Renal ultrasound and Doppler parameters as markers of renal function and histopathological damage in children with chronic kidney disease.

Aim: Doppler ultrasonography can be used to assess the progression of vascular (arterial sclerosis) and parenchymal (glomerular sclerosis and crescents) renal damage. The aim of this study was to evaluate the significance of some sonographic and Doppler parameters as non-invasive markers of glomerular filtration rate (GFR) and renal histopathological damage in children.

Methods: A cohort of 84 children were enrolled in a case-control study (42 with CKD stages 2-5 and 42 healthy children). GFR was assessed using new improved equation using serum creatinine and cystatin C. Sonar guided renal specimen was obtained and evaluated for the severity of global sclerosis (GS), segmental sclerosis (SS), tubular atrophy (TA), interstitial fibrosis (IF), arterial sclerosis (AS) and arteriolar hyalinosis (AH). The following sonographic and Doppler parameters were assessed in both patients and control group: resistivity index (RI), pulsatility index (PI), atrophic index (AI), mean renal volume, mean renal density, time average velocity (TAV) and body surface area related volume perfusion (BSARVP).

Results: There was significant difference in renal density (P < 0.001), RI (P < 0.001), PI (P = 0.021), TAV (P < 0.001) and BSARVP (P < 0.001) between patients and control group. The cutoff value of RI was 63.5% (sensitivity 83% and specificity 64%). Multivariate analysis revealed that renal density and RI were significant predictors of worsening of estimated GFR (eGFR) in CKD patients.

Conclusion: Any increase in the RI and PI values must arouse alarm to the possibility of advancing renal damage. Moreover, RI and PI could fairly predict the degree of glomerular sclerosis and interstitial fibrosis.