Until recently, brain imaging has been of limited use in the diagnosis and treatment of Alzheimer’s Disease (AD). New research shows that brain imaging for AD may be on the verge of a breakthrough.
Currently, most diagnoses of AD are made clinically, i.e., based on a physician’s examination. Often the physician does not order brain imaging to make the diagnosis since it is a complicated, expensive test, and results do not affect treatment. However, if the brain scan provided useful clinical information about the diagnosis of AD (versus other types of dementia or memory loss), or prognosis (the predicted course of the disease), it could be very useful for the physician in determining the best treatment.
At the International Conference on Alzheimer’s Disease, research was presented showing that brain imaging using PET (positron emission tomography) and a chemical compound called florbetapir could provide useful information about both the diagnosis and prognosis of AD. [Florbetapir is a compound which binds to amyloid in the brain; amyloid plaques are found in the brains of people with AD.] A group of people with mild cognitive impairment (MCI) and normal cognition were injected with florbetapir and placed in the PET brain scanner. Six and twelve months later, the same individuals were reassessed for dementia severity and ability to function. The study found that of the MCI group, 38% were positive for large amounts of amyloid. Of this group (MCI + positive amyloid), 22% had progressed to AD. The study also found that the degree of florbetapir uptake corresponded with both dementia severity and greater functional impairment.
These findings suggest that PET scans could soon be used as a way to screen people for early, pre-clinical signs of AD. The PET scans could also be used to design new treatments for AD by:
1) seeing if the new treatments prevent amyloid build-up in the brain
2) seeing if less amyloid corresponds with less severe dementia and better functioning
Live Mentally Healthy,
Cognitive Psychiatry of Chapel Hill