Ask The Expert: Can a Brain Scan Diagnose Alzheimer's? | Alzheimer's Prevention Registry

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April 20, 2016

Ask The Expert: Can a Brain Scan Diagnose Alzheimer's?

By Alzheimer's Prevention Bulletin


Dear Dr. Jagust,

I thought the only way to diagnosis Alzheimer’s disease definitively, unfortunately, is through an autopsy. Recently, a friend mentioned imaging studies, like PET scans, are being researched for this purpose. Can you explain the role of PET in diagnosing dementia? Will it replace the autopsy?


Dear Meg,

As an Alzheimer’s dementia researcher, I’m extremely enthusiastic about the emerging role of imaging in the study of brain imaging and dementia. At the Jagust Lab, I work with neuroscientists, radiochemists, physicists, engineers and computer scientists to develop and refine these imaging techniques, including PET. 

Additionally, as someone whose profession is dedicated to Alzheimer’s research and imaging, I’m always pleased to hear people outside of my profession are curious about the role of PET in Alzheimer’s dementia research.

Your friend is correct that PET imaging is being researched as a powerful tool to diagnose and stage Alzheimer’s disease. Recently, my team and I published a study that effectively demonstrates Alzheimer’s dementia staging using PET “in vivo” (within the living). This study also traced the role of beta amyloid and tau, two significant proteins that play a part in Alzheimer’s dementia.

Our study is excellent news for the potential of early diagnosis and staging of Alzheimer’s. It also helps us better understand the origins of Alzheimer’s dementia. However, I believe it’s still too early for PET scans to completely take the place of the examination of the brain following a death from Alzheimer’s. 

Why? While Alzheimer’s research has taken giant leaps forward in the past several years, there are still many unknowns, such as: 

  •  Are beta amyloid and tau only part of the Alzheimer’s dementia story?
  •  What processes in the brain are we unable to capture with PET and other imaging techniques?

Meg, thank you for your question. This is a topic that can be uncomfortable to discuss. I appreciate you giving me the opportunity to inform you and others about it.