Shear wave elastography imaging for assessing the chronic pathologic changes in advanced diabetic kidney disease

Kamal Hassan,1,2 Norman Loberant,3 Nur Abbas,4 Hassan Fadi,5 Hassan Shadia,5 Khaled Khazim2 1Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, 2Department of Nephrology and Hypertension, Peritoneal Dialysis Unit – Galilee Medical Center, 3Department of Radiology, Galilee Medical Center, Nahariya, 4The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 5Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Objective: The assessment of the grade of renal fibrosis in diabetic kidney disease (DKD) requires renal biopsy, which may be associated with certain risks. To assess the severity of chronic pathologic changes in DKD, we performed a quantitative analysis of renal parenchymal stiffness in advanced DKD, using shear wave elastography (SWE) imaging. Patients and methods: Twenty-nine diabetic patients with chronic kidney disease (CKD) grades 3–4 due to DKD, and 23 healthy subjects were enrolled. Combined conventional ultrasound and SWE imaging were performed on all participants. The length, width, and cortical thickness and stiffness were recorded for each kidney. Results: Cortical thickness was lower in patients with DKD than in healthy subjects (13.8±2.2 vs 14.8±1.6 mm; P=0.002) and in DKD patients with CKD grade 4 than in those with grade 3 (13.0±3.5 vs 14.7±2.1 mm; P<0.001). Cortical stiffness was greater in patients with DKD than in healthy subjects (23.72±14.33 vs 9.02±2.42 kPa; P<0.001), in DKD patients with CKD grade 4 than in those with grade 3 (30.4±16.2 vs 14.6±8.1 kPa; P<0.001), and in DKD patients with CKD grade 3b, than in those with CKD grade 3a (15.7±6.7 vs 11.0±4.2 kPa; P=0.03). Daily proteinuria was higher in DKD patients with CKD grade 4 than in those with grade 3 (5.52±0.96 vs 1.13±0.72; P=0.001), and in DKD patients with CKD grade 3b, than in those with CKD grade 3a (1.59±0.59 vs 0.77±0.48; P<0.001). Cortical stiffness was inversely correlated with the estimated glomerular filtration rate (r=-0.65, P<0.001) and with cortical thickness (r=-0.43, P<0.001) in patients with DKD. Conclusions: In patients with advanced DKD, SWE imaging may be utilized as a simple and practical method for quantitative evaluation of the chronic morphological changes and for the differentiation between CKD grades. Keywords: diabetic kidney disease, shear wave, elastography, cortical stiffnes