Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Neuroimaging of acute ischemic stroke

Jamary Oliveira Filho, MD, MS, PhD
Section Editors
Scott E Kasner, MD
Eric D Schwartz, MD
Deputy Editor
John F Dashe, MD, PhD


Imaging studies are used to exclude hemorrhage in the acute stroke patient, to assess the degree of brain injury, and to identify the vascular lesion responsible for the ischemic deficit. Some advanced CT and MRI technologies are able to distinguish between brain tissue that is irreversibly infarcted and that which is potentially salvageable, thereby allowing better selection of patients likely to benefit from therapy. The use of this technology is dependent upon availability, and its role in guiding treatment decisions is still under study.

Neuroimaging during the acute phase (first few hours) of an ischemic stroke will be reviewed here. Other aspects of the acute evaluation of stroke, the clinical diagnosis of various types of stroke, and the subacute and long-term assessment of patients who have had a stroke are discussed separately. (See "Initial assessment and management of acute stroke" and "Clinical diagnosis of stroke subtypes" and "Overview of the evaluation of stroke".)


The main advantages of CT are widespread access and speed of acquisition. In the hyperacute phase, a noncontrast CT (NCCT) scan is usually ordered to exclude or confirm hemorrhage; it is highly sensitive for this indication. A NCCT scan should be obtained as soon as the patient is medically stable. The presence of hemorrhage leads to very different management and concerns than a normal scan or one that shows infarction. Immediate CT scanning of all patients with suspected stroke is also the most cost-effective strategy when compared with alternate strategies such as scanning selected patients or delayed rather than immediate imaging [1].

The utility of CT for acute stroke has been enhanced by the advent of additional CT techniques including CT perfusion imaging (CTP) and CT angiography (CTA). Multimodal CT evaluation that employs the three techniques (NCCT, CTA, and CTP) combined shows improved detection of acute infarction when compared with NCCT evaluation alone [2-5]. In addition, multimodal evaluation that includes CTA and CTP may permit assessment of the site of vascular occlusion, infarct core, salvageable brain tissue and degree of collateral circulation [6,7].

Early signs of infarction on noncontrast CT — The sensitivity of standard noncontrast CT for brain ischemia increases after 24 hours. However, in a systematic review involving 15 studies where CT scans were performed within six hours of stroke onset, the prevalence of early CT signs of brain infarction was 61 percent (standard deviation +/- 21 percent) [8].

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Apr 04, 2016.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Wardlaw JM, Seymour J, Cairns J, et al. Immediate computed tomography scanning of acute stroke is cost-effective and improves quality of life. Stroke 2004; 35:2477.
  2. Ezzeddine MA, Lev MH, McDonald CT, et al. CT angiography with whole brain perfused blood volume imaging: added clinical value in the assessment of acute stroke. Stroke 2002; 33:959.
  3. Kloska SP, Nabavi DG, Gaus C, et al. Acute stroke assessment with CT: do we need multimodal evaluation? Radiology 2004; 233:79.
  4. Hopyan J, Ciarallo A, Dowlatshahi D, et al. Certainty of stroke diagnosis: incremental benefit with CT perfusion over noncontrast CT and CT angiography. Radiology 2010; 255:142.
  5. Campbell BC, Weir L, Desmond PM, et al. CT perfusion improves diagnostic accuracy and confidence in acute ischaemic stroke. J Neurol Neurosurg Psychiatry 2013; 84:613.
  6. Tan JC, Dillon WP, Liu S, et al. Systematic comparison of perfusion-CT and CT-angiography in acute stroke patients. Ann Neurol 2007; 61:533.
  7. Wintermark M, Rowley HA, Lev MH. Acute stroke triage to intravenous thrombolysis and other therapies with advanced CT or MR imaging: pro CT. Radiology 2009; 251:619.
  8. Wardlaw JM, Mielke O. Early signs of brain infarction at CT: observer reliability and outcome after thrombolytic treatment--systematic review. Radiology 2005; 235:444.
  9. Truwit CL, Barkovich AJ, Gean-Marton A, et al. Loss of the insular ribbon: another early CT sign of acute middle cerebral artery infarction. Radiology 1990; 176:801.
  10. von Kummer R, Meyding-Lamadé U, Forsting M, et al. Sensitivity and prognostic value of early CT in occlusion of the middle cerebral artery trunk. AJNR Am J Neuroradiol 1994; 15:9.
