Short-term changes in cerebral microhemodynamics after carotid stenting.

BACKGROUND AND PURPOSE: The cerebral hemodynamic sequelae of interventions in patients with severe internal carotid artery (ICA) stenoses are not fully understood. In this study, we sought to determine the immediate changes in cerebral perfusion characteristics, determined by MR imaging in patients who have undergone unilateral transluminal angioplasty and stent placement.

METHODS

Eleven patients with symptomatic high-grade ICA stenosis underwent MR imaging within 4 hours before and within 3 hours after carotid stent placement. First-pass gadolinium-enhanced imaging of perfusion was performed by using a gradient-recalled echo-planar technique. Localized relative cerebral blood volume (rCBV) and bolus first-moment transit time (TT(FM)) were calculated for different vascular territories (middle, anterior, and posterior cerebral arteries) in each hemisphere.

RESULTS

Significantly longer TT(FM) (P <.005) was observed in the symptomatic territory of the middle cerebral artery before intervention. After intervention, TT(FM) remained significantly longer in this territory (P <.05). However, the magnitude of the interhemispheric asymmetry had declined significantly (50-60% reduction; P <.05). No significant differences or changes in rCBV were identified between hemispheres, between images, or in areas of unilateral leptomeningeal enhancement after intervention.

CONCLUSION

MR can demonstrate short-term partial resolution of timing asymmetry in interhemispheric perfusion after angioplasty and stent insertion for severe stenosis of the ICA.