphic studies were interpreted independently. Relative function of the right kidney as shown by DMSA scintigrams in the direct posterior view was compared with relative volume as determined with sonography. Renal volumes were calculated by using the formula for a prolate ellipsoid. The standard deviation of the differences (SDD) between relative renal function and relative renal volume was calculated, and the limits of agreement were derived.
Thirty-three children had normal renal morphology on both studies. Twenty-five kidneys in 19 children were abnormal on one or both studies, including 14 definitely scarred kidneys in 12 children. Relative function of the right kidney in patients with normal kidneys was 50.1 +/- 2.5%, including one possible outlying value. Normal relative volume of the right kidney was 49.1 +/- 3.1%. In patients with normal kidneys, the difference between relative function and relative volume of the right kidney was 1.0 +/- 2.8% with 95% limits of agreement of 6.7% and -4.7%. Agreement between relative function and relative volume was worse for children with abnormal kidneys; the mean difference was 2.0%, and the largest observed difference was 10.9%. Correlation between relative renal volume and relative renal function for all patients was high (r = .94), with 95% limits of agreement of 8.6% and -5.8%.
The agreement between relative renal function and relative renal volume was good. In children with normal kidneys, estimated relative renal volume derived from sonography can be expected to lie within 6.7% of the relative renal function determined scintigraphically.
儿童肾脏体积超声估计中的观察者误差尚未见报道。了解可能的误差大小对于评估肾脏生长异常很重要。本研究旨在通过将超声测量的相对肾脏体积与99mTc-二巯基丁二酸（DMSA）闪烁扫描法测量的相对肾功能进行比较，来确定超声测量相对肾脏体积的误差。
本研究纳入了52名年龄在2个月至16岁之间的儿童，他们在同一天进行了DMSA闪烁扫描和肾脏超声检查。超声和闪烁扫描研究由不同人员独立解读。将直接后位DMSA闪烁图显示的右肾相对功能与超声测定的相对体积进行比较。肾脏体积采用长椭球体公式计算。计算相对肾功能与相对肾脏体积之间差异的标准差（SDD），并得出一致性界限。
两项检查中33名儿童的肾脏形态正常。19名儿童的25个肾脏在一项或两项检查中异常，其中12名儿童的14个肾脏有明确瘢痕。肾脏正常的患者右肾相对功能为50.1±2.5%，包括一个可能的离群值。右肾正常相对体积为49.1±3.1%。肾脏正常的患者中，右肾相对功能与相对体积的差异为1.0±2.8%，95%一致性界限为6.7%和-4.7%。肾脏异常儿童的相对功能与相对体积之间的一致性较差；平均差异为2.0%，观察到的最大差异为10.9%。所有患者相对肾脏体积与相对肾功能之间的相关性较高（r = 0.94），95%一致性界限为8.6%和-5.8%。
相对肾功能与相对肾脏体积之间的一致性良好。在肾脏正常的儿童中，超声估计的相对肾脏体积预计在闪烁扫描法测定的相对肾功能的6.7%范围内。
