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

Purpose: 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. Materials and Methods: 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. Results: 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 vasomator 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. Conclusion: This study shows that fMRI of the auditory cortex appears to have clinical merit in the workup of cerebrovascular conditions.