PurposeWe aimed to investigate the relation between renal cortical stiffness (CS) obtained by shear-wave elastography (SWE) and contrast-induced nephropathy (CIN) development in interventional treatment-planned acute coronary syndrome (ACS) patients.MethodsOur study group consisted of 465 ACS patients. Routine laboratory assessments, B-mode, Doppler, and SWE renal ultrasonography (USG) evaluations were performed. Renal resistive index (RRI), renal pulsatility index (RPI), and acceleration time (AT) and CS were measured. Patients were grouped as with and without CIN.ResultsAmong the study group, 55 patients (11.8%) had CIN. Age, diabetes mellitus (DM), hypertension (HT), basal creatinine, CK-MB and troponin I levels, contrast volume, contrast volume/weight ratio, SYNTAX score, RRI, RPI, AT, and CS values were significantly higher in patients with CIN. eGFR was lower in patients who developed CIN. Age, contrast volume/weight ratio, and CS were determined as independent predictors of CIN occurrence in logistic regression analysis. In multivariate logistic analysis, increase of age (each year), contrast volume/weight (each 0.2mL/kg), and CS (each 1kPa) were found to augment the development of CIN by 7.1, 59.5, and 62.3%, respectively. In the ROC analysis, CS had the highest AUROC value. The cutoff value of CS obtained by the ROC curve analysis was 7kPa for the CIN development (sensitivity: 74.5%, specificity: 72.5%).ConclusionCS value is a simple, cheap, reproducible, noninvasive, and objective parameter for the detection of CIN development. ACS patients should be directed to renal USG, and routine CS value should be written besides USG measurements in reports.