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

M Schaaf,T Krings,G Mommertz,M Das,G Mühlenbruch,A Ludolph,S Geibprasert

doi:10.3174/ajnr.a2219

M Schaaf, T Krings + Show 5 more

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https://doi.org/10.3174/ajnr.a2219

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Abstract

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. 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. 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). 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.

Highlights

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
A significant increase in BOLD SC in the primary motor cortex of the hemisphere supplied by the ICA that underwent surgery was noted in the group of 19 patients as a whole (MSC, 0.13% Ϯ 0.66, P ϭ .0002) (Fig 1), while there was no significant change noted in the contralateral hemisphere
The following subset analyses of the dependency of the postoperative increase in MR imaging SC were performed to further evaluate which factors were related to the degree of MR imaging signalintensity increase: 1) degree of stenosis, 2) age, and 3) symptomatic-versus-asymptomatic patients (Table 2)

Summary

Objectives

The aim of this study was to determine whether BOLD fMRI can demonstrate impaired CVR during a bimanual motor task and detect postoperative improvement or restoration of an impaired BOLD response

Methods

Results

Discussion

Conclusion