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Noninvasive assessment of age, gender, and exercise effects on skeletal muscle: Initial experience with T 1 ρ MRI of calf muscle
Author(s) -
Peng XinGui,
Wang Yuancheng,
Zhang Shijun,
Bai Yingying,
Mao Hui,
Teng GaoJun,
Ju Shenghong
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25546
Subject(s) - analysis of variance , medicine , magnetic resonance imaging , relaxation (psychology) , muscle relaxation , skeletal muscle , correlation , nuclear medicine , radiology , geometry , mathematics
Purpose To prospectively investigate age‐ and gender‐related changes in the fast‐twitch (tibialis anterior, TA) and slow‐twitch (soleus, SOL) skeletal muscle of healthy rats and volunteers and to compare the exercise‐related difference in health volunteers with T 1 ρ magnetic resonance imaging (MRI). Materials and Methods In all, 18 rats and 70 humans were involved in this study. For the animal study, T 1 ρ relaxation times were measured in the TA and SOL rat muscle with a 3.0T MRI scanner and compared to histological data. For the human study, three groups (young, middle‐aged, and elderly) of volunteers underwent T 1 ρ MRI scans (3.0T) of their calves. To further differentiate the human scans, 18 volunteers were recruited, half of them ( n = 9) routinely trained with high‐intensity sports, while the other half ( n = 9) with no physical training. Statistical analysis was performed via paired t ‐test, independent‐sample t ‐test, and analysis of variance (ANOVA). Correlations between T 1 ρ and age/gender/physical endurance were calculated. Results The average T 1 ρ relaxation times of the TA and SOL of female rats were higher than that of male rats ( P < 0.001). The T 1 ρ relaxation time of TA was significantly lower compared to SOL ( P < 0.001). A significant linear correlation was observed between T 1 ρ and the type I slow‐twitch fiber proportion (%) in SOL ( R 2 = 0.837, P < 0.001). Similarly, in human studies the average T 1 ρ relaxation times of TA were significantly lower than SOL for all age groups ( P < 0.001). The higher T 1 ρ relaxation times of TA and SOL in the elderly volunteers ( P < 0.001) and in the females ( P < 0.05) indicated significant age‐ and gender‐dependent differences. In high‐intensity sports groups, the higher T 1 ρ in SOL ( P < 0.01) and lower in TA ( P < 0.05) were observed compared with the control group. Conclusion This study demonstrated that T 1 ρ MRI can be used to display the differences in fast‐ and slow‐twitch skeletal muscle as well as potentially age‐, gender‐, and exercise‐related differences. Level of Evidence: 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:61–70