Aging effects on human calf muscle properties assessed by MRI at 3 Tesla

PURPOSE: To determine age-related changes in MR properties as T2 and T2* relaxation times, fat content, and magnetization transfer in the human calf, and comparison of these effects in different muscle groups. MATERIALS AND METHODS: Studies were performed on 12 "younger" (mean, 31.2 +/- 6.1 years) and 11 "older" healthy adult individuals (mean, 66.1 +/- 7.8 years). The tibialis anterior muscle, the soleus muscle and the gastrocnemius muscle were examined at rest in a 3 Tesla whole-body MR unit. T2 and T2*, muscular fat content and magnetization transfer ratios (MTR) were determined. Results of the two age groups were compared, and differences between the muscle groups were investigated. RESULTS: Increase of T2 and muscular fat was detected with age with significant difference between the age groups. The extent of fatty infiltration was much more variable for the "older" group. For both age groups, the tibialis anterior muscle showed the lowest fat content with 1.2 +/- 0.4% in the "young" group and 2.3 +/- 0.7% in the "older" group. A strong correlation between fat content and T2 was found, while the groups did not significantly differ regarding T2*. Decrease in the MTR could only be shown for the tibialis anterior muscle with age. CONCLUSION: Age-related changes in healthy human calf musculature were found. Further studies might show possible correlations of age-dependent changes with physical efficiency and susceptibility to diseases like type 2 diabetes.