I'm sorry I do not know the answer to your question so this post should bump you to the top. Hopefully, someone who knows the answer to your question will come along and help you out.
Ren
I'm not sure what you mean by done on T1 not T2. MRIs are done on 1 Tesla, 1.5 Tesla or 3Tesla machines. The studies have sequences called T1, T2W, T2*, FLAIR, PD, STIR, etc. Demyelinaing lesions show up on T2, FLAIR, PD and STIR sequences. After GAD contrast, lesions may show up on T1 sequences if they are less than about 40 days old.
If you have lesions showing up on T1 post-GAD, these are active lesions. It might be best to post the actual radiologists reports. There are several nuances to understanding what the actual reports really mean.
Bob