Work

Noninvasive assessment of age, gender, and exercise effects on skeletal muscle: Initial experience withT1ρ MRI of calf muscle

Year: 2016

Type: article

Abstract: 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 T1ρ magnetic resonance imaging (MRI). Materials and Methods In all, 18 rats and 70 humans were involved in this study. For the animal study, T1ρ 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 T1ρ 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 T1ρ and age/gender/physical endurance were calculated. Results The average T1ρ relaxation times of the TA and SOL of female rats were higher than that of male rats (P < 0.001). The T1ρ relaxation time of TA was significantly lower compared to SOL (P < 0.001). A significant linear correlation was observed between T1ρ and the type I slow-twitch fiber proportion (%) in SOL (R2 = 0.837, P < 0.001). Similarly, in human studies the average T1ρ relaxation times of TA were significantly lower than SOL for all age groups (P < 0.001). The higher T1ρ 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 T1ρ in SOL (P < 0.01) and lower in TA (P < 0.05) were observed compared with the control group. Conclusion This study demonstrated that T1ρ 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

Source: Journal of Magnetic Resonance Imaging

DOI: 10.1002/jmri.25546