Comparison of sound touch elastography and quantification for assessing the renal pathologic changes in patients with proteinuria

Objective: Sound touch elastography (STE) and sound touch quantification (STQ) are novel imaging methods to evaluate tissue stiffness. This study aims to investigate renal stiffness in patients with chronic kidney disease (CKD) by STE and STQ, using renal biopsy as ‘gold standard’. Methods: Between 2019 January and 2022 June, 60 patients who underwent renal biopsy for proteinuria (cases) and 45 healthy volunteers (controls) at our hospital were included in this study. The maximum and mean elastic modulus (Emax, Emean) of region of interest in right kidney were measured by STE and STQ techniques. Biochemical profiles and renal biopsy findings were recorded. Results: Both Emax and Emean measured by STE were significantly different between cases and controls. ROC analysis of STE measurements revealed using a cutoff of 13.53 kPa for Emax and 10.16 kPa for Emean, the area under the curve (AUC) to distinguish nephropathy from healthy was 0.718 and 0.744. Analysis of ROC for STQ measurements showed that using a cutoff value of 15.87 kPa for Emax and 9.95 kPa for Emean, the AUC for the nephropathy was 0.612 and 0.569. Emax and Emean values were significantly different among CKD patients with mild, moderate and severe pathological stage. The Emax value for STE was positively related to Scr, β2-MG (r = 0.257, 0.292, p < 0.05). Conclusion: Both STE and STQ are non-invasive, feasible methods to quantitatively evaluate renal stiffness. STE is more effective than STQ in the diagnosis of CKD patients with proteinuria. Critical relevance statement: Sound touch elastography is more effective than sound touch quantification in the diagnosis of chronic kidney disease patients with proteinuria. Key points: • Emax and Emean measured by STE were different between cases and controls. • Emax and Emean were different among CKD patients with different pathological stages. • The Emax value for STE was positively related to serum creatinine, β2-microglobulin Graphical Abstract: [Figure not available: see fulltext.]