Poster C94, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Using functional magnetic resonance imaging to guide positron emission tomography analyses in mild cognitive impairment.
Shaina L. Garrison1, Chris M. Foster2, Daniel Kaufer1, Kathleen Welsh-Bohmer3, David Lalush1,4, Kelly S. Giovanello1; 1University of North Carolina at Chapel Hill, 2University of Texas at Dallas, 3Duke University, 4North Carolina State University
The current study compared metabolic activity between individuals with mild cognitive impairment (MCI) and age-matched healthy controls within functionally-defined Alzheimer’s disease (AD)-signature regions. Participants engaged in associative encoding, and then subsequent associative recognition, while undergoing simultaneous acquisition of fluorodeoxyglucose-positron emission tomography (FDG-PET) and BOLD functional magnetic resonance imaging (fMRI) using a Siemens 3T Biograph scanner. At encoding, participants learned a series of word pairs, either by creating a sentence that included both words or reading a provided sentence. At retrieval, associative recognition memory for the word pairs was assessed. Analysis of the task-based fMRI data revealed that participants with MCI showed greater encoding-related activity in the right middle frontal gyrus and right precuneus, than did control participants. Group differences in metabolic activity were assessed by comparing FDG standardized uptake values (SUVs) between groups, within these functionally defined regions. Results indicated that participants with MCI showed less metabolic activity than control participants in the same regions where they demonstrated functional hyperactivity. These findings provide novel insight into functional neural change associated with MCI. The results also demonstrate differential effects of MCI on task-based functional activity and glucose metabolism in the brain. To our knowledge, this study represents the first investigation to acquire simultaneous multi-modal imaging with the goal of using task-based fMRI to guide analysis of FDG-PET data.
Topic Area: LONG-TERM MEMORY: Development & aging