Altered white matter integrity and functional connectivity of hyperacute-stage cerebral ischemia in a rat model.
Ischemic stroke is accompanied by structural deformation and functional deficits in the affected hemisphere. Within a couple of hours after symptom onset, the accurate identification of brain characteristics is critical to design the therapeutic strategies and it can potentially improve overall brain tissue viability by minimizing irreversible brain damage. In this study, white matter integrity and functional connectivity within 2-4h after right middle cerebral artery occlusion in rats were investigated using multimodal magnetic resonance imaging. During this stage, diffusion tensor image (DTI) revealed that fractional anisotropy along the ipsilesional external capsule was slightly increased as compared with preoperative baseline. Resting state functional MRI (rs-fMRI) showed that the inter-hemispheric functional connectivities from primary motor (M1), primary somatosensory of forelimb (S1FL), and barrel field (S1BF) seeds were considerably reduced at the hyperacute stage. Fractional amplitudes of low frequency fluctuations (fALFF) from rs-fMRI were significantly enhanced at the hyperacute stage in the frequency spectrum between 0.01 and 0.08Hz. In addition, the changes in fALFF were negatively correlated with the number of functionally connected voxels in M1, S1FL and S1BF. Our results suggest that these techniques are useful tools to evaluate remarkable brain changes in the hyperacute stage of ischemic stroke.
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea.
Jihoon
J
Cha
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea.
Sung Tae
ST
Kim
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea; Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea.
Won Beom
WB
Jung
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea.
Yong Hee
YH
Han
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea.
Geun Ho
GH
Im
Department of Radiology Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea; Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon 16419, South Korea; Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul 06351, South Korea. Electronic address: hijunghee@skku.edu.
Jung Hee
JH
Lee
D000818:Animals; D016880:Anisotropy; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology*
Acute stroke; Brain imaging; Diffusion tensor imaging; Focal ischemia; Functional MRI; MRI