Correlation of renal ultrasound parameters with chronic kidney disease stage

Renal ultrasound is a fundamental tool in nephrological practice due to its non-invasive nature, accessibility, and low cost. Although it is widely used for the initial diagnosis of kidney diseases, its role as a follow-up method in chronic kidney disease (CKD) is less frequent. This review explores the correlation between ultrasound parameters and CKD progression, considering that these may reflect kidney morphostructural changes. Several ultrasound parameters are analyzed: renal length adjusted for height and corrected parenchymal thickness show a significant association with estimated glomerular filtration rate (eGFR). In contrast, cortical thickness and renal width present limitations and show poor correlation with eGFR. Renal echogenicity, assessed against the liver and spleen, is related to irreversible renal damage and histological changes such as tubular atrophy and glomerulosclerosis, being one of the best ultrasound predictors of CKD progression. Of particular note is the CKD ultrasound score proposed by Yaprak, which integrates renal length, parenchymal thickness, and parenchymal echogenicity. This score has demonstrated high predictive ability to identify eGFR <60 ml/min, with an area under the curve of 0.829, sensitivity of 81%, and positive predictive value of 92%. Finally, intrarenal Doppler parameters are described. The resistive index (RI) and peak systolic velocity (PSV) correlate with renal histological damage. In conclusion, when appropriately applied and interpreted, renal ultrasound can provide valuable information for a more comprehensive assessment of CKD progression.