Functional MR Imaging in Patients with Carotid Artery Stenosis before and after Revascularization

BACKGROUND AND PURPOSE: Significant extracranial stenosis of the ICA is a known risk factor for future stroke and it has been shown that revascularization reduces the risk of future stroke. We applied BOLD fMRI in patients with carotid artery stenosis before and after CEA. Our purpose was to determine whether fMRI is able to demonstrate impaired CVR and to identify patient parameters that are associated with postoperative changes of cerebral hemodynamics. MATERIALS AND METHODS: Nineteen consecutive patients with symptomatic (n = 13) and asymptomatic (n = 6) stenosis of the ICA were prospectively recruited (male/female ratio = 16:3; age, 69 ± 8,1 years). fMRI using a simple bilateral motor task was performed immediately before and after CEA. RESULTS: Mean BOLD MSC was significantly increased postoperatively (MSC, 0.13 ± 0.66; P = 0.0002). Patients with a stenosis of <80% demonstrated an increase in MSC (MSC, 0.32 ± 0.59; P ≤ .0001). Patients with previous ischemic stroke showed a larger MSC than patients with TIAs (stroke: MSC, 0.55 ± 0.65; P ≤ .0001; TIA: MSC, 0.05 ± 0.26; P = 0.054). Patients older than 70 years had a significantly larger MSC following surgery (≤70 years: MSC, −0.01 ± 0.39; P = .429; >70 years: MSC, 0.29 ± 0.48; P ≤ .0001). CONCLUSIONS: BOLD fMRI can demonstrate changes in cerebral hemodynamics before and after CEA, indicative of an ameliorated CVR. This response is dependent on the age of the patient, the degree of preoperative stenosis, and the patient's symptoms.

[1]  S. Ogawa.  Brain magnetic resonance imaging with contrast-dependent oxygenation , 1990 .

[2]  J. Hirsch,et al.  Reperfusion normalizes motor activation patterns in large‐vessel disease , 2009, Annals of neurology.

[3]  T. Benner,et al.  Perfusion-weighted magnetic resonance imaging in patients with carotid artery disease before and after carotid endarterectomy. , 2001, Journal of vascular surgery.

[4]  Sven Haller,et al.  Reduced cerebrovascular reserve at CO2 BOLD MR imaging is associated with increased risk of periinterventional ischemic lesions during carotid endarterectomy or stent placement: preliminary results. , 2008, Radiology.

[5]  H. Tenjin,et al.  Hemodynamic and metabolic changes after carotid endarterectomy in patients with high-degree carotid artery stenosis. , 2005, Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association.

[6]  Darren R Gitelman,et al.  Hemodynamic response changes in cerebrovascular disease: implications for functional MR imaging. , 2002, AJNR. American journal of neuroradiology.

[7]  M. D’Esposito,et al.  Alterations in the BOLD fMRI signal with ageing and disease: a challenge for neuroimaging , 2003, Nature Reviews Neuroscience.

[8]  Randall T Higashida,et al.  Cerebral blood flow changes after endovascular treatment of cerebrovascular stenoses. , 2005, AJNR. American journal of neuroradiology.

[9]  M A Viergever,et al.  Long-term hemodynamic effects of carotid endarterectomy. , 1998, Stroke.

[10]  C. Derouesné,et al.  Internal carotid artery occlusion. A study of 61 instances in 50 patients with post-mortem data. , 1970, Brain : a journal of neurology.

[11]  D. Tank,et al.  Brain magnetic resonance imaging with contrast dependent on blood oxygenation. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[12]  F. X. Guix,et al.  The physiology and pathophysiology of nitric oxide in the brain , 2005, Progress in Neurobiology.

[13]  C. Weiller,et al.  Reduced vasomotor reactivity in cerebral microangiopathy : a study with near-infrared spectroscopy and transcranial Doppler sonography. , 2000, Stroke.

[14]  Hemodynamic Assessment of Carotid Stenosis by Functional Magnetic Resonance Imaging , 2008, Cerebrovascular Diseases.

