Koff S A, Binkovitz L, Coley B, Jayanthi V R
Children's Hospital, Columbus, Ohio, USA.
J Urol. 2005 Jul;174(1):303-7. doi: 10.1097/01.ju.0000161217.47446.0b.
We measured the volume of the renal pelvis during diuretic renography (DR) in children with normal and hydronephrotic kidneys to determine if changes in pelvic volume could affect the accuracy of DR in diagnosing obstruction.
We studied 18 patients 1 month to 10 years old with unilateral hydronephrosis ultimately proved to be either obstructive or nonobstructive. Simultaneous DR and ultrasound were performed with patients supine using the gamma camera. Ultrasound measurements of the renal pelvis in 3 dimensions, obtained before and at intervals after diuretic injection, were used to calculate renal pelvic volume. The contralateral normal kidneys were used as controls.
Between 15 and 60 minutes after diuretic injection the renal pelvis enlarged to a maximum volume in all hydronephrotic and normal kidneys and then gradually decreased in size. Mean average increase in volume for hydronephrotic kidneys ranged from 46% in obstructed kidneys to 88% in nonobstructed kidneys. Volume expansion caused dilution of isotope within the renal pelvis, which resulted in prolongation of elimination half-time (T1/2) in 42% of nonobstructed hydronephrotic kidneys sufficient to register an obstructed washout pattern. However, there were no differences in the initial pelvic volume or the rate or extent of increases or decreases in pelvic volume that would permit nonobstructed hydronephrotic kidneys to be distinguished from obstructed ones.
The renal pelvis enlarges during diuresis in children with hydronephrosis. This enlargement causes dilution of isotope within the renal pelvis during DR, which prolonged the isotope washout rate or T1/2 sufficiently to produce an obstructed washout pattern in more than 40% of hydronephrotic kidneys that were ultimately proved to be nonobstructed. This misdiagnosis of obstruction is particularly likely to occur in children younger than 2 years because pelvic volume expansion is so exaggerated. Consequently, T1/2 appears to be particularly vulnerable to inaccuracy in diagnosing obstruction in this age group, and, therefore, it should not be relied on as an operative determinant.
我们测量了正常肾脏和肾积水患儿在利尿肾图（DR）检查期间肾盂的体积，以确定肾盂体积变化是否会影响DR诊断梗阻的准确性。
我们研究了18例年龄在1个月至10岁之间的单侧肾积水患者，最终证实为梗阻性或非梗阻性。患者仰卧位时使用γ相机同时进行DR和超声检查。在注射利尿剂之前及之后的不同时间间隔获取肾盂的三维超声测量值，用于计算肾盂体积。对侧正常肾脏用作对照。
注射利尿剂后15至60分钟内，所有肾积水和正常肾脏的肾盂均增大至最大体积，然后逐渐缩小。肾积水肾脏的平均体积增加范围从梗阻性肾脏的46%到非梗阻性肾脏的88%。体积扩张导致肾盂内同位素稀释，这使得42%的非梗阻性肾积水肾脏的消除半衰期（T1/2）延长，足以记录为梗阻性洗脱模式。然而，初始肾盂体积或肾盂体积增加或减少的速率或程度并无差异，无法区分非梗阻性肾积水肾脏与梗阻性肾积水肾脏。
肾积水患儿在利尿过程中肾盂会增大。这种增大在DR期间导致肾盂内同位素稀释，使同位素洗脱率或T1/2延长，足以在最终被证明为非梗阻性的超过40%的肾积水肾脏中产生梗阻性洗脱模式。这种梗阻的误诊在2岁以下儿童中尤其可能发生，因为肾盂体积扩张非常明显。因此，T1/2在该年龄组中诊断梗阻时似乎特别容易出现不准确情况，所以不应将其作为手术决定因素。
