Abstract T MP118: Microinfarct Disruption of Cerebral White Matter: A Longitudinal Diffusion Tractography Analysis
Introduction: Cerebral microinfarcts (CMI) are associated with cognitive decline in clinico-pathological studies. Acute CMI can be detected by diffusion-weighted imaging (DWI). We prospectively evaluated the effect of incidental CMI on white matter (WM) ultrastructure using longitudinal diffusion tensor imaging (DTI)-based tractography.
Methods: Nine incidental DWI lesions were identified in six subjects (all males, age 67±9 years, mean pre-to-post lesional scan interval 19±4 months). All patients were diagnosed with probable cerebral amyloid angiopathy and underwent at least three MRIs as part of a prospective study. Silent DWI lesions were observed on the middle scan, enabling longitudinal analysis. Control regions-of-interest (ROIs) were generated in the contralateral hemisphere using semi-automated coregistration, and the lesion/control ROIs were coregistered to the pre- and post-lesional scans. DTI parameters [fractional anisotropy (FA); mean diffusivity (MD)] were measured within each ROI, along a short-segment of WM fiber tracts (within 6mm of the ROI), and along the entire tract. For the lesional scan, we compared DTI parameters between lesion and control ROIs. For the longitudinal analysis, we compared the ratio of lesion-to-control FA and MD at the pre-lesional and post-lesional scans.
Results: On the lesional scan, FA within the lesion ROI was significantly lower than in the control ROI (0.28±0.13 vs. 0.40±0.20, p=0.04) and MD was non-significantly reduced in the lesion ROI versus the control ROI (p=0.09). A significant decline within lesion ROI in FA ratio (1.22±0.45 vs. 0.91±0.439, p=0.04) and an increase in MD ratio (0.96±0.14 vs. 1.25±0.37, p=0.02) were observed between the pre-lesional and post-lesional scans. There was no difference in FA ratio or MD ratio for the short segment or entire tracts at the time of the lesion and in the longitudinal analysis.
Conclusion: We demonstrate persistent microstructural alterations of WM caused by incidental DWI lesions. Although these alterations do not extend outside the lesional ROI to associated fiber tracts, their accumulation over time may explain their association with cognitive decline.
Author Disclosures: E. Auriel: None. Y. Reijmar: None. B. Edlow: None. P. Fotiadis: None. S. Martinez-Ramirez: None. N. Jun: None. A. Reed: None. A. Vashkevich: None. K. Schwab: None. A. Viswanathan: None. M. Gurol: None. S. Greenberg: Research Grant; Significant; NIH 5R01NS059727.
- © 2014 by American Heart Association, Inc.