[15]  I. Wilkinson,et al.  Short-term changes in cerebral microhemodynamics after carotid stenting. , 2003, AJNR. American journal of neuroradiology.

[16]  H. Alkadhi,et al.  Localization of the motor hand area to a knob on the precentral gyrus. A new landmark. , 1997, Brain : a journal of neurology.

[17]  Oliver Speck,et al.  Blood Oxygen Level–Dependent MRI of Cerebral CO2 Reactivity in Severe Carotid Stenosis and Occlusion , 2005, Stroke.

[18]  Endarterectomy for asymptomatic carotid artery stenosis. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. , 1995, JAMA.

[19]  C. Warlow,et al.  MRC European Carotid Surgery Trial: interim results for symptomatic patients with severe (70-99%) or with mild (0-29%) carotid stenosis , 1991, The Lancet.

[20]  H. Kugel,et al.  Age related signal decrease in functional magnetic resonance imaging during motor stimulation in humans , 2001, Neuroscience Letters.

[21]  M. Hennerici,et al.  Is Hypoperfusion an Important Cause of Strokes? If So, How? , 2006, Cerebrovascular Diseases.

[22]  V. Prabhakaran,et al.  Neural Substrates of Word Generation during Stroke Recovery: The Influence of Cortical Hypoperfusion , 2007, Behavioural neurology.

[23]  C. Caltagirone,et al.  Transcranial Doppler assessment of cerebrovascular reactivity in symptomatic and asymptomatic severe carotid stenosis. , 1996, Stroke.

[24]  David J Mikulis,et al.  Mapping Cerebrovascular Reactivity Using Blood Oxygen Level-Dependent MRI in Patients With Arterial Steno-occlusive Disease: Comparison With Arterial Spin Labeling MRI , 2008, Stroke.

[25]  M. Raichle,et al.  The effect of hemodynamically significant carotid artery disease on the hemodynamic status of the cerebral circulation. , 1987, Annals of internal medicine.

[26]  K Willmes,et al.  Determination of cognitive hemispheric lateralization by "functional" transcranial Doppler cross-validated by functional MRI. , 1999, Stroke.

[27]  A. Fox,et al.  How to measure carotid stenosis. , 1993, Radiology.

[28]  D. Rossi,et al.  Astrocyte metabolism and signaling during brain ischemia , 2007, Nature Neuroscience.

[29]  L. Kappelle,et al.  Sustained Bilateral Hemodynamic Benefit of Contralateral Carotid Endarterectomy in Patients With Symptomatic Internal Carotid Artery Occlusion , 2001, Stroke.

[30]  G. Sicard.  MRC European Carotid Surgery Trial: interim results for symptomatic patients with severe (70–99%) or mild (0–29%) carotid stenosis: European Carotid Surgery Trialist' Collaborative Group. Lancet 1991;337:1235-43 , 1992 .

[31]  D. Sackett,et al.  Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. , 1991, The New England journal of medicine.

[32]  J. Talairach,et al.  Co-Planar Stereotaxic Atlas of the Human Brain: 3-Dimensional Proportional System: An Approach to Cerebral Imaging , 1988 .

[33]  John W Krakauer,et al.  Hypoperfusion without stroke alters motor activation in the opposite hemisphere , 2004, Annals of neurology.

[34]  P Mansfield,et al.  Real-time echo-planar imaging by NMR. , 1984, British medical bulletin.

[35]  P M Matthews,et al.  Altered Hemodynamic Responses in Patients After Subcortical Stroke Measured by Functional MRI , 2002, Stroke.

[36]  A. Davies,et al.  Endarterectomy for asymptomatic carotid artery stenosis , 1995, BMJ.

[37]  Iraj Derakhshan.  Impaired hemodynamics and neural activation? A fMRI study of major cerebral artery stenosis , 2004, Neurology.

[38]  R. Turner,et al.  Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[39]  B. MacVicar,et al.  Astrocyte control of the cerebrovasculature , 2007, Glia.