Alex Bibbey MD, Presenter: Nothing to Disclose

P. Murali Doraiswamy MD, Abstract Co-Author: Research Consultant, Bristol-Myers Squibb Company Research Consultant, Eli Lilly and Company Research Consultant, Neuronetrix, Inc Research Consultant, Medivation, Inc Research Grant, Bristol-Myers Squibb Company Research Grant, Eli Lilly and Company Research Grant, Neuronetrix, Inc Research Grant, Medivation, Inc Stockholder, Sonexa Therapeutics, Inc Stockholder, Clarimedix, Inc Speaker, Forest Medical, LLC

Jeffrey Robert Petrella MD, Abstract Co-Author: Advisory Board, Johnson & Johnson Speakers Bureau, Quintiles Inc Advisory Board, Piramal Enterprises Limited

Jeffrey William Prescott MD, PhD, Abstract Co-Author: Nothing to Disclose

The hypothesis of the current study is that relationships between cortical amyloid burden as evaluated by florbetapir PET imaging and cognitive testing batteries may provide complementary information about pathologic changes in Alzheimer's Disease (AD).

Subjects were those newly enrolled in the ADNI2 study. Baseline data was used. T1 anatomical images were parcellated using FreeSurfer software. Parcellations were registered to florbetapir PET scans. Florbetapir SUVr for each parcellated cortical region of interest was calculated, using the whole cerebellum as the reference region. Clinical cognitive assessments included ADAS-Cog, MMSE, Rey AVLT, Boston Naming Test, Trail Making Test A and B, and the Clock Drawing Test. Statistical analyses were performed between amyloid status in selected cortical regions (superior, middle, and inferior temporal, entorhinal, precuneus, posterior cingulate, and superior frontal) as assessed by PET and clinical cognitive measures.

There were 102 ADNI2 subjects (64 males, 38 females, mean age 73.8 years) available at the time of the analysis. There were 37 normal control, 19 early mild cognitive impairment (MCI), 25 late MCI, and 21 AD subjects, representing a spectrum of clinical cognitive status. Regression modeling of florbetapir SUVr as a predictor of cognitive battery performance revealed the region with the most significant associations between cognitive performance and amyloid SUVr was the right precuneus, with ADAS-cog, MMSE, and Trail A test (p < 0.05). The cognitive test with the most association with regional florbetapir SUVr was ADAS-cog, with left entorhinal, left posterior cingulate, and right precuneus.

Significant associations between regional florbetapir PET SUVr and cognitive battery performance indices were noted mostly in the right precuneus, with the ADAS-cog cognitive test the most associated with SUVr across regions. It is thought that the rate of cognitive decline is greatest when the rate of amyloid accumulation has plateaued, and further increase is minimal. Ongoing longitudinal investigations will further evaluate how cognitive decline may be affected in the setting of increasing amyloid burden in asymptomatic subjects or those with mild cognitive impairment. 

Quantitative amyloid PET may provide information about global and local structural changes in AD, aiding in diagnosis and disease tracking. 

Bibbey, A, Doraiswamy, P, Petrella, J, Prescott, J, Relationships between Quantitative Amyloid Burden and Cognition in Alzheimer's Dementia.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013960.html