Extravasating contrast material on angiography following carotid angioplasty and stenting: not necessarily subarachnoid hemorrhage.

We describe a case of asymptomatic extravasation of iodinated contrast material into the sulci on digital subtraction angiography following carotid angioplasty and stenting resulting in sulcal hyperdensity on computed tomography (CT). We believe the mechanism for this observation is hyperperfusion injury and that in the absence of any associated clinical signs, it should not be considered alarming for subarachnoid hemorrhage.