Abstract
BACKGROUND: Some kidney diseases are usually associated with changes in kidney size. OBJECTIVE: To determine sonographically the normal limits and percentile curves of the kidney dimensions according to age, gender and somatometric parameters among school-age children. METHODS: A prospective cross-sectional research design and convenience sampling method were utilized. Participants included 947 normal subjects (496 boys and 451 girls) aged 6-17 years old. The sonographic examination was performed on a Shenzhen DP-1100 machine with 3.5 MHz convex transducer. Longitudinal and transverse dimensions of the kidneys were obtained in coronal plane with the subject in the supine or left lateral decubitus position. RESULTS: The means of right and left kidney lengths in mm were 79.6 ± 8.1 and 81.6 ± 8.3, respectively while that of the right and left kidney widths in mm were 35.03 ± 3.6 and 35.09 ± 3.6, respectively. Dimensions of the kidneys were not statistically different in boys and girls (p > 0.05). There was a statistically significant difference between right and left kidney length (p < 0.05). Height correlated best with both kidney lengths. Thus the normal limits, prediction models and percentile curves of kidney lengths were established with respect to height. CONCLUSION: Sonographic determination of pathologic changes in the size of the kidneys necessitates knowing the normal ranges of its lengths especially with respect to height in school-age children.