Research Topics
| H AySummaryAffiliation: Massachusetts General Hospital Country: USA Publications
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Detail Information
Publications
Transient ischemic attack with infarction: a unique syndrome?Hakan Ay
Department of A A Martinos Center for Biomedical Imaging and Stroke Service, Department of Radiology, Boston, MA 02129, USA
Ann Neurol 57:679-86. 2005..3% in those with ischemic stroke. TIA with infarction appears to have unique features separate from TIA without infarction and ischemic stroke. We propose identifying TSI as a separate clinical syndrome with distinct prognostic features...- Clinical- and imaging-based prediction of stroke risk after transient ischemic attack: the CIP modelHakan Ay
AA Martinos Center for Biomedical Imaging and Stroke Service, Departments of Neurology and Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown MA 02129, USA
Stroke 40:181-6. 2009..We sought to combine imaging and clinical features to improve predictions for 7-day stroke risk after transient ischemic attack... - An evidence-based causative classification system for acute ischemic strokeHakan Ay
A A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Ann Neurol 58:688-97. 2005..The SSS-TOAST is a dynamic algorithm that can accommodate modifications as new epidemiological data accumulate and diagnostic techniques advance... - Severity of leukoaraiosis and susceptibility to infarct growth in acute strokeHakan Ay
A A Martinos Center for Biomedical Imaging and Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown, MA 02129, USA
Stroke 39:1409-13. 2008..We hypothesized that the volume of LA correlated with the proportion of initially ischemic but eventually infarcted tissue in acute human stroke... - Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke researchHakan Ay
Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown MA 02129, USA
Stroke 39:1171-6. 2008..We sought to quantify the variance imposed by measurement error in DWI and PWI lesion volume measurements in ischemic stroke... - A computerized algorithm for etiologic classification of ischemic stroke: the Causative Classification of Stroke SystemHakan Ay
AA Martinos Center for Biomedical Imaging and Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown, MA 02129, USA
Stroke 38:2979-84. 2007..In this article, we present an automated version of the SSS-TOAST, the Causative Classification System (CCS), to facilitate its utility in multicenter settings... - A score to predict early risk of recurrence after ischemic strokeH Ay
Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Neurology 74:128-35. 2010..There is currently no instrument to stratify patients presenting with ischemic stroke according to early risk of recurrent stroke. We sought to develop a comprehensive prognostic score to predict 90-day risk of recurrent stroke... - Neuroanatomic correlates of stroke-related myocardial injuryH Ay
A A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Neurology 66:1325-9. 2006..Myocardial injury can occur after ischemic stroke in the absence of primary cardiac causes. The neuroanatomic basis of stroke-related myocardial injury is not well understood... - Advances in the diagnosis of etiologic subtypes of ischemic strokeHakan Ay
Stroke Service and A A Martinos Center for Biomedical Imaging, Departments of Neurology and Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown, MA, 02129, USA
Curr Neurol Neurosci Rep 10:14-20. 2010..This article highlights important theoretical aspects of etiologic stroke classification and reviews major etiologic classification systems that have benefited from recent advances in etiologic stroke evaluation... - Middle cerebral artery infarcts encompassing the insula are more prone to growthHakan Ay
Department of Neurology, A A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
Stroke 39:373-8. 2008.... - Severity of leukoaraiosis determines clinical phenotype after brain infarctionE M Arsava
A A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown, MA 02129, USA
Neurology 77:55-61. 2011.... - Severity of leukoaraiosis correlates with clinical outcome after ischemic strokeE M Arsava
AA Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Neurology 72:1403-10. 2009..Leukoaraiosis (LA) is closely associated with aging, a major determinant of clinical outcome after ischemic stroke. In this study we sought to identify whether LA, independent of advancing age, affects outcome after acute ischemic stroke... - Diffusion-weighted magnetic resonance imaging identifies the "clinically relevant" small-penetrator infarctsJ Oliveira-Filho
Department of Neurology Stroke Service, Blake 1291B, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114, USA
Arch Neurol 57:1009-14. 2000..Diffusion-weighted imaging (DWI) can identify the clinically relevant "index infarction" in such circumstances, since it differentiates between acute and chronic lesions... - Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathyF O Lima
Department of Neurology, Stroke Service, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
AJNR Am J Neuroradiol 31:817-21. 2010.... - Conversion of ischemic brain tissue into infarction increases with ageHakan Ay
The AA Martinos Center, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
