A representative slice of an MTR image from two timepoints (left and middle) and a ΔMTR map (right). The ΔMTR map is obtained by taking the difference between the MTR images at timepoint 2 and timepoint 1. Two new MTR lesions (blue arrows) are evident at timepoint 2 but not at timepoint 1. One MTR lesion apparent at timepoint 1 (red arrow) has partially recovered by timepoint 2. MTR lesions with increasing and decreasing MTR are segmented using the ΔMTR map and are called ΔMTR lesions
One important area to investigate repair is to work out how it may be monitored. This study suggests one such imaging modality. Although changes in MTR may be a good indicator of changes in myelin, MTR change is not completely specific for myelin. As with any imaging technique, possible confounding effects should be considered. MTR changes rapidly at the time of lesion formation, making measurements in this period dependent on the phase of lesion formation/resolution at the time of imaging. However if it does represent remyelination it is a useful tool.