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Assessing the variability of 23 Na MRI in skeletal muscle tissue: Reproducibility and repeatability of tissue sodium concentration measurements in the lower leg at 3 T
Author(s) -
Gerhalter Teresa,
Gast Lena V.,
Marty Benjamin,
Uder Michael,
Carlier Pierre G.,
Nagel Armin M.
Publication year - 2020
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.4279
Subject(s) - repeatability , reproducibility , coefficient of variation , nuclear medicine , limits of agreement , muscle tissue , medicine , skeletal muscle , biomedical engineering , chemistry , anatomy , chromatography
The goal of this study was to evaluate the reproducibility and repeatability of tissue sodium concentration (TSC) measurements using 23 Na MRI in skeletal muscle tissue. 23 Na MRI was performed at 3 T on the right lower leg of eight healthy volunteers (aged 28 ± 4 years). The examinations were repeated at the same site after ~ 22 weeks to assess the variability over a medium‐term period. Additionally, they were scanned at a second site shortly before or shortly after the first visit (within 3 weeks) to evaluate the inter‐site reproducibility. Moreover, we analysed the effect of B 0 correction on the variability. Coefficients of variations (CVs) from mean TSC values as well as Bland–Altman plots were used to assess intra‐site repeatability and inter‐site reproducibility. In phantom measurements, the B 0 correction improved the quantitative accuracy. We observed differences of up to 4.9 mmol/L between the first and second visit and a difference of up to 3.7 mmol/L between the two different sites. The CV for the medium‐term repeatability was 15% and the reproducibility CV was 9%. The Bland–Altman plots indicated high agreement between the visits in all muscle regions. The systematic bias of −0.68 mmol/L between site X and Y ( P = 0.03) was slightly reduced to −0.64 mmol/L after B 0 correction ( P = 0.04). This work shows that TSC measurements in healthy skeletal muscle tissue can be performed with good repeatability and reproducibility, which is of importance for future longitudinal or multicentre studies.