Correlation of Ultrasound Parameters with Serum Creatinine in Renal Parenchymal Disease

Introduction: Chronic kidney disease (CKD) is common cause of renal failure. It involves a progressive loss in the structure and function of the kidneys over the course of months, with or without decreased glomerular filtration rate (GFR). CKD can be diagnosed by its pathological abnormalities, changes in the levels of renal function markers in the blood or urine, or by imaging investigations (E.g. USG etc). Objectives: The purpose of our study is 1) To correlate renal echogenicity with serum creatinine in order to determine the significance of renal echogenicity for identifying the progression of chronic kidney disease (CKD) and for the sonographic grading of CKD, 2) To study association of blood pressure, renal cortical cysts and renal size with grade of chronic renal disease. Methods: This hospital based cross sectional study was carried out at National Kidney Centre, Banasthali Kathmandu. Two hundred patients above 20 years, diagnosed with CKD according to the guidelines of the National Kidney Foundation and referred for USG, were included in the study. Patients with kidney transplant, on dialysis, with liver disease and renal tumors were excluded. Ultrasound of kidneys was performed by senior consultant radiologist who was blind to the patients’ serum creatinine levels. The relationship between grade of CKD with serum creatinine, kidney size, blood pressure and cortical cysts were assessed. Statistical analysis was performed by Kruskal wallis test using SPSS version 17. P values less than 0.05 were considered statistically significant. Results: Mean serum creatinine was 1.7 mg/dl for Grade 1 (range: 1.1- 4.7 mg/dl, STD 0.44), 2.38 mg/dl for Grade 2 (range: 1.8-3.9 mg/dl STD 0.40), 4.18 mg/dl for Grade 3 (range: 2.6-6.0 mg/dl, STD 0.88), and 5.65 mg/dl for Grade 4 (range: 3.1-12 mg/dl, STD 2.0. Conclusion: Renal echogenicity and its grading correlates better with serum creatinine in CKD than other sonographic parameters. Hence, renal echogenicity is a better parameter than serum creatinine for estimating renal function in CKD, and has the added advantage of irreversibility.