Electronic Posters: Neuroimaging - ismrm

14:30 4492. Characterization of Mild Hypoxic-Ischemic Injury in Multiple White Matter Tracts
in a Neonatal Rat Model by Diffusion Tensor MR Imaging
Silun Wang 1,2 , ED X. WU 3 , Ho-fai Lau 3 , Jing Gu 1 , Jinyuan Zhou 2 , Pek-lan Khong 1
1 Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong; 2 Radiology, Johns Hopkins
University School of Medicine, Baltimore, MD, United States; 3 Laboratory of Biomedical Imaging and Signal
Processing, The University of Hong Kong, Hong Kong, Hong Kong
We evaluated hypoxic-ischemic (HI)-induced white matter (WM) injury in a mild HI neonatal rat model from Day1 to 90 post-HI by
DTI. Results showed that significantly decreased FA in multiple injured WM tracts, including external capsule (EC), fornix (F),
cerebral peduncle (CP) and optical tracts (OT), at different time points, but no differences were demonstrated in anterior commissure
(AC). Our results support the use of DTI as an imaging biomarker to non-invasively monitor the severity and longitudinal changes of
mild HI-induced WM injury. Different severity and patterns of WM tract injury may reflect disturbances of cerebral blood supply in
this ischemic animal model.
15:00 4493. DTI of Adult Visual Pathways After Severe Neonatal Hypoxic-Ischemic Cerebral
Injury
Kevin C. Chan 1,2 , Abby Y. Ding 1,2 , Ed X. Wu 1,2
1 Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR,
China; 2 Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR,
China
This study employs in vivo diffusion tensor imaging (DTI) to determine the long-term outcomes of microstructural integrity along the
visual pathways after severe neonatal hypoxic-ischemic (HI) injury to the entire ipsilesional visual cortex in rats at postnatal day 7.
Quantitative analyses showed that, compared to age-matched normal brains, a significantly lower FA but higher λ//, λ┴ and diffusion
trace value were observed in the ipsilesional posterior optic tract in the HI-injured brains at postnatal day 60, whereas significantly
lower FA but mildly lower λ// and higher λ┴ and trace were observed in the ipsilesional prechiasmatic optic nerve and contralesional
anterior and posterior optic tracts. The results of this study are potentially important in determining and improving the functional
consequences of the brain lesion after most compensatory and reparative phases have been passed.
Wednesday 13:30-15:30 Computer 87
13:30 4494. Comparison of MRI Measured Mean Micro-Vessel Segment Length and Micro-
Vessel Radius and Laser Scan Confocal Microscopy After Embolic Stroke
Asamoah Bosomtwi 1,2 , Quan Jiang 2,3 , Li Zhang 2 , Zheng Gang Zhang 2,3 , Michael Chopp 2,3
1 Yerkes Imaging Center, Emory University, Atlanta, GA, United States; 2 Neurology, Henry Ford Hospital,
Detroit, MI, United States; 3 Physics, Oakland University, Rochester, MI, United States
We investigated vascular remodeling after stroke using MRI mean segment length (MSL) and vessel size index (VSI) measurement
and correlate the results with measurements using Laser Scanning Confocal Microscopy (LSCM). We demonstrate that MRI MSL and
VSI can detect the microvascular status of brain tissue with different ischemic damage. The MSL and VSI measured by MRI were
highly correlated with LSCM histological measurements. Our data demonstrate that these MRI measurements can quantitatively
evaluate microvascular remodeling after stroke.
14:00 4495. Cell-Based Treatment Induced White Matter Reorganization After Traumatic
Brain Injury Measured by Gaussian, Q-Space DTI, and Histology
Quan Jiang 1,2 , Guang Liang Ding, Siamak Pourabdollah-Nejad 1 , Chang Sheng Qu 3 ,
Asim Mahmood 3 , Li Zhang 1 , Zheng Gang Zhang 1 , Jiani Hu 4 , Nassan Bagher-Ebadian 1 ,
James R. Ewing 1 , Michael Chopp 1,2
1 Neurology, Henry Ford Health System, Detroit, MI, United States; 2 Physics, Oakland University, Rochester,
MI, United States; 3 Neurosurgery, Henry Ford Health System, Detroit, MI, United States; 4 MR Center, Wayne
State University, Detroit, MI, United States
We investigated cell-based treatment induced white matter remodeling after traumatic brain injury (TBI) using Gaussian, q-ball,
standard deviation (SD) DTI, and immuno-histochemistry staining. We demonstrate that in brain tissue with a preponderance of single
oriented fibers, Gaussian DTI can correctly identify white matter reorganization and detect changes of axonal orientation in the
boundary recovery region after TBI. However, SD and q-ball need to be employed to measure WM reorganization if substantial fiber
crossing is present in the recovery tissue. Our data suggest that combination SD and FA data may provide information about the stage
of white matter remodeling after TBI.