Ultrasonographic renal volume in Chinese children: Results of 1683 cases

Background: At present, little information has been made available in the evaluation of renal volume in pediatric groups of different ages.

Purpose: The purposes of the study are to evaluate the relationship between anthropometric measurements and renal volume measured with three-dimensional ultrasonography in Chinese children who have normal kidneys, and to attempt to develop reliable reference values of renal volume to estimate the renal sizes.

Methods: A total of 1572 Chinese Han children suffering from stomachache, cryptorchidism and neurogenic enuresis with no history of renal disease or pathological abnormalities that might affect measurements, aged 1month to 12years (mean, 5.64years) were examined bilateral kidneys by ultrasonography. The measurements of renal volume were determined using QLAB software in IU22 units (Philips Medical Systems, Holland). Anthropometric indices including sex, age, height and weight were collected for reviewed analysis.

Results: A total of 1683 children were included, and renal volume of 1572 cases (93.4%) was accepted. There was no significant difference between renal volumes of male and female separately in left and right kidneys (P=0.844 and P=0.621, respectively), whereas there was a significant difference between mean left and right renal volumes (P=0.000). Age, height and weight were all significant correlations with renal volume (R(2), 0.885 and 0.913 for the left and right kidneys, respectively, both P=0.000), and age was the strongest correlation with renal volume (r, 0.472 and 0.399 for the left and right kidneys, respectively) among the anthropometric indices. We drew regression equations to estimate renal volume as follows: left renal volume (cm(3))=0.441×age+0.156×height+0.398×weight+6.677 and right renal volume (cm(3))=0.256×age+0.195×height+0.632×weight+1.788, and developed reference values of renal volume separately for the left and right kidneys in different age groups.

Conclusions: Regression equations have been developed, which define the renal volume from three-dimensional ultrasonography and may assist pediatricians in monitoring renal growth and detecting of unsuspected bilateral increases or decreases in renal size.