DIAGNOSTICS AND TECHNIQUES: Edited by Maarten W. TaalSodium MRI a new frontier in imaging in nephrologyFrancis, Susana; Buchanan, Charlotte E.a; Prestwich, Bena; Taal, Maarten W.bAuthor Information aSir Peter Mansfield Imaging Centre, School of Physics and Astronomy bCentre for Kidney Research and Innovation, Division of Medical Sciences and Graduate Entry Medicine, University of Nottingham, Nottingham, United Kingdom Correspondence to Professor Susan Francis, PhD, Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom. Tel: +44 115 8466518; e-mail: email@example.com Current Opinion in Nephrology and Hypertension: November 2017 - Volume 26 - Issue 6 - p 435-441 doi: 10.1097/MNH.0000000000000370 Buy Metrics Abstract Purpose of review This review focuses on the recent technological advances in quantitative sodium (23Na) MRI to provide a noninvasive measure of tissue viability for use in clinical studies of patients with kidney disease. 23Na MRI is the only noninvasive imaging technique that allows for the absolute spatial quantification of tissue sodium concentration (TSC), providing assessment of the corticomedullary sodium gradient (CMSG) in the kidney, and allowing measures of TSC in the skin and muscle. Recent findings 23Na MRI of the kidney has demonstrated the sensitivity to measure the CMSG, providing the normal range in healthy individuals and demonstrating a reduction in CMSG in kidney disease and transplanted kidneys. Studies using 23Na and 1H MRI have shown that in humans, skeletal muscle and skin can store sodium without water retention, and that sodium concentrations in muscle and skin increase with advancing age. Recent studies have shown that TSC can be mobilised during haemodialysis, and that skin sodium content links closely to left ventricular mass in patients with chronic kidney disease. Summary 23Na MRI is currently a research technique, but with future advances, 23Na MRI has potential to become a noninvasive renal biomarker and a measure of tissue sodium storage for clinical studies. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.