The value of sound touch elastography in the noninvasive staging of fibrosis in IgA nephropathy

To investigate the value of Sound Touch Elastography (STE) in fibrosis grading of IgA Nephropathy (IgAN), focusing on the diagnostic performance of the mean elasticity (STEmean) alone and combined with conventional ultrasound parameters. A total of 129 biopsy-proven IgAN patients underwent renal conventional ultrasound and STE.Based on the Oxford MEST-C T-score(reflecting the percentage of tubular atrophy/interstitial fibrosis area), patients were classified as T0 (≤ 25%), T1 (26–50%), and T2 (> 50%). Non-parametric tests were used to compare intergroup differences, correlations and diagnostic performance were assessed by Spearman and receiver operating characteristic (ROC) analyses. STEmean correlated significantly with T-score (r = 0.61, P < 0.001), eGFR (r = − 0.71, P < 0.001), and Scr (r = 0.67, P < 0.001). STEmean differed significantly across T0, T1, and T2 groups, as well as between S0 and S1 groups (all P < 0.001). Within-session measurement reliability was excellent (ICC = 0.990, 95% CI: 0.988–0.993). The combined model integrating STEmean and renal length (RL) achieved an AUC of 0.863 (95% CI: 0.795–0.932) for discriminating T0 from T1–2 and 0.826 (95% CI: 0.751–0.901) for discriminating T2 from T0–1, outperforming STEmean alone. This model provided high specificity (92.9%) and PPV (95.1%) for ruling in fibrosis, and high sensitivity (87.0%) and NPV (88.1%) for excluding severe fibrosis. STEmean, particularly when combined with renal length, demonstrated good diagnostic performance for the noninvasive assessment of renal fibrosis severity in IgA nephropathy, especially for identifying significant (≥ T1) and severe (T2) fibrosis. The distinction between adjacent moderate and severe fibrosis stages remains challenging, and the proposed thresholds require external validation. These findings support the potential role of STE as a noninvasive tool to complement fibrosis evaluation in IgAN.