Stroke 36:2632-6. 2005..We hypothesize that age is a marker for tissue susceptibility to ischemia and thus plays a role in determining tissue outcome in human stroke... - The Causative Classification of Stroke system: an international reliability and optimization studyE M Arsava
A A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
Neurology 75:1277-84. 2010..We determined whether CCS demonstrates high interrater reliability in order to be useful for international multicenter studies... - Collateral vessels on CT angiography predict outcome in acute ischemic strokeMatthew B Maas
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, USA
Stroke 40:3001-5. 2009.... - National Institutes of Health Stroke Scale score is poorly predictive of proximal occlusion in acute cerebral ischemiaMatthew B Maas
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, USA
Stroke 40:2988-93. 2009..Use of National Institutes of Health Stroke Scale (NIHSS) score to predict a proximal arterial occlusion (PO) is suggested by several case series as a viable method of selecting cases appropriate for multimodal imaging... - Vagus nerve stimulation reduces infarct size in rat focal cerebral ischemiaIlknur Ay
MGH MIT HMS A A Martinos Center for Biomedical Imaging, Massachusetts General Hospital East, 149 13th Street, Charlestown, MA O2129, USA
Neurosci Lett 459:147-51. 2009..The functional score improved by 50% in experimental group 1 and 44% in experimental group 2 (p<0.05 for both groups). Conclusion: VNS appears to offer protection against acute ischemic brain injury... - CT and conventional and diffusion-weighted MR imaging in acute stroke: study in 691 patients at presentation to the emergency departmentMark E Mullins
Neuroradiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, GRB285, Boston, MA 02114, USA
Radiology 224:353-60. 2002..After 12 hours, accuracy was equivalent. CONCLUSION: In the diagnosis of stroke in the early period (<12 hours after presentation), DW MR imaging is superior to conventional MR imaging and CT... - Wake-up stroke: clinical and neuroimaging characteristicsGisele S Silva
Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA giselesampaio hotmail com
Cerebrovasc Dis 29:336-42. 2010..In these patients, in whom the time from symptom onset is uncertain, brain imaging is a potential strategy to characterize the ischemia duration and the presence of salvageable brain tissue... - 'Footprints' of transient ischemic attacks: a diffusion-weighted MRI studyHakan Ay
Stroke Service of the Neurology, Massachusetts General Hospital, and Harvard Medical School, Boston, Mass, USA
Cerebrovasc Dis 14:177-86. 2002..We aimed to determine the proportion and clinical characteristics of patients with TIA who harbor infarction(s) on DWI... - Admission international normalized ratio and acute infarct volume in ischemic strokeHakan Ay
Department of Neurology, Stroke Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA
Ann Neurol 64:499-506. 2008..We explored the relation between admission international normalized ratio (INR) and acute infarct volume in patients with ischemic stroke... - Localization of clinical syndromes using DWI: two examples of the "capsular" warning syndromeJ Oliveira-Filho
Department of Neurology-Stroke Service, Blake 1291B, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
J Neuroimaging 11:44-7. 2001..DWI's ability to differentiate between acute and chronic infarcts may assist in more accurate localization of clinical syndromes... - The real estate factor: quantifying the impact of infarct location on stroke severityNina M Menezes
Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and the Harvard Massachusetts Institute of Technology Division of Health Sciences and Technology, Boston, MA, USA
Stroke 38:194-7. 2007..In the current study, we sought to quantify the impact of location on neurological deficit severity and to delineate this impact from that of volume... - Mild induced hypertension improves blood flow and oxygen metabolism in transient focal cerebral ischemiaHwa Kyoung Shin
Stroke and Neurovascular Regulation Laboratory, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
Stroke 39:1548-55. 2008..We, therefore, tested whether pharmacologically induced hypertension improves cerebral blood flow and metabolism and tissue outcome in acute stroke using optical imaging with high spatiotemporal resolution... - Automated perfusion-weighted MRI using localized arterial input functionsCory Lorenz
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Division of Health Sciences and Technology, Harvard/MIT, Charlestown, Massachusetts 08129, USA
J Magn Reson Imaging 24:1133-9. 2006..Similarly, the local MTT lesion volumes had the least mean squared error (MSE). CONCLUSION: Automated CBF calculation using local AIFs is feasible and appears to produce more useful CBF maps... - Effect of using local arterial input functions on cerebral blood flow estimationCory Lorenz
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA
J Magn Reson Imaging 24:57-65. 2006..CONCLUSION: The local-AIF technique results in an increase in the calculated CBF values for tissues with D/D, consistent with a reduction in the errors associated with D/D... - Prediction of early stroke risk in transient symptoms with infarction: relevance to the new tissue-based definitionE Murat Arsava
