I am 34 and have been having headaches for a year. After a normal CT and an MRI with 4-5 white spots (suspicious of MS but no symptoms), they have told me that my spots could have been a demyelinating event, an olod viral infection like Chicken Pox, normal spots, spots from migraines, etc etc. I don't have any answer from you because I am still in the same boat. basically a neurologist has had me on the MRi checkup/workup for MS for the past year and nothing has changed.
I'm sorry to hear about your daughter. Have you tried asking about your daughter's white spots on the MS forum. They may have more information.
I wish I had more advice. You and your daughter will be in my thoughts and prayers.