Utility of shear wave elastography in evaluation of children with chronic kidney disease.

Background: Shear wave elastography (SWE) is proven for liver fibrosis. However, there are challenges in assessing the kidney owing to its surrounding structures, retroperitoneal location, and visceral fat. Kidney biopsy is the gold standard for estimating fibrosis, but is associated with inherent risks of bleeding and sedation. This study explores SWE's potential in assessing kidney fibrosis in CKD.

Methods: A total of 160 children < 18 years old with CKD or those undergoing kidney biopsy were enrolled from June 2022 to June 2024 in a cross-sectional study. SWE on a Philips Epic Elite system provided Young's modulus (YM) values. We analysed SWE with estimated glomerular filtration rate (eGFR, (CKD stages)) and urine protein creatinine ratio, in patients with CKD. Forty-one patients who underwent kidney biopsy were assessed for interstitial fibrosis and tubular atrophy (IFTA) and SWE.

Results: There was no relation between CKD stages, GFR, or proteinuria with YM/SWE. YM/SWE poorly predicted CKD with eGFR < 60 ml/min/1.73 m² (left kidney, 8 kPa (sensitivity 53.57%, specificity 65.62%, AUC 0.5), and right kidney, 9 kPa (sensitivity 57.14%, specificity 50%, AUC 0.39)). YM had fair diagnostic utility (AUC = 0.7) in detecting > 50% fibrosis in right kidney (11 kPa) and left kidney (6 kPa) (right side 75% sensitivity, 80% specificity, left side 100% sensitivity, and 31.43% specificity). Significant differences were noted in YM between right and left side (p = 0.013).

Conclusions: SWE was limited in differentiating CKD stages but could predict fibrosis over 50%. SWE might be helpful in identifying increasing fibrosis, but it is not useful in detecting early fibrosis or chronicity.