  11. Marks MP, Holmgren EB, Fox AJ, et al. Evaluation of early computed tomographic findings in acute ischemic stroke. Stroke 1999; 30:389.
  12. Wijdicks EF, Diringer MN. Middle cerebral artery territory infarction and early brain swelling: progression and effect of age on outcome. Mayo Clin Proc 1998; 73:829.
  13. Leys D, Pruvo JP, Godefroy O, et al. Prevalence and significance of hyperdense middle cerebral artery in acute stroke. Stroke 1992; 23:317.
  14. Patel SC, Levine SR, Tilley BC, et al. Lack of clinical significance of early ischemic changes on computed tomography in acute stroke. JAMA 2001; 286:2830.
  15. Hacke W, Kaste M, Fieschi C, et al. Intravenous thrombolysis with recombinant tissue plasminogen activator for acute hemispheric stroke. The European Cooperative Acute Stroke Study (ECASS). JAMA 1995; 274:1017.
  16. Wardlaw JM, Dorman PJ, Lewis SC, Sandercock PA. Can stroke physicians and neuroradiologists identify signs of early cerebral infarction on CT? J Neurol Neurosurg Psychiatry 1999; 67:651.
  17. von Kummer R, Bourquain H, Bastianello S, et al. Early prediction of irreversible brain damage after ischemic stroke at CT. Radiology 2001; 219:95.
  18. Lev MH, Farkas J, Gemmete JJ, et al. Acute stroke: improved nonenhanced CT detection--benefits of soft-copy interpretation by using variable window width and center level settings. Radiology 1999; 213:150.
  19. Barber PA, Demchuk AM, Zhang J, Buchan AM. Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy. ASPECTS Study Group. Alberta Stroke Programme Early CT Score. Lancet 2000; 355:1670.
  20. Pexman JH, Barber PA, Hill MD, et al. Use of the Alberta Stroke Program Early CT Score (ASPECTS) for assessing CT scans in patients with acute stroke. AJNR Am J Neuroradiol 2001; 22:1534.
  21. Coutts SB, Demchuk AM, Barber PA, et al. Interobserver variation of ASPECTS in real time. Stroke 2004; 35:e103.
  22. Barber PA, Hill MD, Eliasziw M, et al. Imaging of the brain in acute ischaemic stroke: comparison of computed tomography and magnetic resonance diffusion-weighted imaging. J Neurol Neurosurg Psychiatry 2005; 76:1528.
  23. Hill MD, Rowley HA, Adler F, et al. Selection of acute ischemic stroke patients for intra-arterial thrombolysis with pro-urokinase by using ASPECTS. Stroke 2003; 34:1925.
  24. Hill MD, Buchan AM, Canadian Alteplase for Stroke Effectiveness Study (CASES) Investigators. Thrombolysis for acute ischemic stroke: results of the Canadian Alteplase for Stroke Effectiveness Study. CMAJ 2005; 172:1307.
  25. Demchuk AM, Hill MD, Barber PA, et al. Importance of early ischemic computed tomography changes using ASPECTS in NINDS rtPA Stroke Study. Stroke 2005; 36:2110.
  26. Dzialowski I, Hill MD, Coutts SB, et al. Extent of early ischemic changes on computed tomography (CT) before thrombolysis: prognostic value of the Alberta Stroke Program Early CT Score in ECASS II. Stroke 2006; 37:973.
  27. Na DG, Kim EY, Ryoo JW, et al. CT sign of brain swelling without concomitant parenchymal hypoattenuation: comparison with diffusion- and perfusion-weighted MR imaging. Radiology 2005; 235:992.
  28. Butcher KS, Lee SB, Parsons MW, et al. Differential prognosis of isolated cortical swelling and hypoattenuation on CT in acute stroke. Stroke 2007; 38:941.
  29. Coutts SB, Lev MH, Eliasziw M, et al. ASPECTS on CTA source images versus unenhanced CT: added value in predicting final infarct extent and clinical outcome. Stroke 2004; 35:2472.
  30. Parsons MW, Pepper EM, Chan V, et al. Perfusion computed tomography: prediction of final infarct extent and stroke outcome. Ann Neurol 2005; 58:672.
  31. Latchaw RE, Alberts MJ, Lev MH, et al. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association. Stroke 2009; 40:3646.
  32. Menon BK, d'Esterre CD, Qazi EM, et al. Multiphase CT Angiography: A New Tool for the Imaging Triage of Patients with Acute Ischemic Stroke. Radiology 2015; 275:510.
