PET staging charts illustrate Alzheimer's progression, amyloid development

Alzheimer's includes certain mysteries that neurologists have yet solved. But a new study that tracks the progression of amyloid development and growth in the brain may be a step in the right direction.  

A new study conducted by a team of researchers led by Michel Grothe of the German Center for Neurodegenerative Diseases in Rostock, Germany, announced the development of a four-stage model of regional amyloid beta (Aβ) protein deposition that can be found in patients with Alzheimer's, according to an article by Alzforum. 

“This study opens exciting new avenues for future research, and further points to the pressing question of what it means to have amyloid in the brain, especially in the earliest stages of Aβ accumulation,” said Gaël Chételat of the University of Caen-Normandie in France and Melissa Murray of the Mayo Clinic in Jacksonville, Florida.  

This staging model was based on Florbetapir-PET scans. Grothe and his team's overarching hypothesis of the study was that distinct changes in the distribution of Aβ would correlate with the progression of the Alzheimer's.  

Imaging data from more than 700 volunteers in the Alzheimer's Disease Neuroimaging Initiative (ADNI) were analyzed. Roughly 179 of those PET scans were from cognitively normal people in the ADNI cohort.  

Grothe and his team were able to determine from this data and their four-stage model that the spatial distribution of Aβ plaques consistently changed as Alzheimer's progressed in the volunteers' brains.

"First appearing in the basal part of the temporal lobe, the anterior cingulate gyrus, and the bottom of the parietal lobe, then sweeping throughout the neocortex and eventually inward, overtaking subcortical regions such as the striatum," according to the article. Additionally, about half of the 179 cognitively normal people were found to have had Aβ deposition in various areas of the neocortex.  

Overall, Grothe and his team concluded that:  

  • Florbetapir PET reveals a four-stage model of regional amyloid deposition. 
  • Scans from 98 percent of people along the AD spectrum fit the scheme. 
  • Stages correlated with CSF Aβ42, clinical disease stage, and memory scores.