Limitations
There are some limitations in this study. First is the 4-year duration between the start of intervention and follow-up. Second is the fact that fewer participants completed follow-up MRI scans, partially due to early termination of the trial. Third is that the reported DTI and CBF measures did not show significance after multiple comparisons (possibly due to a higher noise-to-signal ratio in DTI and CBF compared with fluid-attenuated inversion recovery), and their interpretations should be considered exploratory. Increasing the sample size in future clinical trials would help in reaching statistical significance after correction for multiple comparisons for regional analyses in those modalities.