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Reduced Cerebrovascular Reserve at CO₂ BOLD MR Imaging Is Associated with Increased Risk of Periinterventional Ischemic Lesions during Carotid Endarterectomy or Stent Placement: Preliminary Results¹

¹ From the Department of Diagnostic and Interventional Neuroradiology, Institute of Radiology (S.H., S.G.W.), Department of Diagnostic Radiology, Institute of Radiology (S.H., D.B.), Institute of Neurology (L.H.B., P.A.L., S.T.E.), and Division of Radiological Physics, Institute of Radiology (M.K.), University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland; Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany (J.R.); and Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany (O.S.). Received September 18, 2007; revision requested January 4, 2008; revision received January 29; accepted April 11; final version accepted April 21. S.T.E., as principal investigator, supported by a grant from the Mach-Gaensslen-[Stiftung]-Foundation, a noncommercial fund. This foundation had no influence on design, analysis, or interpretation of the data. L.H.B. supported in part by a grant from the Swiss National Science Foundation (PBBSB-116873). S.G.W. supported in part by grants from the Swiss National Science Foundation (3200-066634 and 320000-113492). Address correspondence to S.H. (e-mail: shaller{at}uhbs.ch).

Purpose: To determine whether any initial reductions in cardiovascular reserve (CVR) normalize after carotid revascularization and—because reduced CVR represents a risk factor for ischemic events—whether patients who develop periinterventional infarction have more severely reduced pretreatment CVR than those who do not.

Materials and Methods: Ethics committee approval and informed consent were obtained. Twenty-four consecutive patients with symptomatic high-grade internal carotid artery stenosis (seven women; mean age, 73.1 years ± 9.4 [standard deviation]) were recruited from a prospective, randomized trial that compared carotid artery stent placement with endarterectomy. Magnetic resonance (MR) imaging, including CO₂ blood oxygen level–dependent (BOLD) MR, was performed 1–3 days before, 1–3 days after, and 1 month after carotid revascularization (carotid artery stent placement, n = 13; carotid endarterectomy, n = 11).

Results: Mean CVR in the ipsilateral middle cerebral artery (MCA) territory was reduced prior to treatment (mean T2* in ipsilateral territory, 1.92% ± 1.18; mean T2* in contralateral territory, 2.28% ± 1.15 [P < .05]) and normalized after treatment (mean T2* 1–3 days after treatment in ipsilateral territory, 2.66% ± 1.01; that in contralateral territory, 2.48% ± 1.27 [P > .05]; mean T2* 1 month after treatment in ipsilateral territory, 2.27% ± 1.05; that in contralateral territory, 2.14% ± 0.96 [P > .05]). Those patients who developed new periinterventional infarcts (n = 7 with punctate foci of restricted diffusion) had greater reduction of CVR in the ipsilateral MCA territory prior to treatment (relative reduction, 32.5% ± 46.0; P < .05) than those who did not develop infarction (n = 17; relative reduction, 9.2% ± 55.9).

Conclusion: CO₂ BOLD MR imaging could be used successfully to monitor the hemodynamic effects of carotid revascularization; initial reductions in CVR normalized after carotid revascularization. Severely reduced pretreatment CVR was associated with increased occurrence of new periinterventional therapy infarction.

© RSNA, 2008