Role of intrarenal resistive index and ElastPQ® renal shear modulus in early diagnosis and follow-up of diabetic nephropathy: A prospective study

Abstract

Introduction We aimed to establish baseline normal values of ElastPQ® (Philips Healthcare, Bothell, Washington, USA) renal shear modulus, evaluate changes in intrarenal resistive index and renal shear modulus in various stages of diabetic nephropathy, their diagnostic potential and role in follow-up. Methods Our prospective observational study was performed over two years. In total, 130 adult cases with diabetic nephropathy and 130 normal adult controls were selected. Diabetic nephropathy was confirmed by persistent albuminuria on 24-hour urinary albumin testing at three month intervals and staged by albuminuria quantification. Measurement of intrarenal resistive index and renal shear modulus in all subjects was performed and their variation with stage of nephropathy was statistically analyzed using Pearson’s correlation. Receiver operating characteristic curves were plotted and their individual and combined diagnostic potentials were assessed. Statistical significance was tested using t tests and analysis of variance. Interrater agreement was tested using Cohen’s kappa coefficient. Results Mean intrarenal resistive index was significantly higher for cases (mean 0.72 ± 0.05) than controls (mean 0.62 ± 0.04) and showed significant age variation (p < 0.05). Normal values of ElastPQ® renal shear modulus ranged from 3.87 to 4.72 kPa and was significantly higher for cases (mean 8.59 ± 1.77 kPa) than controls (mean 4.32 ± 0.45 kPa) and showed significant differences between each stage of nephropathy, being highest in stage 2. Maximum diagnostic accuracy was at 0.65 (sensitivity 90%, specificity 76.2%, area under curve 0.916) for intrarenal resistive index and at 5.31 kPa (sensitivity 90.8%, specificity 84.6%, area under curve 0.923) for renal shear modulus. Combination of the two further improved diagnostic performance (highest accuracy of 89%, sensitivity 81.7%, specificity 96.3%). Conclusions Normal range of ElastPQ® renal shear modulus values could be established. Intrarenal resistive index and renal shear modulus can be used as imaging parameters for early diagnosis and follow-up of diabetic nephropathy.

Current Insights into the Significance of the Renal Resistive Index in Kidney and Cardiovascular Disease

“…The RRI proved to be significantly higher in patients with diabetic kidney disease than in those with different chronic renal diseases [46][47][48]. In diabetic kidney disease, the RRI increases with the severity or progression of renal disease, as is the case in any other CKD [49][50][51][52][53].…”

Current Insights into Renal Resistive Index Significance in Kidney and Cardiovascular Disease

“…Diabetic Nephropathy. RRI proved to be significantly higher in patients with diabetic nephropathy than in those with different chronic renal diseases [47][48][49]. In diabetic nephropathy RRI is increasing with the severity or progression of renal disease, like in any other CKD [50][51][52][53][54].…”