Because of the location along the ventricles, the radiologist has suggested demyelinating disease as the cause. However MS is not the only condition that can cause lesions (hyperintense areas) in this area. At this point, your best help will be the neurologist when you see him/her.
Why was the imaging done? Generally the radiologist also says something along the lines of "correlate with clinical findings".
Sorry I'm not a lot of help here. It's tough to take an mri report out of context.