A CT scan might show some shrinkage. It might reveal a brain tumor. In the early stages it might show nothing abnormal. This is true of MRI and PET scans, even though they can reveal more about brain problems. It isn't unusual in early to middle stages of dementia for all scans to not reveal problems.

Be sure that the scan is read directly by a neurologist with dementia expertise. Radiologists can often miss subtle signs of dementia, especially if they aren't looking for it.