H Ay

Summary

Affiliation: Massachusetts General Hospital
Country: USA

Publications

  1. ncbi request reprint 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
  2. doi request reprint Clinical- and imaging-based prediction of stroke risk after transient ischemic attack: the CIP model
    Hakan 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
  3. ncbi request reprint An evidence-based causative classification system for acute ischemic stroke
    Hakan 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
  4. doi request reprint Severity of leukoaraiosis and susceptibility to infarct growth in acute stroke
    Hakan 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
  5. doi request reprint Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research
    Hakan 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
  6. ncbi request reprint A computerized algorithm for etiologic classification of ischemic stroke: the Causative Classification of Stroke System
    Hakan 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
  7. pmc A score to predict early risk of recurrence after ischemic stroke
    H Ay
    Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
    Neurology 74:128-35. 2010
  8. ncbi request reprint Neuroanatomic correlates of stroke-related myocardial injury
    H 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
  9. pmc Advances in the diagnosis of etiologic subtypes of ischemic stroke
    Hakan 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
  10. doi request reprint Middle cerebral artery infarcts encompassing the insula are more prone to growth
    Hakan 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

Research Grants

Collaborators

Detail Information

Publications43

  1. ncbi request reprint 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...
  2. doi request reprint Clinical- and imaging-based prediction of stroke risk after transient ischemic attack: the CIP model
    Hakan 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...
  3. ncbi request reprint An evidence-based causative classification system for acute ischemic stroke
    Hakan 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...
  4. doi request reprint Severity of leukoaraiosis and susceptibility to infarct growth in acute stroke
    Hakan 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...
  5. doi request reprint Interexaminer difference in infarct volume measurements on MRI: a source of variance in stroke research
    Hakan 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...
  6. ncbi request reprint A computerized algorithm for etiologic classification of ischemic stroke: the Causative Classification of Stroke System
    Hakan 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...
  7. pmc A score to predict early risk of recurrence after ischemic stroke
    H 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...
  8. ncbi request reprint Neuroanatomic correlates of stroke-related myocardial injury
    H 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...
  9. pmc Advances in the diagnosis of etiologic subtypes of ischemic stroke
    Hakan 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...
  10. doi request reprint Middle cerebral artery infarcts encompassing the insula are more prone to growth
    Hakan 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
    ....
  11. pmc Severity of leukoaraiosis determines clinical phenotype after brain infarction
    E 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
    ....
  12. pmc Severity of leukoaraiosis correlates with clinical outcome after ischemic stroke
    E 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...
  13. ncbi request reprint Diffusion-weighted magnetic resonance imaging identifies the "clinically relevant" small-penetrator infarcts
    J 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...
  14. pmc Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathy
    F O Lima
    Department of Neurology, Stroke Service, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
    AJNR Am J Neuroradiol 31:817-21. 2010
    ....
  15. ncbi request reprint Conversion of ischemic brain tissue into infarction increases with age
    Hakan 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...
  16. pmc The Causative Classification of Stroke system: an international reliability and optimization study
    E 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...
  17. pmc Collateral vessels on CT angiography predict outcome in acute ischemic stroke
    Matthew B Maas
    Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, USA
    Stroke 40:3001-5. 2009
    ....
  18. pmc National Institutes of Health Stroke Scale score is poorly predictive of proximal occlusion in acute cerebral ischemia
    Matthew 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...
  19. doi request reprint Vagus nerve stimulation reduces infarct size in rat focal cerebral ischemia
    Ilknur 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...
  20. ncbi request reprint CT and conventional and diffusion-weighted MR imaging in acute stroke: study in 691 patients at presentation to the emergency department
    Mark E Mullins
    Neuroradiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, GRB285, Boston, MA 02114, USA
    Radiology 224:353-60. 2002
    ..To compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance (MR) imaging in a consecutive series of patients at presentation to the emergency department with symptoms of acute stroke...
  21. pmc Wake-up stroke: clinical and neuroimaging characteristics
    Gisele 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...
  22. ncbi request reprint 'Footprints' of transient ischemic attacks: a diffusion-weighted MRI study
    Hakan 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...
  23. doi request reprint Admission international normalized ratio and acute infarct volume in ischemic stroke
    Hakan 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...
  24. ncbi request reprint Localization of clinical syndromes using DWI: two examples of the "capsular" warning syndrome
    J 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...
  25. ncbi request reprint The real estate factor: quantifying the impact of infarct location on stroke severity
    Nina 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...
  26. pmc Mild induced hypertension improves blood flow and oxygen metabolism in transient focal cerebral ischemia
    Hwa 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...
  27. ncbi request reprint Automated perfusion-weighted MRI using localized arterial input functions
    Cory 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
    ....
  28. ncbi request reprint Effect of using local arterial input functions on cerebral blood flow estimation
    Cory Lorenz
    Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, Massachusetts, USA
    J Magn Reson Imaging 24:57-65. 2006
    ....
  29. pmc Prediction of early stroke risk in transient symptoms with infarction: relevance to the new tissue-based definition
    E 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...
  30. pmc Age-dependent susceptibility to infarct growth in women
    Figen 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...
  31. ncbi request reprint Creatine kinase-MB elevation after stroke is not cardiac in origin: comparison with troponin T levels
    Hakan 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...
  32. ncbi request reprint 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
  33. ncbi request reprint Diffusion-weighted MRI for the "small stuff": the details of acute cerebral ischaemia
    Achim 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...
  34. ncbi request reprint Hyperhomocysteinemia is associated with the presence of left atrial thrombus in stroke patients with nonvalvular atrial fibrillation
    Hakan 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...
  35. doi request reprint 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...
  36. doi request reprint Statin potentiates human platelet eNOS activity without enhancing eNOS mRNA and protein levels
    Muge 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...
  37. ncbi request reprint Persistence of hyperbaric oxygen-induced oxidative effects after exposure in rat brain cortex tissue
    Hakan 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...
  38. ncbi request reprint Protective effects of exogenously administered or endogenously produced melatonin on hyperbaric oxygen-induced oxidative stress in the rat brain
    Kadir 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...
  39. ncbi request reprint Primary angiitis of the central nervous system and silent cortical hemorrhages
    Hakan 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...
  40. ncbi request reprint Unusually prolonged progressing stroke: an expanding anterior cerebral artery infarction
    Hakan 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...
  41. ncbi request reprint Buerger's disease with multisystem involvement. A case report and a review of the literature
    Meral Calguneri
    Department of Rheumatology, Hacettepe University School of Medicine, Ankara, Turkey
    Angiology 55:325-8. 2004
    ..Therefore, Buerger's disease, although rare, does have a chronic aggressive nature in some patients...
  42. ncbi request reprint Effect of hyperbaric oxygen on flow-mediated vasodilation: an ultrasound study
    Mutlu 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...
  43. ncbi request reprint Echocardiographic predictors of left atrial appendage spontaneous echocontrast in patients with stroke and atrial fibrillation
    Necla 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 Grants2