Normal values for renal parenchymal volume and kidney length as measured by non-enhanced multidetector spiral computed tomography.

Background: Renal parenchymal volume (RPV) is considered an important index for clinical decisions. However, normal values have not been established, which hinders the clinical application of RPV.

Purpose: To test the accuracy and reproducibility of RPV and to investigate the normal values of RPV and kidney length as measured by non-enhanced multidetector computed tomography (CT).

Material And Methods: An animal model study was performed to test the accuracy and repeatability of RPV measured by CT. RPV of porcine kidneys was measured by water displacement (actual values) and non-enhanced multidetector CT. Individual RPV and kidney length were measured by non-enhanced CT in patients with no clinical history of renal disease (n = 722). Patient height, age, weight, body surface area (BSA), and body mass index (BMI) were assessed before each patient's CT examination was performed.

Results: RPV obtained by the CT method was within 2% of the RPV determined by the water displacement method. The normal values of RPV (M ± 1.96 standard deviation [SD]) were 145.72 ± 54.37 mL for men and 132.46 ± 41.94 mL for women. The normal values of kidney length (M ± 1.96 SD) were 10.27 ± 1.98 cm for men and 9.93 ± 1.58 cm for women. RPV did not significantly correlate with BSA or weight in women, but correlated significantly with height and age in both men and women. Of the assessed factors age, weight, height, BSA, and BMI, age, and height were the independent factors that best reflected RPV, in both men and women.

Conclusion: The present animal study results showed that non-enhanced multidetector CT findings accurately reflect the RPV. The subsequent study performed in humans showed that the RPV of the presently sampled Chinese population was lower than the commonly quoted reference values obtained from Western populations.