The purpose of this study is to establish renal resistive index (RRI) of normal kidneys in puppies aged from newborn to 20 weeks of age and to determine the age at which RRI reaches adult dog values. Six healthy adult intact beagles and six puppies from 1 day after birth to 20 weeks of age were used. In the adult dogs, the ultrasonographic scans were performed once, and in the puppies, the ultrasonographic studies were performed on the first day after birth and at 1, 2, 3, 4, 6, 8, 12, 16, and 20 weeks of age. RRI was obtained at the interlobular and arcuate arteries in each kidney. There were no statistical differences between the RRI values obtained between the right and left kidney nor between intrarenal arteries (interlobar and arcuate). The RRI was the highest during the first weeks of life, after which it declined gradually with increasing age reaching adult dog values at 12 weeks of age. In conclusion, the normal mean RRI is age dependent in dogs. Twelve weeks can be regarded as the age at which adult mean RRI criteria can be applied to puppies.

中文翻译：

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在生命的头几个月中，健康幼犬的肾电阻指数值发生变化。

这项研究的目的是确定从新生到20周龄的幼犬的正常肾脏的肾电阻指数（RRI），并确定RRI达到成年狗值的年龄。从出生后1天到20周龄，使用了六只健康的成年完整小猎犬和六只幼犬。在成年犬中，进行一次超声检查，在幼犬中，在出生后的第一天以及出生后1、2、3、4、6、8、12、16和20周进行超声检查。年龄。RRI是在每个肾脏的小叶间和弓形动脉中获得的。在左右肾脏之间以及肾内动脉（叶间和弓形）之间获得的RRI值之间无统计学差异。在生命的最初几周中，RRI最高 之后，随着年龄的增长，它逐渐下降，到12周龄时达到成年狗的价值。总之，狗的正常平均RRI与年龄有关。可以将十二周视为成年平均RRI标准适用于幼犬的年龄。