Normal Renal Dimensions in Iranian Adults Measured by Ultrasound

Introduction: Correct interpretation of kidney images requires the knowledge of its normal&nbsp;size. This study aimed to establish normal values for kidney length and parenchymal thickness&nbsp;and identify the potential related factors in a group of Iranian adults. Methods: Renal dimensions, including length and parenchymal thickness were measured&nbsp;by sonography in 103 individuals with no renal disease. Statistical analyses were done to&nbsp;find the effect of different variables such as side, age, and gender using 2-tailed t-test, Mann-Whitney test, paired t test, and Wilcoxon-signed rank test. The correlation of renal dimensions&nbsp;with anthropometric parameters, including weight, height, and body mass index (BMI) was&nbsp;analyzed using the Pearson correlation coefficient. Results: Mean (SD) kidney length was 104.96(6.6) mm for the right, and 106.22(6.16) mm for&nbsp;the left kidney (P=0.02). Mean (SD) parenchymal thickness for the right kidney was 16.9(1.6)&nbsp;mm and on the left side, it was 18.2(1.7) mm (P<0.001). Gender related analysis showed&nbsp;significant differences between male and female renal length and parenchymal thickness&nbsp;(P<0.05). Age group analysis regardless of sex showed significant decrease in renal length&nbsp;and parenchymal thickness beyond the fifth decade of life. There was a positive correlation&nbsp;between bilateral renal length and body weight as well as BMI. Also, there was a weak positive&nbsp;correlation with body height. Conclusion: Because of several factors affecting on kidney size, its assessment should be made&nbsp;individually. The important influencing factors are ethnicity, gender, age, BMI, and height.