  33. Goyal M, Demchuk AM, Menon BK, et al. Randomized assessment of rapid endovascular treatment of ischemic stroke. N Engl J Med 2015; 372:1019.
  34. Hunter GJ, Hamberg LM, Ponzo JA, et al. Assessment of cerebral perfusion and arterial anatomy in hyperacute stroke with three-dimensional functional CT: early clinical results. AJNR Am J Neuroradiol 1998; 19:29.
  35. Lev MH, Segal AZ, Farkas J, et al. Utility of perfusion-weighted CT imaging in acute middle cerebral artery stroke treated with intra-arterial thrombolysis: prediction of final infarct volume and clinical outcome. Stroke 2001; 32:2021.
  36. Schramm P, Schellinger PD, Fiebach JB, et al. Comparison of CT and CT angiography source images with diffusion-weighted imaging in patients with acute stroke within 6 hours after onset. Stroke 2002; 33:2426.
  37. Camargo EC, Furie KL, Singhal AB, et al. Acute brain infarct: detection and delineation with CT angiographic source images versus nonenhanced CT scans. Radiology 2007; 244:541.
  38. Wintermark M, Reichhart M, Cuisenaire O, et al. Comparison of admission perfusion computed tomography and qualitative diffusion- and perfusion-weighted magnetic resonance imaging in acute stroke patients. Stroke 2002; 33:2025.
  39. Allmendinger AM, Tang ER, Lui YW, Spektor V. Imaging of stroke: Part 1, Perfusion CT--overview of imaging technique, interpretation pearls, and common pitfalls. AJR Am J Roentgenol 2012; 198:52.
  40. Heit JJ, Wintermark M. Perfusion Computed Tomography for the Evaluation of Acute Ischemic Stroke: Strengths and Pitfalls. Stroke 2016; 47:1153.
  41. Goyal M, Menon BK, Derdeyn CP. Perfusion imaging in acute ischemic stroke: let us improve the science before changing clinical practice. Radiology 2013; 266:16.
  42. Lev MH. Perfusion imaging of acute stroke: its role in current and future clinical practice. Radiology 2013; 266:22.
  43. Michel P, Bogousslavsky J. Penumbra is brain: no excuse not to perfuse. Ann Neurol 2005; 58:661.
  44. Köhrmann M, Schellinger PD. Acute stroke triage to intravenous thrombolysis and other therapies with advanced CT or MR imaging: pro MR imaging. Radiology 2009; 251:627.
  45. Patel MR, Edelman RR, Warach S. Detection of hyperacute primary intraparenchymal hemorrhage by magnetic resonance imaging. Stroke 1996; 27:2321.
  46. Fiebach JB, Schellinger PD, Gass A, et al. Stroke magnetic resonance imaging is accurate in hyperacute intracerebral hemorrhage: a multicenter study on the validity of stroke imaging. Stroke 2004; 35:502.
  47. Kidwell CS, Chalela JA, Saver JL, et al. Comparison of MRI and CT for detection of acute intracerebral hemorrhage. JAMA 2004; 292:1823.
  48. Kang DW, Chalela JA, Dunn W, et al. MRI screening before standard tissue plasminogen activator therapy is feasible and safe. Stroke 2005; 36:1939.
  49. Ringelstein EB. Ultrafast magnetic resonance imaging protocols in stroke. J Neurol Neurosurg Psychiatry 2005; 76:905.
  50. U-King-Im JM, Trivedi RA, Graves MJ, et al. Utility of an ultrafast magnetic resonance imaging protocol in recent and semi-recent strokes. J Neurol Neurosurg Psychiatry 2005; 76:1002.
  51. Warach S, Gaa J, Siewert B, et al. Acute human stroke studied by whole brain echo planar diffusion-weighted magnetic resonance imaging. Ann Neurol 1995; 37:231.
  52. Sorensen AG, Buonanno FS, Gonzalez RG, et al. Hyperacute stroke: evaluation with combined multisection diffusion-weighted and hemodynamically weighted echo-planar MR imaging. Radiology 1996; 199:391.
  53. Li F, Han S, Tatlisumak T, et al. A new method to improve in-bore middle cerebral artery occlusion in rats: demonstration with diffusion- and perfusion-weighted imaging. Stroke 1998; 29:1715.
  54. Beauchamp NJ Jr, Barker PB, Wang PY, vanZijl PC. Imaging of acute cerebral ischemia. Radiology 1999; 212:307.
  55. Schlaug G, Siewert B, Benfield A, et al. Time course of the apparent diffusion coefficient (ADC) abnormality in human stroke. Neurology 1997; 49:113.