A A Martinos Center for Biomedical Imaging, Department of Radiology Massachusetts General Hospital, Harvard Medical School, Charlestown MA 02129, USA
Stroke 42:2186-90. 2011..We sought to assess the utility of a Web-based recurrence risk estimator (RRE; http://www.nmr.mgh.harvard.edu/RRE/) originally developed for use in patients with ischemic stroke for predicting 7-day risk of stroke in patients with TSI... - Age-dependent susceptibility to infarct growth in womenFigen Gokcay
AA Martinos Center for Biomedical Imaging and Stroke Service, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Room 2301, Charlestown, MA 02129, USA
Stroke 42:947-51. 2011..We sought to identify whether the proportion of initially ischemic to eventually infarcted tissue was different between men and women with ischemic stroke... - Creatine kinase-MB elevation after stroke is not cardiac in origin: comparison with troponin T levelsHakan Ay
Department of Neurology, Hacettepe University Hospital, Ankara, Turkey
Stroke 33:286-9. 2002..Troponin T has superior sensitivity and specificity to CK-MB in revealing minor myocardial injury. Therefore, we studied troponin T levels after stroke to determine whether troponin T increases in parallel to CK-MB... - How much should one rely on computed tomography in patients with TIA in the era of diffusion-weighted magnetic resonance imaging?Hakan Ay
Stroke 35:e72; author reply e72. 2004 - Diffusion-weighted MRI for the "small stuff": the details of acute cerebral ischaemiaAchim Gass
NMR Research Neurology, Department of Neurology, Universitaetsklinikum Mannheim, Germany
Lancet Neurol 3:39-45. 2004..DWI is becoming an important technique for optimum management of patients... - Hyperhomocysteinemia is associated with the presence of left atrial thrombus in stroke patients with nonvalvular atrial fibrillationHakan Ay
Department of Neurology, Hacettepe University Hospital, Ankara, Turkey
Stroke 34:909-12. 2003..In the present study, we hypothesized that high homocysteine might be associated with thrombus formation in another stasis-related condition, atrial fibrillation... - Physiological noise in MR images: an indicator of the tissue response to ischemia?Harris H Wang
Medical Engineering Medical Physics Program, Division of Health Sciences and Technology, Harvard University Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
J Magn Reson Imaging 27:866-71. 2008..To determine whether measuring signal intensity (SI) fluctuations in MRI time series data from acute stroke patients would identify ischemic tissue... - Statin potentiates human platelet eNOS activity without enhancing eNOS mRNA and protein levelsMuge Yemisci
Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
Cerebrovasc Dis 26:190-8. 2008..Hence, we investigated changes in eNOS activity, mRNA and protein levels after statin treatment in human platelets, which are readily accessible unlike arteries... - Persistence of hyperbaric oxygen-induced oxidative effects after exposure in rat brain cortex tissueHakan Ay
Department of Undersea and Hyperbaric Medicine, Gulhane Military Medical Academy, 06018 Etlik Ankara, Turkey
Life Sci 80:2025-9. 2007..In conclusion, the oxidative effect of HBO was shown to persist only for 1 h. Further studies should be performed to elucidate the possible molecular interactions during this period... - Protective effects of exogenously administered or endogenously produced melatonin on hyperbaric oxygen-induced oxidative stress in the rat brainKadir Dundar
Department of Undersea and Hyperbaric Medicine, Gulhane Military Medical Academy, Ankara, Turkey
Clin Exp Pharmacol Physiol 32:926-30. 2005..5. In conclusion, HBO caused oxidative stress and melatonin exhibited protective effects. Both endogenously produced and exogenously administered melatonin were found to be effective... - Primary angiitis of the central nervous system and silent cortical hemorrhagesHakan Ay
Department of Neurology, Hacettepe University Hospitals, Sihhiye 06100, Ankara, Turkey
AJNR Am J Neuroradiol 23:1561-3. 2002..The identification of petechial hemorrhages by gradient-echo MR imaging promises to be a valuable surrogate marker supporting the diagnosis of primary angiitis of the CNS... - Unusually prolonged progressing stroke: an expanding anterior cerebral artery infarctionHakan Ay
Department of Neurology, Hacettepe University Hospital, Ankara, Turkey
Cerebrovasc Dis 13:64-6. 2002..Occasional patients like ours indicate that stroke is a dynamic disorder with an extremely variable clinical course and state of tissue injury... - Effect of hyperbaric oxygen on flow-mediated vasodilation: an ultrasound studyMutlu Saglam
Department of Radiology, Gulhane School of Medicine, Ankara, Turkey
J Ultrasound Med 27:209-14. 2008..The purpose of this study was to investigate the effect of hyperbaric oxygen (HBO) treatment on flow-mediated vasodilation (FMD) by ultrasound examination... - Echocardiographic predictors of left atrial appendage spontaneous echocontrast in patients with stroke and atrial fibrillationNecla Ozer
Department of Cardiology, Hacettepe University, Ankara, Turkey
J Am Soc Echocardiogr 18:1362-5. 2005..The purpose of this study was to define the new transesophageal echocardiographic predictors of SEC for patients with stroke and atrial fibrillation...
Research Grants
- Heart-Brain Interactions In Human Acute Ischemic StrokeHakan Ay; Fiscal Year: 2010....