Volumetric evaluation of fat in the renal sinus in normal subjects using stereological method on computed tomography images and its relationship with body composition.

Background: The aim of the study was: to describe a simple, accurate and practical technique for estimating the volume of adipose tissue within the renal sinus (RS) using stereological method on computed tomography (CT) images; to establish a population database for volume of fat within the RS from 21 to 80 years of age; to investigate the effect of age, gender, body mass index (BMI) and abdominal diameters on RS fat volume in normal subjects. Materials and methods: We retrospectively reviewed abdominal CT examinations of 240 patients without renal pathology between the ages of 21 and 80 years. There were 6 groups of patients, with 40 patients for each decade. Results: RS fat volumes in the left and right kidney were 5.70 ± 2.87 cm 3 and 4.15 ± 2.39 cm 3 , respectively, in males and 3.51 ± 2.67 cm 3 and 2.49 ± 2.16 cm 3 , respectively, in females. RS fat volume and age were positively correlated for both kidneys (left: r = 0.46; right: r = 0.44; p < 0.001, both), though it appeared to decline after age 70. Conclusions: Quantitative data may allow clinicians to better estimate the age-related RS fat volume changes and help them in decision making.