  56. González RG, Schaefer PW, Buonanno FS, et al. Diffusion-weighted MR imaging: diagnostic accuracy in patients imaged within 6 hours of stroke symptom onset. Radiology 1999; 210:155.
  57. Fiebach JB, Schellinger PD, Jansen O, et al. CT and diffusion-weighted MR imaging in randomized order: diffusion-weighted imaging results in higher accuracy and lower interrater variability in the diagnosis of hyperacute ischemic stroke. Stroke 2002; 33:2206.
  58. Chalela JA, Kidwell CS, Nentwich LM, et al. Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison. Lancet 2007; 369:293.
  59. Brazzelli M, Sandercock PA, Chappell FM, et al. Magnetic resonance imaging versus computed tomography for detection of acute vascular lesions in patients presenting with stroke symptoms. Cochrane Database Syst Rev 2009; :CD007424.
  60. Brunser AM, Hoppe A, Illanes S, et al. Accuracy of diffusion-weighted imaging in the diagnosis of stroke in patients with suspected cerebral infarct. Stroke 2013; 44:1169.
  61. Simonsen CZ, Madsen MH, Schmitz ML, et al. Sensitivity of diffusion- and perfusion-weighted imaging for diagnosing acute ischemic stroke is 97.5%. Stroke 2015; 46:98.
  62. Ay H, Buonanno FS, Rordorf G, et al. Normal diffusion-weighted MRI during stroke-like deficits. Neurology 1999; 52:1784.
  63. Sylaja PN, Coutts SB, Krol A, et al. When to expect negative diffusion-weighted images in stroke and transient ischemic attack. Stroke 2008; 39:1898.
  64. Kuhl CK, Textor J, Gieseke J, et al. Acute and subacute ischemic stroke at high-field-strength (3.0-T) diffusion-weighted MR imaging: intraindividual comparative study. Radiology 2005; 234:509.
  65. Rosso C, Drier A, Lacroix D, et al. Diffusion-weighted MRI in acute stroke within the first 6 hours: 1.5 or 3.0 Tesla? Neurology 2010; 74:1946.
  66. Hunsche S, Moseley ME, Stoeter P, Hedehus M. Diffusion-tensor MR imaging at 1.5 and 3.0 T: initial observations. Radiology 2001; 221:550.
  67. Schellinger PD, Bryan RN, Caplan LR, et al. Evidence-based guideline: The role of diffusion and perfusion MRI for the diagnosis of acute ischemic stroke: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2010; 75:177.
  68. Makin SD, Doubal FN, Dennis MS, Wardlaw JM. Clinically Confirmed Stroke With Negative Diffusion-Weighted Imaging Magnetic Resonance Imaging: Longitudinal Study of Clinical Outcomes, Stroke Recurrence, and Systematic Review. Stroke 2015; 46:3142.
  69. Schulz UG, Briley D, Meagher T, et al. Diffusion-weighted MRI in 300 patients presenting late with subacute transient ischemic attack or minor stroke. Stroke 2004; 35:2459.
  70. Kang DW, Latour LL, Chalela JA, et al. Early ischemic lesion recurrence within a week after acute ischemic stroke. Ann Neurol 2003; 54:66.
  71. Wen HM, Lam WW, Rainer T, et al. Multiple acute cerebral infarcts on diffusion-weighted imaging and risk of recurrent stroke. Neurology 2004; 63:1317.
  72. Coutts SB, Hill MD, Simon JE, et al. Silent ischemia in minor stroke and TIA patients identified on MR imaging. Neurology 2005; 65:513.
  73. Sylaja PN, Coutts SB, Subramaniam S, et al. Acute ischemic lesions of varying ages predict risk of ischemic events in stroke/TIA patients. Neurology 2007; 68:415.
  74. Chalela JA, Alsop DC, Gonzalez-Atavales JB, et al. Magnetic resonance perfusion imaging in acute ischemic stroke using continuous arterial spin labeling. Stroke 2000; 31:680.
  75. Donnan GA, Baron JC, Ma H, Davis SM. Penumbral selection of patients for trials of acute stroke therapy. Lancet Neurol 2009; 8:261.
  76. Sobesky J, Zaro Weber O, Lehnhardt FG, et al. Does the mismatch match the penumbra? Magnetic resonance imaging and positron emission tomography in early ischemic stroke. Stroke 2005; 36:980.
