"The Relation between Serum Creatinine and Renal Resistance Index in Parenchymal Kidney Disease"

Background/Objective: Considering the fact that gray-scale ultrasonography findings in patients with non-surgical kidney disease are highly non-specific, this study was conducted to evaluate the efficacy of color Doppler ultrasonography for determining a quick assessment of the renal function. In this study, the association between the kidney interlobar artery resistive index (RI) and serum creatinine level was investigated to identify whether this index has a significant relationship with the serum creatinine level. Patients and Methods: In a cross-sectional study, 30 patients with non-surgical parenchymal renal disease who had a serum creatinine level>1.4 mg/dL were selected during regular revisits. 30 normal individuals with serum creatinine levels<1.4 mg/dL were also selected as the comparison group. The kidneys of these subjects were investigated with gray-scale ultrasonography for bilateral symmetry, absence of stones, hydronephrosis, and any space occupying lesion. They were then evaluated with color Doppler ultrasonography and the RI was measured in 10 interlobar arteries (5 in each kidney). Results: The mean±SD serum creatinine level was 6.5±0.6 mg/dL in the case and 1.0±0.3 mg/dL in the control group. The mean RI was 78.0%±1.9% for the case and 59.3%±0.8% for the control group (p<0.001). A significant correlation was found between the serum creatinine level and the RI (r=0.68, p<0.001). Conclusion: In renal parenchymal disease, measuring RI by Doppler ultrasonography is a fair predictor of renal function.