Prospective quantitative study: Doppler ultrasound in the evaluation of chronic renal allograft disease and correlation with histopathological finding

Abstract

Background and Objectives: Renal allograft biopsy is the gold standard for diagnosing chronic allograft nephropathy, but noninvasive methods are needed to avoid unnecessary biopsies. Doppler ultrasonography, particularly the resistive index (RI), correlates with renal allograft dysfunction. This study aims to assess the relationship between renal sonographic parameters and biochemical parameters in diagnosing graft interstitial fibrosis. Methods: The study evaluated 60 renal allograft recipients for sonographic renal morphological features and Doppler indices. The estimated glomerular filtration rate (eGFR) was calculated, and cortical fibrosis after the biopsy was determined using the Banff score. Continuous variables like mean and SD were calculated, and categorical variables were reported using frequencies and proportions. Associations were examined using independent sample t-tests, χ 2tests, and multivariate regression analysis. Results: The mean eGFR was 75.23±25.45 ml/min/1.73 m2. A significant correlation of eGFR with RI (r=0.341, P=0.008) was seen. A significant difference in mean RI (F=10.167; df=2,57; P<0.001) was seen among the histological grades of fibrosis. Among the histological grades of fibrosis, significant differences in RI among mild and moderate (S.E. 0.033, P=0.043), mild and severe (S.E. 0.026, P=0.001) as well as moderate and severe (S.E. 0.036, P=0.029) was seen. Conclusion: Doppler was able to noninvasively predict allograft fibrosis and could be used as a complementary imaging tool during the follow-up of renal allograft patients. Future research is needed to improve evidence, diagnostic criteria, guidelines, and long-term impact.