#613 Is there a relationship between kidney stiffness identified by 2D shear wave elastography and the estimated glomerular filtration rate?

Abstract Background and Aims Ultrasound-based elastography has been utilized as an imaging method with high utility in the liver or thyroid, but it is not yet being implemented in evaluating the chronic kidney disease (CKD) because current research indicates a high level of heterogeneity between studies. We aimed to investigate if there is a connection between kidney stiffness measured with a new, specially designed elastography software for kidneys and estimated glomerular filtration rate (eGFR). Method In 2022 and 2023 we performed a cross-sectional study in 150 participants (50 healthy, 50 kidney-transplanted, 50 with chronic glomerulonephritis). The mean value of five different measurements for each kidney were correlated with biological and clinical parameters. To examine the variations amongst the three groups, one-way between-groups ANOVA was employed. Results The mean kidney stiffness for the healthy cohort was 31.9 ± 2.9 kiloPascal (kPa), for kidney transplanted (Ktx) patients 25.9 ± 6.9 kPa and for the chronic glomerulonephritis (GN) 23.8 ± 7.45 kPa. We discovered correlations between kidney stiffness and eGFR in all three groups: healthy r = 0.61, p 0.0001, Ktx r = 0.56, p 0.0001, GN r = 0.70, p 0.0001. We also found a value of under 26 kPa for the detection of an eGFR under 60 mL/min/1.73 m2 with 94.3% sensitivity and 84% specificity (AUC = 0.905, p 0.0001). The healthy group showed significant higher values than Ktx or GN groups, but without significant differences between the latter two. Conclusion Our findings demonstrate a correlation between renal function, with very good diagnostic accuracy, and these novel imaging techniques. A decrease in renal stiffness with the progression of CKD could prove to be an easy, reproducible approach to provide additional diagnostic information. However, given the limited number of participants, additional studies are required before they can be incorporated into standard clinical practice.