Comparison of short and long TR Gradient Recalled Echo (GRE) measures for total sodium concentration mapping in the calf

Sodium (23Na) MRI measures of tissue are SNR limited. Here, we compare a 3D gradient recalled echo (GRE) 23Na scans with a short TR and fully recovered TR for estimation of tissue sodium concentration (TSC) in the calf. We validate measures by collecting 23Na T1 measures of the calf and reference bottles. A short TR scan is shown to provide increased image SNR, resulting in higher measures of TSC, along with improved depiction of the skin. Using the short TR GRE scan, older subjects and haemodialysis patients are shown to have higher calf TSC than younger subjects.