Traditional Posters: Diffusion & Perfusion - ismrm

1706. Early Diffusion Changes Following Controlled Cortical Impact Injury on a Rat
Model
Jiachen Zhuo 1,2 , Su Xu 1,2 , Jennifer Racz 3 , Da Shi 1,2 , Gary Fiskum 3 , Rao Gullapalli 1,2
1 Radiology, University of Maryland School of Medicine, Baltimore, MD, United States; 2 Core for Translational
Research in Imaging at Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD,
United States; 3 Anesthesiology and the Center for Shock Trauma and Anesthesiology Research, University of
Maryland School of Medicine, Baltimore, MD, United States
The understanding of tissue alterations at an early stage following traumatic brain injury (TBI) is critical for injury management and
prevention of more severe secondary damage. In this study, we investigated the early changes in tissue water diffusion at 2 hours and
4 hours following mild to moderate controlled cortical impact injury on a rat model. Our study indicates a distance effect from the site
of injury and suggests a therapeutic window of about 2-3 hours to limit the cascade of events that may lead to secondary injury.
1707. A Longitudinal Study of DTI in a Nonhuman Primate Model of Neuro-AIDS
Chun-xia Li 1 , Xiaodong Zhang 1 , Yingxia Li 1 , Amelia Komery 2 , Francis J. Novembre 3 ,
James G. Herndon 2
1 Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA,30329,
United States; 2 Divisions of Microbiology and Immunology, Yerkes National Primate Research Center, Emory
University, Atlanta, GA,30322; 3 Divisions of Neuroscience, Yerkes National Primate Research Center, Emory
University, Atlanta, GA,30322
DTI has been proposed as a quantitative marker of the neurological status of HIV+ patients. In this study, DTI imaging was used to
longitudinally detect white matter abnormalities in whole brain and specific regions of Simian immunodeficiency virus (SIV)-infected
monkeys, a reduction in FA and an increase in MD were observed evidently after viral inoculation and whole-brain FA changes
correlated significantly with CD4 depletion. Findings from this investigation support the use of DTI for measurement of HIV
associated neuropathologic changes. Further longitudinal study is needed to investigate the validation of DTI measures as a marker for
disease progression.
1708. Hyperammonemia and Edema: A DTI Study in the Adult Rat Brain
Nicolas Kunz 1,2 , Cristina Cudalbu 1 , Yohan Van de Looij 1,2 , Petra Hüppi 2 , Stephane
Sizonenko 2 , Rolf Gruetter 1,3
1 Laboratory of functional and metabolic imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne,
Lausanne, Switzerland; 2 Division of Child Growth &Development, University of Geneva, Geneva, Switzerland;
3 Department of Radiology, University of Geneva & Lausanne, Geneva & Lausanne, Switzerland
Ammonia is a neurotoxin that is implicated in the pathogenesis of hepatic encephalophaty, which is reported to be responsible for
brain edema. It is not yet clear whether brain edema is mostly vasogenic or cytotoxic. The aim of this study was to assess the effects of
hyperammonemia on the rat brain by using DTI at 9.4T. This study shows a rapid increase of the ventricle size during the three first
hours of infusion along with a decrease in ADC. As the ventricle size gets stabilized after 6h, the ADC keeps on decreasing, indicating
the formation of mild cytotoxic edema.
1709. Comparison of ADC Values Using Pulsed Field Gradient and Correlation Time
Diffusion Techniques in a Murine Model of Steatohepatitis at 11.7T
Stephan William Anderson 1 , Jorge A. Soto 1 , Holly N. Milch 1 , Hernan Jara 1
1 Radiology, Boston University Medical Center, Boston, MA, United States
The purpose of this study was to compare the ADC values obtained using pulsed field gradient (PFG) and correlation time diffusion
(CT-D) techniques in a mouse model of steatohepatitis at 11.7T. C57BL/6 mice fed a methionine-deficient choline-deficient (MCD)
diet to induce steatohepatitis were sacrificed intermittently throughout this period for ex vivo liver imaging. A comparison of the
parametric maps and whole sample histograms generated by the PFG and CTD techniques shows excellent agreement between the two
diffusion techniques. In all cases CT-D parametric maps had significantly higher SNR and the histogram width was narrower than
those generated using PFG technique.
Blood Flow in Animal Models
Hall B Tuesday 13:30-15:30
1710. Blood-Flow MRI of Non-Human Primate (Baboon) Retina
Hsiao-Ying Wey 1 , Jinqi Li 1 , Jiongjiong Wang 2 , Sung-Hong Park 1 , Timothy Q. Duong 1
1 Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States;
2 Radiology, University of Pennsylvania, Philadelphia, PA, United States
Quantitative blood flow measurement of the retina is critically important as many retinal diseases could perturb basal blood flow and
blood flow responses to stimulations. In this study, we developed and applied the pseudo-continuous ASL to improve ASL contrast,
and systematically explored blood-flow MRI of the retina in anesthetized baboon on a human clinical scanner. Anesthetized baboons
were used to exclude movement artifacts such that we could focus on evaluating hardware feasibility and imaging parameters for
high-resolution quantitative BF imaging of the retina as a first step toward evaluating potential human applications.