Extravasation of contrast medium into the subdural space during cavernous sinus venography: a rare complication.

We recently observed subdural extravasation of contrast medium during transfemoral catheter venography of the cavernous sinus, performed to elucidate the relationship between a parasellar mass and the sinus. The precise mechanism is unknown but a dural tear during manipulation of the guide wire or catheter was thought to be the most likely cause.