Xin-Gui Peng1, Yuancheng Wang1, Shijun Zhang1, Yingying Bai1, Hui Mao2, Gao-Jun Teng1, Shenghong Ju1. 1. Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing, P.R. China. 2. Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia, USA.
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 T1 ρ magnetic resonance imaging (MRI). MATERIALS AND METHODS: In all, 18 rats and 70 humans were involved in this study. For the animal study, T1 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 T1 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 T1 ρ and age/gender/physical endurance were calculated. RESULTS: The average T1 ρ relaxation times of the TA and SOL of female rats were higher than that of male rats (P < 0.001). The T1 ρ relaxation time of TA was significantly lower compared to SOL (P < 0.001). A significant linear correlation was observed between T1 ρ and the type I slow-twitch fiber proportion (%) in SOL (R2 = 0.837, P < 0.001). Similarly, in human studies the average T1 ρ relaxation times of TA were significantly lower than SOL for all age groups (P < 0.001). The higher T1 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 T1 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 T1 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.
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 T1 ρ magnetic resonance imaging (MRI). MATERIALS AND METHODS: In all, 18 rats and 70 humans were involved in this study. For the animal study, T1 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 T1 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 T1 ρ and age/gender/physical endurance were calculated. RESULTS: The average T1 ρ relaxation times of the TA and SOL of female rats were higher than that of male rats (P < 0.001). The T1 ρ relaxation time of TA was significantly lower compared to SOL (P < 0.001). A significant linear correlation was observed between T1 ρ and the type I slow-twitch fiber proportion (%) in SOL (R2 = 0.837, P < 0.001). Similarly, in human studies the average T1 ρ relaxation times of TA were significantly lower than SOL for all age groups (P < 0.001). The higher T1 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 T1 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 T1 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.
Authors: Ryan Brown; Azadeh Sharafi; Jill M Slade; Antonio Convit; Nathan Davis; Steven Baete; Heather Milton; Kenneth J Mroczek; Patricia M Kluding; Ravinder R Regatte; Prodromos Parasoglou; Smita Rao Journal: BMJ Open Diabetes Res Care Date: 2021-09