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NEUROLOGY 2009;72:643-649
© 2009 American Academy of Neurology

Vasoreactivity and peri-infarct hyperintensities in stroke

P. Zhao, PhD, D. C. Alsop, PhD, A. AbdulJalil, PhD, M. Selim, MD, L. Lipsitz, MD, P. Novak, MD, PhD, L. Caplan, MD, K. Hu, PhD and V. Novak, MD, PhD

From the Departments of Medicine (P.Z., K.H., V.N.), Radiology (D.C.A.), and Neurology (M.S., L.C.), Beth Israel Deaconess Medical Center, Boston; Department of Radiology (A.A.), Ohio State University, Columbus; Institute for Aging Research (L.L.), Hebrew SeniorLife, Boston, MA; and Department of Neurology (P.N.), University of Massachusetts, Boston.

Address correspondence and reprint requests to Dr. Vera Novak, Division of Gerontology, Beth Israel Deaconess Medical Center, 110 Francis Street, Boston, MA 02215 vnovak{at}bidmc.harvard.edu

Objective: It is unknown if impaired cerebral vasoreactivity recovers after ischemic stroke, and whether it compromises perfusion in regions surrounding infarct and other vascular territories. We investigated the regional differences in CO2 vasoreactivity (CO2VR) and their relationships to peri-infarct T2 hyperintensities (PIHs), chronic infarct volumes, and clinical outcomes.

Methods: We studied 39 subjects with chronic large middle cerebral artery territory infarcts and 48 matched controls. Anatomic and three-dimensional continuous arterial spin labeling imaging at 3-Tesla MRI were used to measure regional cerebral blood flow (CBF) and CO2VR during normocapnia, hypercapnia, and hypocapnia in main arteries distributions.

Results: Stroke patients showed a significantly lower augmentation of blood flow at increased CO2 but greater reduction of blood flow with decreased CO2 than the control group. This altered vasoregulatory response was observed both ipsilateral and contralateral to the stroke. Lower CO2VR on the stroke side was associated with PIHs, greater infarct volume, and worse outcomes. The cases with PIHs (n = 27) had lower CBF during all conditions bilaterally (p < 0.0001) compared to cases with infarct only.

Conclusions: Perfusion augmentation is inadequate in multiple vascular territories in patients with large artery ischemic infarcts, but vasoconstriction is preserved. Peri-infarct T2 hyperintensities are associated with lower blood flow. Strategies aimed to preserve vasoreactivity after an ischemic stroke should be tested for their effect on long-term outcomes.

Abbreviations: ACA = anterior cerebral artery; ADC = apparent diffusion coefficient; BP = blood pressure; CASL = continuous arterial spin labeling; CBF = cerebral blood flow; CO2VR = CO2 vasoreactivity; DWI = diffusion-weighted image; FLAIR = fluid-attenuated inversion recovery; FOV = field of view; GM = gray matter; LDL = low-density lipoprotein; MCA = middle cerebral artery; MP-RAGE = magnetization prepared rapid gradient echo; mRS = modified Rankin Scale; NIHSS = NIH Stroke Scale; PCA = posterior cerebral artery; PIHs = peri-infarct T2 hyperintensities; TE = echo time; TI = inversion time; TR = repetition time; WBC = white blood cell; WM = white matter.

Supported by American Diabetes Association 1-06-CR-25, NIH-National Institute of Neurological Disorders and Stroke R01-NS045745, NIH-National Institute of Neurological Disorders and Stroke STTR 1R41NS053128-01A2 grants to V. Novak; an NIH Older American Independence Center Grant 2P60 AG08812 and NIH Program Project P01-AG004390 to L. Lipsitz; and a General Clinical Research Center (GCRC) Grant MO1-RR01302. Dr. Lipsitz holds the Irving and Edyth S. Usen and Family Chair in Geriatric Medicine at Hebrew SeniorLife.

Disclosure: The authors report no disclosures.

Received June 20, 2008. Accepted in final form November 17, 2008.






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