  77. Kranz PG, Eastwood JD. Does diffusion-weighted imaging represent the ischemic core? An evidence-based systematic review. AJNR Am J Neuroradiol 2009; 30:1206.
  78. Labeyrie MA, Turc G, Hess A, et al. Diffusion lesion reversal after thrombolysis: a MR correlate of early neurological improvement. Stroke 2012; 43:2986.
  79. Ogata T, Nagakane Y, Christensen S, et al. A topographic study of the evolution of the MR DWI/PWI mismatch pattern and its clinical impact: a study by the EPITHET and DEFUSE Investigators. Stroke 2011; 42:1596.
  80. Ma H, Zavala JA, Teoh H, et al. Fragmentation of the classical magnetic resonance mismatch "penumbral" pattern with time. Stroke 2009; 40:3752.
  81. Olivot JM, Mlynash M, Thijs VN, et al. Geography, structure, and evolution of diffusion and perfusion lesions in Diffusion and perfusion imaging Evaluation For Understanding Stroke Evolution (DEFUSE). Stroke 2009; 40:3245.
  82. Latchaw RE, Yonas H, Hunter GJ, et al. Guidelines and recommendations for perfusion imaging in cerebral ischemia: A scientific statement for healthcare professionals by the writing group on perfusion imaging, from the Council on Cardiovascular Radiology of the American Heart Association. Stroke 2003; 34:1084.
  83. Hjort N, Butcher K, Davis SM, et al. Magnetic resonance imaging criteria for thrombolysis in acute cerebral infarct. Stroke 2005; 36:388.
  84. Neumann-Haefelin T, Wittsack HJ, Wenserski F, et al. Diffusion- and perfusion-weighted MRI. The DWI/PWI mismatch region in acute stroke. Stroke 1999; 30:1591.
  85. Sorensen AG, Copen WA, Ostergaard L, et al. Hyperacute stroke: simultaneous measurement of relative cerebral blood volume, relative cerebral blood flow, and mean tissue transit time. Radiology 1999; 210:519.
  86. Rordorf G, Koroshetz WJ, Copen WA, et al. Regional ischemia and ischemic injury in patients with acute middle cerebral artery stroke as defined by early diffusion-weighted and perfusion-weighted MRI. Stroke 1998; 29:939.
  87. Beaulieu C, de Crespigny A, Tong DC, et al. Longitudinal magnetic resonance imaging study of perfusion and diffusion in stroke: evolution of lesion volume and correlation with clinical outcome. Ann Neurol 1999; 46:568.
  88. Lövblad KO. Diffusion-weighted MRI: back to the future. Stroke 2002; 33:2204.
  89. Chalela JA, Kang DW, Luby M, et al. Early magnetic resonance imaging findings in patients receiving tissue plasminogen activator predict outcome: Insights into the pathophysiology of acute stroke in the thrombolysis era. Ann Neurol 2004; 55:105.
  90. Albers GW, Thijs VN, Wechsler L, et al. Magnetic resonance imaging profiles predict clinical response to early reperfusion: the diffusion and perfusion imaging evaluation for understanding stroke evolution (DEFUSE) study. Ann Neurol 2006; 60:508.
  91. Schellinger PD, Thomalla G, Fiehler J, et al. MRI-based and CT-based thrombolytic therapy in acute stroke within and beyond established time windows: an analysis of 1210 patients. Stroke 2007; 38:2640.
  92. Bykowski JL, Latour LL, Warach S. More accurate identification of reversible ischemic injury in human stroke by cerebrospinal fluid suppressed diffusion-weighted imaging. Stroke 2004; 35:1100.
  93. Lee LJ, Kidwell CS, Alger J, et al. Impact on stroke subtype diagnosis of early diffusion-weighted magnetic resonance imaging and magnetic resonance angiography. Stroke 2000; 31:1081.
  94. Pedraza S, Silva Y, Mendez J, et al. Comparison of preperfusion and postperfusion magnetic resonance angiography in acute stroke. Stroke 2004; 35:2105.
  95. Flacke S, Urbach H, Keller E, et al. Middle cerebral artery (MCA) susceptibility sign at susceptibility-based perfusion MR imaging: clinical importance and comparison with hyperdense MCA sign at CT. Radiology 2000; 215:476.
  96. Rovira A, Orellana P, Alvarez-Sabín J, et al. Hyperacute ischemic stroke: middle cerebral artery susceptibility sign at echo-planar gradient-echo MR imaging. Radiology 2004; 232:466.
