TRADITIONAL POSTER - ismrm

Poster Sessions
2237. tPA-Induced Suppression of Cerebrovascular Parameters in Acute Rat Stroke Model: Dynamic MRI
Study
Young Ro Kim 1 , Xiang Fan 2 , Guangping Dai 1 , Jeong Kon Kim 3 , Bruce R. Rosen 1 , xiaoying Wang 2
1 Radiology, Martinos Center for Biomedical Imaging / Massachusetts General Hospital, Charlestown, MA, United States; 2 Radiology,
Neuroprotection Research laboratory / Massachusetts General Hospital, Charlestown, MA, United States; 3 Radiology, Asan Medical
Center, Seoul, Korea, Republic of
Tissue plasminogen activator (tPA) has been frequently used for treating acute ischemic stroke based on re-canalization, reopening of occluded vessels for
the reinstitution of regional blood perfusion. Despite the promising clinical outcomes, exogenous tPA may worsen the ischemia-induced blood brain-barrier
disruption, elevate risks of intracranial hemorrhage, and in part consequently reduces the therapeutic time window. Therefore, it is critically important to
understand the overall effects of tPA treatment on cerebrohemodynamics. In this study, we investigated the vasoreactivity in response to intravenously
administered tPA and to systemic hypercapnia before and after tPA using a permanent focal stroke rat model.
2238. Validation of T2* Weight Signal Change of Oxygen Challenge as a Potential Better Penumbra
Estimation
Fang Du 1 , Shiliang Huang 1 , Qiang Shen 1 , Timothy Q. Duong 1
1 Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
Mismatch of diffusion/perfusion by MRI has been used as an estimate of the ischemic penumbra, but there are large parts of the mismatch region appear not
to at risk and it was also reported that some of the apparent diffusion coefficient reduction area can be salvaged by early reperfusion. It was proposed that
T2* weight signal change of oxygen challenge could be a better penumbra estimation. This study applied OC technique to a group of transient ischemia rats
and proved this hypothesis.
2239. MRI of Emboli Localization and Lysis in an Embolic Model of Rat Middle Cerebral Artery Occlusion
Ronn Philip Walvick 1 , Bernt Torre Bratane 2 , James Bouley 2 , Nills Henninger 2 , Mitchell Albert 1 , Marc
Fisher 1
1 Radiology, University of Massachusetts Medical School, Worcester, MA, United States; 2 Neurology, University of Massachusetts
Medical School, Worcester, MA, United States
We present a novel technique to localize and observe the dynamics of clot lysis during tissue Plasminogen Activator (tPA). Prior to fabrication of clots,
blood was doped with Magnevist (Bayer, Wayne, NJ). Clots were withdrawn tubing and injected into the left common carotid artery at the base of the skull
causing a middle cerebral artery occlusion. MRI consisted of diffusion, perfusion, and T1 weighted imaging for clot localization, and MR angiography.
During tPA administration, serial T1 weighted and perfusion imaging was performed. Our results demonstrate the ability of this method to detect clots in a
preclinical model of embolic stroke.
2240. Magnetic Resonance Imaging as an In-Vivo Tool for Evaluating Efficacy of Brain Edema Prevention
Therapy in a Rat Stroke Model
Denise C. Welsh 1 , Andrew Danziger 2 , Theodore Detwiler 2 , Hillary Regan 2 , Joseph J. Lynch 2 , Christopher
P. Regan 2 , Donald S. Williams 1 , Alexandre Coimbra 1
1 Imaging, Merck, West Point, Pa, United States; 2 Central Pharmacology, Merck, West Point, Pa, United States
While numerous studies have used MRI techniques for studying stroke pathology, there has been limited use of MR parameters as in vivo markers of novel
treatment efficacy. Here, Gd-enhanced T1-w and T2-w MR data were used to verify the efficacy of pre- and post-infarct treatment with a novel KDR kinase
inhibitor (KDRi) known to reduce vascular permeability and therefore, BBB leakage. In line with previously published ex-vivo data (1), in-vivo MRI results
suggest efficacy of KDRi treatment in reducing BBB leakage and edema formation, as indicated by tissue water content.
2241. Longitudinal Assessment of Brain Damage in Hypertension Rats Using Diffusion Tensor Imaging
Chien-Yuan Lin 1 , Cheng-Di Chiu 2,3 , Ming-Huang Lin 1 , Wai-Mui Cheung 1 , Teng-Nan Lin 1 , Chen Chang 1
1 Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; 2 Graduate Institute of Medical Sciences, National Defense
Medical Center, Taipei, Taiwan; 3 Department of Neurosurgery, Chang-Hua Hospital, Chang-Hua, Taiwan
The elevated blood pressure is considered to be the main risk factor of stroke and is highly associated with white matter lesions. This study aimed to
investigate the change of white matter microstructure under various levels of blood pressures.
2242. MRI Monitoring of Endogenous Stem Cell Therapies in Animal Models of Stroke
Voytek Gretka 1 , Lisa Di Diodato 1 , Amy Hoyles 2 , Nancy J. Lobaugh 3 , Cindi Morshead 2 , Greg J. Stanisz 1
1 Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; 2 Department of Surgery, University of Toronto,
Toronto, ON, Canada; 3 Cognitive Neurology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
In animal models of stroke, endogenous neural precursor cells can be activated with growth factors such as epidermal growth factor (EGF) and
erythropoietin (EPO) leading to increased neurogenesis and behavioural recovery. We demonstrated the feasibility of using MR to distinguish between
regenerating and pathological tissues when using endogenous stem cell therapies in rats. Tissue growth in the lesion site has MR characteristics (T 1 and T 2 )
similar to that of normal brain tissue, and differs distinctly from the cavity present when animals are untreated. MRI is able to predict the outcome of the
treatment as early as 2 weeks post stroke.