Sound touch elastography for noninvasive assessment of renal fibrosis and chronic kidney disease progression: diagnostic accuracy and histopathological correlation.

AIM: The aim of this study was to evaluate the clinical utility of sound touch elastography (STE) in assessing renal cortical elasticity across different stages of chronic kidney disease (CKD) and its association with histopathological grading of interstitial fibrosisand tubular atrophy (IFTA).

MATERIALS AND

METHODS

All enrolled patients with clinically indicated renal biopsies for the diagnosis and monitoring of CKD, stratified across all five CKD stages based on estimated glomerular filtration rate (eGFR), underwent conventional B-mode ultrasound and STE examinations of the biopsied kidney, performed by an experienced sonographer blinded to clinical and histopathological data, to measure renal cortical elasticity parameters. Histopathological assessment of the biopsy samples served as the reference standard for IFTA grading.

RESULTS

All STE-derived elasticity parameters demonstrated progressive elevation with advancing CKD stages (P<.001), receiver operating characteristic (ROC) analysis demonstrated STEmean's superior diagnostic performance for advanced CKD vs early-stage CKD (area under the curve [AUC] = 0.90, 95% confidenceinterval [CI]: 0.85-0.95; sensitivity 70.5%, specificity: 92.7% at 12.7 kPa), outperforming renal dimensional parameters and inversely correlating with eGFR (r=-0.75, 95% CI: -0.81 to -0.66; P<.001). Similarly, STE values increased significantly with IFTA severity: mild IFTA (11.31 ± 2.42 kPa), moderate IFTA (13.85 ± 3.65 kPa), and severe IFTA (15.3 ± 3.19 kPa) (P<.001). STEmean demonstrated high accuracy in differentiating IFTA severity, with AUCs of 0.81 (95% CI: 0.74-0.88) for d0iscriminating mild from moderate to severe IFTA and 0.79 (95% CI: 0.72-0.87) for distinguishing mild to moderate from severe IFTA.

CONCLUSION

STE represents a reliable ultrasound-based method for evaluating CKD progression and tubulointerstitial fibrosis. The technique shows better diagnostic performance for CKD staging than for IFTA grading, suggesting its potential clinical utility in noninvasive renal assessment.