The Correlation between Renal Cortical Thickness by Renal Ultrasonography and Comprehensive Renal Function Study in Patients with Obstructive Uropathy

Purpose: Renalfunction assessed by conventional renal ultrasonography in patients with obstructive uropathy was evaluated to provide a valuable parameter for decision-making pre-operatively. Materials and Methods: Results from patients with unilateral obstructive uropathy who received both Iodine-131 orthoiodohippurate (OIH) comprehensive renal function test and conventional sonography of kidney were analyzed retrospectively. The correlation between effective renal plasma flow (ERPF) and sum of the thickness of upper, middle, and lower portion in obstructed renal units (Group I) and non-obstructed (Group II) renal units were analyzed with linear regression method. Results: A total of 60 patients (120 renal units) were analyzed. In Group I kidneys, the sum of the renal cortical thickness was 43.4±20.6 mm and ERPF was 107.0±81.8 ml/min. In Group II, the sum of the renal cortical thickness was 69.3±12.4 mm and the ERPF was 248.8±1 05.2 ml/mm. There was no correlation between ERPF and the sonographic-estimated thickness between obstructive (r2= 0.404) and non-obstructive (r2 = 0.054) kidneys Conclusion: Sonography provides non-invasive and convenient anatomical information about the obstructed kidneys, but renal function still cannot be estimated by this modality.