I was just browsing, first time on the site. I am currently undergoing work up for MS... but I wanted to say that I work in a doctor's office and I frequently see the mri results that show non-specific white matter.
They use that because they do not want to specifically state what the reason for the white matter, or lesions is. They expect the doctor to combine this with the clinical information and other studies before committing to a diagnosis. If a diagnosis of MS is already documented and well known in the MRI records, they will then note the lesions as being MS related. Sometimes, they will state in a report that non-specific lesions or white matter is seen that may be consistent with a demylienating process.
It's all doctor speak for we won't tell you it's MS until we know for sure without a doubt (or written on our foreheads)lest you sue us....
Good luck to you and your husband, I can understand your fear, and worry. I've been going through it too.