Evaluating the added value of multiparametric functional MRI in predicting renal function response to renal artery stenting in severe atherosclerotic renal artery stenosis

Objective: To explore the potential of Intravoxel Incoherent Motion Diffusion (IVIM) and Arterial Spin Labeling (ASL) in predicting the short-term effectiveness of post-revascularization for severe atherosclerotic renal artery stenosis.

Material and methods: A retrospective analysis of 88 cases from October 2018 to February 2023 was conducted. Patients were divided into Responder and Non-Responder groups based on renal function outcomes at their last follow-up. Clinical data were compared between the groups, and preoperative functional MRI images were analyzed. ROIs were outlined for the affected and both kidneys. Measurements included ASL-derived renal blood flow (RBF), IVIM's pseudo-diffusion coefficient (D*), perfusion fraction (f), true diffusion coefficient (D), and the conventional apparent diffusion coefficient (ADC).Multivariate logistic regression identified independent clinical predictors of benefit, and a clinical prediction model was developed. Model performance was assessed using Receiver Operating Characteristic (ROC) curves and Decision Curve Analysis(DCA) curves.

Results: In the training cohort of 54 non-responders and 34 responders, no quantitative parameters of bilateral kidneys showed statistical significance in predicting Responders (all p > 0.05). Pre-treatment eGFR, presence of diabetes, and the D value of the affected kidney were identified as independent factors for predicting short-term treatment effectiveness. The combined clinical-functional imaging model yielded the higher AUC at 0.796 (95 % CI: 0.690-0.897) . Decision curve analysis further confirmed the better net benefit of combined model.

Conclusion: Beyond clinical characteristics, functional MRI had the potential to predict response of stenting for severe atherosclerotic renal artery stenosis.