FMRI of the auditory cortex in patients with unilateral carotid artery steno-occlusive disease.

Abstract

To examine whether an internal carotid artery (ICA) steno-occlusive disease leads to a reduced blood oxygenation level dependent (BOLD)-signal change due to a decreased vasodilatory reserve capacity. Patients suffering from unilateral ICA stenosis or occlusion were examined using functional magnetic resonance imaging (fMRI) of the auditory cortex with a bilateral stimulation applying a pulsed 1000 Hz sine-tone. Compared to control subjects, who showed symmetric bilateral BOLD-responses within the auditory cortex, the ICA patients revealed either a normal bilateral cortical activation pattern or a reduced cortical activation on the steno-occluded side. This latter decrease of BOLD-signal change might indicate a depressed vasomotor reserve capacity. The observed coincidence between this asymmetric reduction in BOLD-signal and ischemic borderzone lesions on the affected side in this subgroup of patients strongly supports this assumption. This study shows that fMRI of the auditory cortex appears to have clinical merit in the workup of cerebrovascular conditions.