Ultrasound measurements of renal internal structures in patients with chronic kidney disease

This study aimed to assess the differences of renal cortical thickness, renal medullary pyramid thickness, renal volume, renal sinus length and thickness between CKD and healthy groups. It was also designed to determine which parameter(s) is/are more likely to predict CKD.

A total of 40 subjects (80 kidneys) were recruited in this observational study and divided into two groups: healthy and CKD. B-mode ultrasound was performed to measure the following parameters: renal cortical thickness, renal volume, renal medullary pyramid thickness, renal sinus length and thickness. These measurements were compared between both groups.

A total of 80 kidneys (55 normal and 25 diagnosed with CKD) were examined by ultrasound. Significant decrease in renal cortical thickness (p = 0.028), renal medullary pyramid thickness (p = 0.011), renal sinus length (p = 0.011) in favor of CKD as compared with healthy group. Furthermore, every one unit decrease in renal cortical thickness (p < 0.001, OR = 0.205, 95% CI = 0.095–0.443), renal medullary pyramid thickness (p < 0.001, OR = 0.579, 95% CI = 0.433–0.776) and renal sinus length (p = 0.022, OR = 0.976, 95% CI = 0.956–0.997) can significantly predict CKD. However, a decrease in renal cortical thickness was more probably to predict CKD (p = 0.001, OR = 0.261, 95% CI = 0.120–0.571). Moreover, renal cortical thickness ≤ 6.35 mm was significant predictor of CKD (AUC = 0.885, sensitivity = 92%, specificity = 67.3%, P < 0.001). Renal medullary pyramid thickness had 79% chance to significantly diagnose CKD (AUC = 0.790) with sensitivity of 84.0% and specificity of 65.5% at thickness ≤ 10.45 mm.

Decrease in renal cortical thickness and renal medullary pyramid thickness is the most important indicator of CKD.