  97. Greer DM, Koroshetz WJ, Cullen S, et al. Magnetic resonance imaging improves detection of intracerebral hemorrhage over computed tomography after intra-arterial thrombolysis. Stroke 2004; 35:491.
  98. Molina CA, Saver JL. Extending reperfusion therapy for acute ischemic stroke: emerging pharmacological, mechanical, and imaging strategies. Stroke 2005; 36:2311.
  99. Shah S, Luby M, Poole K, et al. Screening with MRI for Accurate and Rapid Stroke Treatment: SMART. Neurology 2015; 84:2438.
  100. Sølling C, Ashkanian M, Hjort N, et al. Feasibility and logistics of MRI before thrombolytic treatment. Acta Neurol Scand 2009; 120:143.
  101. Schramm P, Schellinger PD, Klotz E, et al. Comparison of perfusion computed tomography and computed tomography angiography source images with perfusion-weighted imaging and diffusion-weighted imaging in patients with acute stroke of less than 6 hours' duration. Stroke 2004; 35:1652.
  102. Grolimund P, Seiler RW, Aaslid R, et al. Evaluation of cerebrovascular disease by combined extracranial and transcranial Doppler sonography. Experience in 1,039 patients. Stroke 1987; 18:1018.
  103. Camerlingo M, Casto L, Censori B, et al. Transcranial Doppler in acute ischemic stroke of the middle cerebral artery territories. Acta Neurol Scand 1993; 88:108.
  104. Iannuzzi A, Wilcosky T, Mercuri M, et al. Ultrasonographic correlates of carotid atherosclerosis in transient ischemic attack and stroke. Stroke 1995; 26:614.
  105. Razumovsky AY, Gillard JH, Bryan RN, et al. TCD, MRA and MRI in acute cerebral ischemia. Acta Neurol Scand 1999; 99:65.
  106. Alexandrov AV, Demchuk AM, Wein TH, Grotta JC. Yield of transcranial Doppler in acute cerebral ischemia. Stroke 1999; 30:1604.
  107. Gao S, Wong KS, Hansberg T, et al. Microembolic signal predicts recurrent cerebral ischemic events in acute stroke patients with middle cerebral artery stenosis. Stroke 2004; 35:2832.
  108. Saqqur M, Shuaib A, Alexandrov AV, et al. Derivation of transcranial Doppler criteria for rescue intra-arterial thrombolysis: multicenter experience from the Interventional Management of Stroke study. Stroke 2005; 36:865.
  109. Chernyshev OY, Garami Z, Calleja S, et al. Yield and accuracy of urgent combined carotid/transcranial ultrasound testing in acute cerebral ischemia. Stroke 2005; 36:32.
  110. Dion JE, Gates PC, Fox AJ, et al. Clinical events following neuroangiography: a prospective study. Stroke 1987; 18:997.
  111. Waugh JR, Sacharias N. Arteriographic complications in the DSA era. Radiology 1992; 182:243.
  112. Heiserman JE, Dean BL, Hodak JA, et al. Neurologic complications of cerebral angiography. AJNR Am J Neuroradiol 1994; 15:1401.
  113. Johnston DC, Chapman KM, Goldstein LB. Low rate of complications of cerebral angiography in routine clinical practice. Neurology 2001; 57:2012.
  114. Willinsky RA, Taylor SM, TerBrugge K, et al. Neurologic complications of cerebral angiography: prospective analysis of 2,899 procedures and review of the literature. Radiology 2003; 227:522.
  115. Kaufmann TJ, Huston J 3rd, Mandrekar JN, et al. Complications of diagnostic cerebral angiography: evaluation of 19,826 consecutive patients. Radiology 2007; 243:812.
  116. Bendszus M, Koltzenburg M, Burger R, et al. Silent embolism in diagnostic cerebral angiography and neurointerventional procedures: a prospective study. Lancet 1999; 354:1594.
  117. Kato K, Tomura N, Takahashi S, et al. Ischemic lesions related to cerebral angiography: Evaluation by diffusion weighted MR imaging. Neuroradiology 2003; 45:39.
  118. Bendszus M, Koltzenburg M, Bartsch AJ, et al. Heparin and air filters reduce embolic events caused by intra-arterial cerebral angiography: a prospective, randomized trial. Circulation 2004; 110:2210.
  119. Jauch EC, Saver JL, Adams HP Jr, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013; 44:870.