Traditional Posters: Diffusion & Perfusion - ismrm

University, Atlanta, GA,30322; 3 Divisions of Neuroscience, Yerkes National Primate Research Center, Emory
University, Atlanta, GA,30322
The regional cerebral blood flow (rCBF) measure has been proposed as a biomarker for HIV-associated CNS damage. In this study we
used the continuous arterial spin labeled (CASL) MRI technique to quantitatively measure the longitudinal pattern of rCBF change in
the selected ROIs of Simian Immunovirus Virus (SIV)-infected monkey model following infection. The finding indicates rCBF in
selected ROIs declined after the SIV inoculation resembling with the HIV+ patient, and the rCBF changes correlated well with the
depletion of CD4, which suggests CASL may be a surrogate biomarker for accessing the progression of the disease and treatment
development.
1758. Simultaneous CBF and BOLD Mapping of Electrical Acupoint Stimulation Induced
Brain Activity
Yue Zhang 1 , Christopher B. Glielmi, Yin Jiang 2 , Jing Liu 3 , Ying Hao 4 , Xiaoying Wang 3,4 ,
Jing Fang, 1,4 , Jisheng Han 2 , Jue Zhang, 1,4 , Xiaoping Hu 5
1 College of Engineering, Peking University, Beijing, China; 2 Neuroscience Research Institute, Peking
University, Beijing, China; 3 Dept.of Radiology, Peking University First Hospital, Beijing, China; 4 Academy for
Advanced Interdisciplinary Studies, Peking University, Beijing, China; 5 Dept. of Biomedical Engineering,
Georgia Institute of Technology / Emory University, Atlanta, United States
Blood oxygenation level dependent (BOLD) technique has been used to map brain activity related to electrical acupoint stimulation
(EAS) in previous pain-relief studies, but introduces relatively poor reproducibility and consistencies. In this study, the dual-echo
based simultaneous acquisition of cerebral blood flow (CBF) and BOLD was employed to provide the first evidence of CBF response
to EAS and inter-subjects¡¯ variation was compared between the two techniques. The results suggested that the sensitivity and
specificity to sensory and pain-related regions were consistent with previous findings. Moreover, CBF based inter-subjects¡¯variation
had a significant decrease than BOLD.
1759. Reproducibility of Arterial Spin Labeling and Blood-Oxygen Level Dependent
Measures of Cerebrovascular Reactivity Using a Controlled Cerebrovascular Challenge
Jeff D. Winter 1 , Jackie Leung 1 , Manohar Shroff 2,3 , Andrea Kassner 1,3
1 Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada;
2 Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada; 3 Medical Imaging, University
of Toronto, Toronto, Ontario, Canada
Cerebrovascular reactivity (CVR) measures of the cerebral blood flow (CBF) response to CO 2 may benefit clinical assessment of
cerebrovascular disease. CVR imaging is typically performed using indirect BOLD signal changes or arterial spin labeling (ASL) CBF
measures. In this study, we compared between-day reproducibility of BOLD and ASL (Look-Locker acquisition) CVR measures
performed with controlled CO 2 transitions in adults. Reproducibility was quantified with the between-day coefficient of variation
(CV). Reproducibility of ASL-CVR measures of CBF the response to CO 2 (CV < 17%) were similar to BOLD-CVR (CV < 19%),
which points to the potential clinical utility of this method.
1760. A Distributed Network of Cerebral Blood Flow Changes Accurately Discriminates
Methylphenidate and Atomoxetine: A Gaussian Process Pattern Recognition Approach
Andre Marquand 1 , Sara De Simoni, Owen O'Daly, Fernando Zelaya, Mitul Mehta
1 Centre for Neuroimaging Sciences, Institute of Psychiatry, London, United Kingdom
Methylphenidate and atomoxetine are widely used for the treatment of attention-deficit/hyperactivity disorder, but their differential
effects on human brain physiology are poorly understood. We apply a multivariate pattern recognition algorithm (Gaussian process
classification) to continuous arterial spin labelling data recorded while subjects were at rest which accurately discriminates
methylphenidate from atomoxetine and each drug from placebo. We show a distributed network of brain regions underlies
discrimination, with differential effects in putamen, anterior cingulate and temporal poles. Multivariate pattern recognition may be a
useful technique for detection of diffuse pharmacological effects.
1761. Does Pulsed Arterial Spin-Labeling Selectively Underestimate Responses to Global
Challenges?
Felipe B. Tancredi 1,2 , Claudine J. Gauthier, 2,3 , Cécile J. Madjar 2 , Richard D. Hoge 1,2
1 Biomedical Engineering, Université de Montréal, Montreal, Quebec, Canada; 2 UNF, CRIUGM, Montreal,
Quebec, Canada; 3 Physiology, Université de Montréal, Montreal, Quebec, Canada
ASL is a technique of particular interest for studies in which hypercapnia challenge is employed. We sought to test whether the
shortening in blood transit time that vasodilation by moderate hypercapnia may cause was leading to a systematic underestimation of
perfusion responses measured with ASL. We measured flow responses in three different moments: at hypercapnia, during visual
stimulus and when both were simultaneously present. We found that the response to the combined stimulus was a linear combination
of the responses the individual stimulus alone, that’s to say, the focal response to a visual stimulus during hypercapnia challenge was
not underestimated. ASL is a technique of particular interest for studies in which hypercapnia challenge is employed. We sought to
test whether the shortening in blood transit time that vasodilation by moderate hypercapnia may cause was leading to a systematic
underestimation of perfusion responses measured with ASL. We measured flow responses in three different moments: at hypercapnia,
during visual stimulus and when both were simultaneously present. We found that the response to the combined stimulus was a linear
combination of the responses the individual stimulus alone, that’s to say, the focal response to a visual stimulus during hypercapnia
challenge was not underestimated.