Introduction: Sodium hemostasis is altered in patients with chronic kidney disease (CKD) due to long term loading, and sodium (23Na) can be deposited in the skin, muscle and skeleton. We measured 23Na content in these tissues of CKD patients, using 23Na magnetic resonance (MR) imaging. Methods: This is a pilot cross-sectional study of CKD stage 4-5D patients and healthy controls. Subjects underwent a 23Na MR study of their right lower leg using a multinuclear-capable 3.0-T MRI. An axial proton T1-weighted fast-low-angle-shot sequence was acquired to delineate the anatomy; followed by a 23Na MR image obtained with a custom-made 23Na coil and sodium-optimized pulse sequences. Concentration maps were generated using saline solutions at different 23Na concentrations as calibration vials. Four regions of interest (ROIs) were drawn: 1) pre-tibial skin, 2) posterior leg skin, 3) tibia, and 4) soleus muscle. Baseline characteristics and blood samples were also collected. Results: 10 controls, 12 CKD and 23 dialysis (10 peritoneal dialysis (PD) and 13 hemodialysis (HD)) subjects participated in the study. 23Na concentration in all four tissues was significantly higher in dialysis patients compared to controls (p-value23Na of HD, PD and CKD groups. Tissue sodium levels correlated strongly with markers of mineral bone disease and inflammation. Associated factors appear to be tissue specific. Conclusion: Dialysis patients were found to have significantly higher 23Na level in their tissues compared to healthy controls. The effect and clinical utility of tissue 23Na remains to be studied.
Sodium MRI, non-osmotic sodium, tissue sodium, Chronic kidney disease, Hemodialysis, Peritoneal dialysis
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