Repeatability assessment of sodium (23Na) MRI at 7.0 T in healthy human calf muscle and preliminary results on tissue sodium concentrations in subjects with Addison's disease.

In BMC musculoskeletal disorders ; h5-index 46.0

OBJECTIVES : To determine the relaxation times of the sodium nucleus, and to investigate the repeatability of quantitative, in vivo TSC measurements using sodium magnetic resonance imaging (²³Na-MRI) in human skeletal muscle and explore the discriminatory value of the method by comparing TSCs between healthy subjects and patients with Addison's disease.

MATERIALS AND METHODS : In this prospective study, ten healthy subjects and five patients with Addison's disease were involved. ²³Na-MRI data sets were acquired using a density-adapted, three-dimensional radial projection reconstruction pulse sequence (DA-3DPR) with a modification for the relaxation times measurements. Differences in TSC between muscle groups and between healthy participants were analysed using a nonparametric Friedman ANOVA test. An interclass correlation coefficient (ICC) was used as the repeatability index. Wilcoxon rank sum test was used for evaluation of differences in TSC between study participants.

RESULTS : The mean T₁ in the gastrocnemius medialis (GM), the tibialis anterior (TA), and the soleus (S) was 25.9 ± 2.0 ms, 27.6 ± 2.0 ms, and 28.2 ± 2.0 ms, respectively. The mean short component of T₂^*, T₂^*_short were GM: 3.6 ± 2.0 ms; TA: 3.2 ± 0.5 ms; and S: 3.0 ± 1.0 ms, and the mean long component of T₂^*, T₂^*_long, were GM: 12.9 ± 0.9 ms; TA: 12.8 ± 0.7 ms; and S: 12.9 ± 2.0 ms, respectively. In healthy volunteers, TSC values in the GM were 19.9 ±0.1  mmol/L, 13.8 ±0.2 mmol/L in TA, and 12.6 ± 0.2 mmol/L in S, and were significantly different (p = 0.0005). The ICCs for GM, TA and S were 0.784, 0.818, 0.807, respectively. In patients with Addison's disease, TSC in GC, TA, and S were 10.2 ± 1.0 mmol/L, 8.4 ± 0.6 mmol/L, and 7.2 ± 0.1 mmol/L, respectively.

CONCLUSIONS : TSC quantification in a healthy subject's calf at 7.0 T is reliable; the technique is able to distinguish sodium level differences between muscles and between healthy subjects and Addison's disease patients.

Zaric Olgica, Beiglböck Hannes, Janacova Veronika, Szomolanyi Pavol, Wolf Peter, Krebs Michael, Trattnig Siegfried, Krššák Martin, Juras Vladimir

2022-Oct-20

Addison’s disease, Calf muscle, Sodium magnetic resonance imaging, Tissue sodium concentration