Unilateral leptomeningeal enhancement after carotid stent insertion detected by magnetic resonance imaging

Background and Purpose-Percutaneous transluminal angioplasty combined with vascular stenting is currently being assessed in the treatment of patients with symptomatic, severe carotid stenosis. The immediate cerebral hemodynam ic effects resulting from stenting are not fully understood. This article d escribes a novel finding: abnormal leptomeningeal enhancement after stentin g shown by MRI. Methods-Fourteen patients with symptomatic severe carotid bifurcation steno sis underwent MRI within 4 hours before and within 3 hours after attempted carotid stenting. Twelve patients were successfully stented. Part of the NI R investigation consisted of the acquisition of TI-weighted images before a nd after administration of the contrast agent Gd-DTPA, both before and afte r the procedure. Results-All 12 patients who underwent successful stenting did not have abno rmal enhancement of the leptomeninges before stenting but developed unilate ral enhancement following intervention but before the second injection of c ontrast agent. No contrast enhancement was detected in the 2 patients who h ad the angiographic procedure but were not stented. Conclusions-These findings suggest that abnormal changes to the leptomening eal vasculature occur during carotid stenting which are not associated with sudden development of neurological symptoms. The anatomic distribution of the enhancement suggests that it is a consequence of the sudden change in b rain hemodynamics secondary to the improvement in carotid flow after stenti ng.