TRADITIONAL POSTER - ismrm

Poster Sessions
significantly correlated with enhanced functional connectivity within this region. Our data suggest that improved neuroanatomical connectivity underlies
enhancement of functional connectivity in reorganizing neuronal networks after stroke.
2231. Evolution of Functional Connectivity After Transient Stroke in Rats
Woo Shim 1,2 , Kwangyeol Yeol Baek 1,2 , Jeong Kon Kim 3 , Guangping Dai 1 , Jaeseong Jeong 2 , Bruce Rosen 1 ,
Young Ro Kim 1
1 Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 2 Bio and brain engineering,
KAIST, Yuseong-gu, Daejeon, Korea, Republic of; 3 Radiology, Asan Medical Center, Seoul, Korea, Republic of
We monitored changes of resting-states functional connectivity using cross-correlation technique over a period of 30 days after transient cerebral ischemic
damage. Averaged correlation strengths among some ROIs in stroke rats monotonically increased within the contralesional hemisphere over time, eventually
matching those in control group. Despite the slight recovery, cross-correlation values measured within ipsilesional hemisphere and between bilateral
hemispheres show severely impaired functional connectivity over 30 days after stroke. Although highly speculative, the data demonstrated that the initial
limb dysfunction is related to the loss of brain connectivity in both ipsi- and contra-lesonal brain regions and that the restoration of function may be
associated more with the increase of functional connectivity within the contralesional than the ipsilesional hemisphere.
2232. Multi-Parametric Stroke Imaging Protocol for Mice Using a 1H Cryo Probe at 9.4 T
Patrick Michael Heiler 1 , Friederike Lara Vollmar 2 , Melanie Heilmann 1 , Andreas Lemke 1 , Stephen Meairs 2 ,
Marc Fatar 2 , Lothar Rudi Schad 1
1 Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany; 2 Experimental Neurology, Heidelberg
University, Mannheim, Germany
The investigation of rt-PA therapy after MCAo in mice by means of MRI requires adequate resolution for the brain size of about 1 x 1 cm², in measurement
times acceptable for follow-up studies. We present a protocol including t2-weighted imaging, diffusion weighted imaging and a TOF angiography using a
1H surface cryo coil at 9.4T. The results demonstrate that rt-PA therapy leads to reperfusion of the MCA and significantly reduces the extension of ischemia.
The short measurement time makes the protocol suitable for both, detection of the MCAo success immediately after the surgery and temporal evolution
studies after rt-PA therapy.
2233. High-Resolution 31P Chemical Shift Imaging of Acute Stroke at 11.7T
Andrew Bresnen 1 , Fang Du 1 , Qiang Shen 1 , Geoffrey Clarke 2 , Timothy Q. Duong 1
1 Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Tx, United States; 2 Radiological
Sciences, University of Texas Health Science Center at San Antonio, San Antonio, Tx, United States
In vivo 31P chemical shift imaging allows direct measurements of the high energy phosphates. 31P NMR has proven useful for investigating the
bioenergetics in normal brain. However, the low SNR, long scan time and low spatial resolution of 31P NMR have prevented its widespread use, particularly
in the study of acute stroke. This study implemented and optimized 31P CSI on rat brain with high spatio-temporal resolution at 11.7T. This approach, along
with 1H diffusion, perfusion and T2 MRI, was used to investigate changes of high energy phosphates in stroke rats at 1, 3 and 24 hrs after onset.
2234. Diffusion Tensor Echo Planar Imaging of Mouse Brain After Brief Focal Middle Cerebral Artery
Occlusion at 14T
Hongxia Lei 1,2 , Yohan Van de Looij 1,3 , Nicolas Kunz 1,3 , Carole Berthet 4 , Lorenz Hirt 4 , Rolf Gruetter 1,5
1 LIFMET, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2 Radiology, University of Lausanne, Lausanne,
Switzerland; 3 Pediatrics, University of Geneva, Geneva, Switzerland; 4 Neurology, Centre Hospitalier Universitaire Vaudois,
Lausanne, Switzerland; 5 Radiology, University of Geneva, Geneva, Switzerland
Diffusion tensor imaging allowed accurately measuring ADC, which is very essential for stroke studies. We sought to establish feasibilities of EPI-version
DTI of mouse brain after brief ischemia at 14T. The nearly artifact free DTI images allowed accurately measuring ADC maps and help localizing ischemic
core more precisely when no abnormal T 2 contrast expressed.
2235. Cerebral Blood Flow Autoregulation in Transient Ischemic Tissue Expressed Delayed Hyperperfusion
Two Days After Middle Cerebral Arterial Occlusion
Kazuhiro Nakamura 1 , Yasushi Kondoh 1 , Shigenori Mizusawa 1 , Junko Yoshida 1 , Hajime Miyata 1 , Toshibumi
Kinoshita 1
1 Akita Research Institute for Brain and Blood Vessels, Akita, Japan
Strong hyperperfusion was observed in transient ischemic tissue 48-72 h after middle cerebral artery occlusion (MCAO). To investigate a physiological
reason for the phenomena, we have performed experiments for revealing cerebral blood flow (CBF) autoregulation in transient ischemic tissue using a lower
body negative pressure method. Using the lower body negative pressure method, we can avoid an estimation error in CASL from a blood oxygen dependent
signal change. The results show CBF in ischemic tissue is higher than normal in all blood pressure range and it should indicate the autoregulatory failure of
small pial artery in the ischemic tissue.
2236. Incorporating ADC Temporal Profiles in Acute Stroke to Predict Ischemic Tissue Fate
Virendra R. Desai 1 , Qiang Shen 1 , Timothy Q. Duong 1
1 Research Imaging Institute, Ophthalmology/Radiology, UT Health Science San Antonio, San Antonio, TX, United States
Acute diffusion data has been used to predict ischemic tissue fate on a pixel-by-pixel basis. Previous predictions however were made based on acute MRI
data from a single time point. This study proposes a novel approach to incorporate the temporal characteristics of acute ADC (apparent diffusion coefficient)
changes to characterize tissue fate based on a pixel-by-pixel basis. This approach was tested on rat stroke models subjected to permanent and 60-min middle
cerebral artery occlusion (MCAO). We concluded that there were distinct temporal patterns that determined tissue salvageability.