The Diagnostic Role of Shear Wave Elastography and Renal Resistive Index in Diabetic Patients With and Without Chronic Kidney Disease: A Cross-Sectional Observational Study

Background and objective Diabetic kidney disease (DKD) is among the most common and serious complications of diabetes mellitus and is a major cause of chronic kidney disease (CKD) worldwide. Conventional biochemical markers such as serum creatinine, estimated glomerular filtration rate (eGFR), and albumin-creatinine ratio (ACR) primarily reflect functional impairment and may fail to detect early structural renal changes. Shear wave elastography (SWE) and renal resistive index (RRI) are emerging non-invasive imaging modalities that may help in the early identification of renal fibrosis and vascular alterations in diabetic nephropathy. The present study aimed to evaluate and compare SWE and RRI findings in diabetic patients with and without CKD and to assess their correlation with conventional renal function parameters. Methods This cross-sectional analytical observational study was conducted in the Department of Radiodiagnosis at Maharishi Markandeshwar Institute of Medical Sciences and Research, Mullana, Ambala, from April 2025 to March 2026. A total of 150 diabetic patients were enrolled, including 75 patients with clinically proven CKD and 75 diabetic patients without CKD who served as controls. Clinical and laboratory parameters, including serum creatinine, eGFR, ACR, and BMI, were recorded. Ultrasonography, Doppler evaluation, and SWE of both kidneys were performed using a Philips EPIQ-7 GI ultrasound machine (Philips Healthcare, Best, the Netherlands). Mean SWE values were recorded in kilopascals (kPa), while RRI was assessed using Doppler ultrasonography. Results A total of 150 diabetic patients were enrolled, including 75 with CKD and 75 without CKD. The groups were comparable in age (59.19 ± 7.95 vs. 58.80 ± 8.58 years; p = 0.775), sex distribution (49 (65.3%) males vs. 45 (60.0%) males; p = 0.613), and BMI (24.36 ± 3.03 vs. 23.58 ± 3.21 kg/m²; p = 0.130). Patients with CKD had significantly lower eGFR (59.92 ± 36.08 vs. 111.52 ± 12.72 ml/min/1.73 m²; p < 0.001) and higher serum creatinine (2.63 ± 1.37 vs. 1.36 ± 0.46 mg/dl), ACR (201.17 ± 214.51 vs. 11.57 ± 7.57 mg/g), RRI (0.69 ± 0.07 vs. 0.51 ± 0.10), and SWE values (11.19 ± 2.82 vs. 8.31 ± 0.82 kPa) (all p < 0.001). Among CKD patients, 20 (26.7%) were in Stage 1 and 20 (26.7%) in Stage 2, 10 (13.3%) in Stage 3, 15 (20.0%) in Stage 4, and 10 (13.3%) in Stage 5. SWE showed a strong negative correlation with eGFR (r = -0.777) and a positive correlation with ACR (r = 0.791) (both p < 0.001). RRI demonstrated an area under the curve (AUC) of 0.924 with 72% sensitivity and 100% specificity, while SWE showed an AUC of 0.899 with 100% sensitivity and 68% specificity for predicting CKD. Conclusions SWE and RRI are valuable non-invasive imaging biomarkers for the assessment of DKD. Both parameters showed a significant association with renal dysfunction and CKD severity. SWE demonstrated high sensitivity, while RRI demonstrated high specificity for identifying CKD. These modalities may serve as useful non-invasive adjuncts for assessment and risk stratification in diabetic patients. Further longitudinal studies are required to establish their role in early detection, monitoring, and prognostic evaluation.