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experiments showing that large MRI signal changes were observable in the human brain following exposure to simple visual stimuli, using both blood oxygenation (BOLD) and flow contrast. The first dynamic video images of human brain activity appeared first at a meeting of the
Society for Magnetic Resonance in Medicine in August 1991 in San Francisco in a plenary session by colleague Tom Brady, and was subsequently published in 1992 in the Proceedings of the National Academy of Sciences. (in the same year that Ogawa and colleagues submitted their results subsequently published a year later in PNAS. That same issue also included the work of
223:, the recruitment of localized areas of neural tissue as different parts of the brain participate in tasks. The landmark results of Belliveau, et al., in 1991, using dynamic susceptibility contrast heralded the creation of a new field in functional activity mapping of the human brain using magnetic resonance imaging - fMRI.
178:(the distribution of blood and nutrients to tissue) and diffusion (the detection of random dispersion of particles, principally water) in living tissues. Together with MIT graduate student Daisy Chien, and colleagues Richard Buxton, Tom Brady and Bruce Rosen he was one of the earliest entrants in the field of
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had shown that oxygen depletion led to significant drops in MRI signal changes in large veins and the brain cortex itself, respectively, via a magnetic susceptibility mechanism analogous to that used by
Belliveau with exogenous tracers, but in this case using deoxygenated blood itself as the contrast
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database. This amounts to an average of more than 41 published manuscripts per day since the original method development 20 years earlier (24873 papers in 2011). To date no method has surpassed its combination of precision, safety and reliability in observing brain function. Kwong's discoveries were
262:
signal through the apparent change in T1 relaxation rates associated with the replenishment of blood in brain tissue, and demonstrated how the measured signal changes could be used to directly infer a quantitative measurement of the change in brain perfusion. This forms the basis of a second set of
226:
Two parallel developments in endogenous contrast set the stage of methods to map brain activity without injection of tracers or contrast agents. Contemporaneous work a decade earlier by
Thulborn, and Wright at Stanford, had shown that blood oxygenation levels could be measured by NMR methods. Later
191:
visualization the axonal fibers that connect neurons in the brain) . Chien and Kwong then used their early diffusion techniques to study human patients with stroke. In technically demanding circumstances (a low field MRI using conventional imaging, located in a parking lot trailer nearby the MGH)
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Kwong is an active researcher, authoring or co-authoring 97 papers from 1992 to 2011, in the period following the initial fMRI publication. His most current work addresses problems in quantitative brain perfusion measurement as well as studies of brain effects of the traditional
Chinese medical
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With this background, Kwong reasoned that the concepts of functional mapping by brain perfusion, and the assessment of oxygenation from purely endogenous signals could be combined into an entirely new method of studying human brain activity. In the spring of 1991 he performed his first human
212:(EPI) MRI instrument, capable of forming MRI images in 25 ms. The EPI method proved extremely powerful in the study of both perfusion and diffusion by allowing Kwong, and others, to evaluate dynamic changes in signal, such as the flow of blood labeled with injected magnetic
182:, which itself was opened by the pioneering experiments of Denis Le Bihan. In a conference paper in 1988 at the Society for Magnetic Resonance in Medicine the MGH group was the first to demonstrate diffusion anisotropy in the human brain, stating, "...
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we observed different diffusion patterns parallel and perpendicular to the midline of the brain, which was repeatable, and depended only on the direction of diffusion encoding gradient relative to the brain, regardless of which physical gradient was
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Consistent with his joint appointment in the
Massachusetts Eye and Ear Infirmary, he and his colleagues were able to demonstrate that MRI could be used to study diffusion and flow in the living eye. He and his colleagues pioneered the use of
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Moseley, ME; Cohen, Y; Mintorovitch, J; Chileuitt, L; Shimizu, H; Kucharczyk, J; Wendland, MF; Weinstein, PR (1990). "Early detection of regional cerebral ischemia in cats: comparison of diffusion- and T2-weighted MRI and spectroscopy".
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modern methods known now as arterial spin labeling, increasingly used when quantification of baseline and changing physiology is required. Kwong's was clearly the first work in this field to apply these methods to human brain mapping.
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Kwong's first publication in this area, and his first experiments, demonstrated the two principal methods of functional brain imaging from endogenous signals. The oxygenation level dependent signal, known now as
437:
Kwong, KK; Hopkins, AL; Belliveau, JW; Chesler, DA; Porkka, LM; McKinstry, RC; Finelli, DA; Hunter, GJ; Moore, JB; et al. (1991). "Proton NMR imaging of cerebral blood flow using (H2O)-O17".
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Belliveau JW, Kennedy DN, McKinstry RC, Buchbinder BR, Weisskoff RM, Cohen MS, Vevea JM, Brady TJ, Rosen BR (1991). "Functional mapping of the human visual cortex by magnetic resonance imaging".
720:
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The MGH-NMR Center group, led by John (Jack) Belliveau, recognized that dynamic perfusion methods could be adapted to demonstrate perfusion changes that occur as a result of brain "work",
725:
250:, then at Bell Labs, who had made similar findings. Most researchers credit Kwong and Ogawa independently with the discovery of what is now called Functional MRI (fMRI).
