Sonographic Assessment of Renal Size in Healthy Adults

OBJECTIVE To assess the normal sonographic values of renal length and cortical thickness in healthy adults and establish reference ranges in our population for comparison when examining renal disease. SUBJECTS AND METHODS Sonographic assessment of renal length and cortical thickness were performed from January 2006 to December 2011 in 252 healthy individuals who were self-referred to the El-Reshaid Renal Clinic in Kuwait. They were screened for the absence of renal abnormalities. Weight and height were measured, and body mass index (BMI) and body surface area calculated. Patients were divided into 5 age groups: 18-30, 31-40, 41-50, 51-60 and 61-80 years, in order to generate reference graphs for renal length and cortical thickness. RESULTS The mean renal lengths for the right and left kidney were 10.68 ± 1.4 and 10.71 ± 1.0 cm, respectively (p = 0.56) without a significant change with age. The minimum cortical thickness was 0.6 cm. The renal length correlated with the weight of the patients (p < 0.01) and their BMI (p < 0.01) but not with their height. There was no difference in renal size or cortical thickness in patients older than 60 years despite an age-related decline in the glomerular filtration rate (p < 0.001). CONCLUSIONS Renal length and cortical thickness did not vary significantly with age. Renal length correlated well with weight and BMI but not with height. Hence, establishing normal ranges of renal parameters is essential for comparison in situations where possible renal disease is being investigated.