Zhigang Qi, Presenter: Nothing to Disclose

Kun Cheng Li MD, Abstract Co-Author: Nothing to Disclose

Mild cognitive impairment(MCI) is the transitional continuum from normal aging to Alzheimer’s disease(AD) with heterogeneity. Our study is to evaluate the changes of default mode network in amnestic MCI(aMCI) patients.

Two groups including fourteen normal aging and fourteen aMCI patients were enrolled in this study and performed with resting-state fMRI. Demographics of the aMCI patients and normal aging including age, sex, and education years were matched between the two groups. Combined independent component analysis and seed-based functional connectivity were used to evaluate the default mode network of aMCI.

Default mode network in normal aging comprised a distributed set of regions that includes bilateral lateral PFC, ventral medial PFC/ACC, dorsal medial PFC/ACC, middle temporal gyrus, IPL, precuneus/PCC/retrosplenial cortex, fusiform gyrus, entorhinal cortex with additional regions as right HC and right medial dorsal thalamic nucleus(MD)/pulvinar. Compared to normal aging, decreased activation was observed in bilateral precuneus/PCC and right IPL, and no activation observed in bilateral entorhinal cortex, retrosplenial cortex, fusiform gyrus, and right HC in aMCI patients. Meanwhile, increased activation in left PFC, left IPL, and bilateral middle temporal gyrus was also observed in aMCI patients. Activation in MD/pulvinar shifted from right side in normal aging to left side in aMCI patients. A set of regions, including left lateral PFC, ventral/dorsal medial PFC, showed increased connectivity to the left MD/pulvinar in the aMCI patients. Whereas, decreased functional connectivity was observed between right MD/pulvinar and right lateral PFC.

In this study, we could propose that impaired default mode network function may be a biomarker for the diagnosis of amnestic MCI patients. Increased left frontoparietal activity and changes in functional connectivity between medial dorsal thalamic nucleus/pulvinar and PFC may indicate a compensatory process happened in amnestic MCI.

Resting-state fMR can be used as a method in the diagnosis of individuals at risk for AD.

Qi, Z, Li, K, Impairment and Compensation Coexist in the Default Mode Network of Mild Cognitive Impairment.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8010020.html