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London, United Kingdom 2013 Poster Session Red Cerebrovasc Dis 2013; 35 (suppl 3)1-854 415 243 Brain imaging How specific for the ischemic penumbra is 18F-fluoro-misonidazole (FMISO) PET? J.A. Alawneh1, R.R. Moustafa2, U. Jensen-Kondering3, S.T. Marrapu4, R.S. Morris5, F.I Aigbirhio6, T.D Fryer7, T.A. Carpenter8, E.A. Warburton9, J.C. Baron10 Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KING-DOM1, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KINGDOM2, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNIT-ED KINGDOM3, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KINGDOM4, Department of Clinical Neurosciences, University of Cambridge, Cam-bridge, UNITED KINGDOM5, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KINGDOM6, Department of Clinical Neurosciences, University of Cam-bridge, Cambridge, UNITED KINGDOM7, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KINGDOM8, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UNITED KINGDOM9, Department of Clinical Neurosciences, University of Cambridge and Inserm U894, Universite Paris Descartes, Cambridge/Paris, UNITED KINGDOM10 Background: Mapping the penumbra in acute stroke is of considerable clinical interest. Compared to gold-standard oxygen-15 PET, FMISO is a straightforward method. High FMISO uptake, which reflects tissue hypoxia, is assumed to be specific for the penumbra. However, recent animal data suggest it might also occur outside the latter. The aim of this clinical study was to examine i) the to-pography of abnormal FMISO uptake in relation to the oligemia and core; and ii) the local perfusion correlates of FMISO uptake. Methods: Patients with severe anterior circulation stroke and extensive penumbra on CT or MR per-fusion imaging underwent FMISO PET and repeat DWI and MRA as early as possible after iv t-PA, and f/u MRI at 1-4 weeks. High FMISO uptake was defined voxel-wise relative to a group of 10 age-matched controls, and mapped onto coregistered penumbra, oligemia and core maps as defined from perfusion, diffusion and f/u FLAIR. The relationship between local FMISO uptake and perfu-sion (TTP and CBF) was assessed using a template of circular ROIs. Results: Over 3 yrs 3 patients successfully completed this demanding protocol (age 54-81yrs; ad-mission NIHSS 16-22). All had persistent proximal MCA occlusion after t-PA and poor outcome. Perfusion imaging was performed 6-15hrs, and PET 12-26hrs after stroke onset. High FMISO up-take was present in all 3 patients (range 18-119mls) and mainly overlapped with the penumbra, but also with both core and oligemia in all cases, substantially so in 2 (range: 5-52 mls). Significant (p≤0.001) correlation between FMISO uptake and perfusion in the biologically expected direction was found in each case, with shallow FMISO increases followed by sharp bend around the penum-bra threshold. Conclusions: High FMISO uptake had the expected relationship with local perfusion and was pres-ent not just in the penumbra but also in the core and oligemia. This finding, if replicated in larger se-ries, would have implications for the clinical use of FMISO. 244 Brain imaging Tissue outcome in acute ischemic stroke: how useful is perfusion? G.W.J. Harston1, T. Okell2, M. Chappell3, N. Blockley4, Y.K. Tee5, J. Levman6, I. Reckless7, G. Pope8, F. Sheerin9, M. Cellerini10, N. Rane11, P. Jezzard12, S. Payne13, J. Kennedy14 University of Oxford, Oxford, UNITED KINGDOM1, University of Oxford, Oxford, UNITED KINGDOM2, University of Oxford, Oxford, UNITED KINGDOM3, University of Oxford, Oxford, UNITED KINGDOM4, University of Oxford, Oxford, UNITED KINGDOM5, University of Oxford, Oxford, UNITED KINGDOM6, Oxford University Hospitals NHS Trust, Oxford, UNITED KING-DOM7, Oxford University Hospitals NHS Trust, Oxford, UNITED KINGDOM8, Oxford University Hospitals NHS Trust, Oxford, UNITED KINGDOM9, Oxford University Hospitals NHS Trust, Oxford, UNITED KINGDOM10, Oxford University Hos-pitals NHS Trust, Oxford, UNITED KINGDOM11, University of Oxford, Oxford, UNITED KING-DOM12, University of Oxford, Oxford, UNITED KINGDOM13, University of Oxford, Oxford, UNITED KINGDOM14 Introduction Salvaging the ischemic penumbra has been the goal of acute stroke therapy for the past 30 years. In-creasingly it is pragmatically defined by a mismatch between the presenting perfusion deficit and the infarct, defined by diffusion-weighted imaging (DWI). Preliminary data identifying the relationship between serial perfusion and tissue fate are presented here. Methods Patients with ischemic stroke are recruited within 6hrs of symptom onset and undergo serial MRI: on presentation, at 1 day, 1 week and 1 month. MRI protocols include DWI, fluid attenuated inver-sion recovery (FLAIR), and quantitative arterial spin labeling (ASL). Regions of interest (ROI) were defined using DWI and perfusion on presentation and co-registered FLAIR at 1 month. Core infarct was defined as DWI positive, FLAIR positive (DWI+FLAIR+) and the mismatch between core and final infarct as DWI negative, FLAIR positive (DWI-FLAIR+). Hypoperfused tissue that did not in-farct by 1month was also defined (Perf+FLAIR-). Results A significant perfusion deficit was identified in all patients and in all ROI, using absolute estimates and relative to contralateral. The degree of hypoperfusion did not vary significantly between DWI+- FLAIR+, DWI-FLAIR+ or Perf+FLAIR- tissue at presentation. Subsequent reperfusion did not help to predict tissue outcome. Hyperemic reperfusion was also observed and was associated with symp-tomatic intracranial hemorrhage without thrombolysis in 1 patient. Conclusions These early data suggest that DWI+FLAIR+, DWI-FLAIR+ and Perf+FLAIR- tissue are not distinct in terms of perfusion deficit on presentation or reperfusion pattern over time. This may explain the observed difficulty of using perfusion thresholds to define ischemic penumbra. Perfusion data are re-quired but not sufficient to determine fate and the addition of methods to measure metabolic activity of tissue at presentation may provide a better insight into potential tissue outcomes.


Karger_ESC London_2013
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