715:
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Thulborn, KR; Waterton, JC; Matthews, PM; Radda, GK (1982). "Oxygenation dependence of the transverse relaxation time of water protons in whole blood at high field".
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Functional MRI has proven extremely important in clinical and basic sciences. By
February 2012 more than 299,000 manuscripts were matched by the term, "fMRI," on the
240:) were pioneered in animal models by John Detre and Alan Koretsky. All of this was possible without the introduction of blood borne contrast agents.
710:
258:, has become the most popular because of its greater overall contrast/noise, but Kwong showed also that MRI could be used to detect a blood
705:
187:.". This anisotropy itself is the fundamental principle underlying the modern method of MRI tractography and structural connectomics (the
138:. He went on to receive his Ph.D. in physics from the University of California, Riverside studying photon-photon collision interactions.
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283:. He advanced to an assistant professorship in 1997, and since 2000 has been an associate professor at the Harvard Medical School.
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in Loma Linda, California, establishing his work in medical science. After one year he was invited to a research fellowship at the
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they were the first to demonstrate in human subjects the early drop in diffusivity seen in acute infarction in cats by
Moseley.
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630:"Intrinsic signal changes accompanying sensory stimulation: Functional brain mapping with magnetic resonance imaging"
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O as a water tracer in MRI and demonstrated that this novel approach could be used to measure brain blood flow.
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KK Kwong; JW Belliveau; DA Chesler; IE Goldberg; RM Weisskoff; BP Poncelet; DN Kennedy; BE Hoppel; MS Cohen;
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Upon joining the team at the MGH Nuclear
Magnetic Resonance (MGH-NMR) Center, Kwong pursued an interest in
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Chien, D; Buxton, RB; Kwong, KK; Brady, TJ; Rosen, BR (1990). "MR diffusion imaging of the human brain".
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agent. At the same time, methods to directly measure brain perfusion using spin inverted water (
566:"Dynamic Magnetic Resonance Imaging of Human Brain Activity During Primary Sensory Stimulation"
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Chien, D; Kwong, KK; Buonanno, F; Buxton, R; Gress, D; Brady, TJ; Rosen, BR (1992).
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In 1993, shortly after his fMRI discoveries, Kwong was made instructor in
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imaging. Following his work in PET, he began his involvement in
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In 1990, the MGH-NMR Center received the first clinical
628:; Tank; Menon; Ellermann; Kim; Merkle; Ugurbil (1992).
354:"MR diffusion imaging of cerebral infarction in humans"
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721:UC Berkeley College of Letters and Science alumni
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126:nuclear physicist. He is a pioneer in human
726:University of California, Riverside alumni
564:; H Cheng; TJ Brady; and BR Rosen (1992).
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130:. He received his bachelor's degree in
271:made while he was a research fellow.
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71:University of California, Riverside
160:PET (positron emission tomography)
136:University of California, Berkeley
67:University of California, Berkeley
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16:American brain imaging researcher
323:10.1097/00004728-199007000-00003
711:Harvard Medical School faculty
439:Magnetic Resonance in Medicine
396:Magnetic Resonance in Medicine
227:groundbreaking experiments by
156:Massachusetts General Hospital
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170:MRI, Diffusion, and Perfusion
539:10.1016/0304-4165(82)90333-6
706:American nuclear physicists
216:through the organ systems.
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164:magnetic resonance imaging
292:practice of acupuncture.
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657:10.1073/pnas.89.13.5951
593:10.1073/pnas.89.12.5675
504:10.1126/science.1948051
180:brain diffusion imaging
451:10.1002/mrm.1910220116
408:10.1002/mrm.1910140218
311:J Comput Assist Tomogr
238:arterial spin labeling
158:(MGH) in the field of
204:Functional MRI (fMRI)
146:In 1985, Kwong was a
120:Kenneth Kin Man Kwong
527:Biochim Biophys Acta
122:is a Hong Kong-born
648:1992PNAS...89.5951O
584:1992PNAS...89.5675K
496:1991Sci...254..716B
287:Continuing Research
210:echo planar imaging
108:Harvard University
98:Magnetic Resonance
490:(5032): 716–719.
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104:Institutions
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248:Seiji Ogawa
152:VA hospital
53:Citizenship
690:Categories
296:References
35:1948-03-28
281:radiology
176:perfusion
46:Hong Kong
562:R Turner
467:46361573
424:23754356
275:Academic
124:American
676:1631079
644:Bibcode
626:S Ogawa
612:1608978
580:Bibcode
547:6275909
512:1948051
492:Bibcode
483:Science
459:1798389
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189:in vivo
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229:Ogawa
672:PMID
635:PNAS
608:PMID
571:PNAS
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508:PMID
455:PMID
412:PMID
376:PMID
358:AJNR
327:PMID
260:flow
256:BOLD
221:e.g.
185:used
81:fMRI
29:Born
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