Angiographic demonstration of acute phase of intracranial arterial spasm following aneurysm rupture. Case report. A case documenting the acute phase of intracranial arterial spasm following rupture of an aneurysm arising from the left internal carotid artery is reported. The patient deteriorated due to recurrent hemorrhage while undergoing angiography 12 hours after the initial aneurysm rupture. The acute deterioration was accompanied by dilatation of the ipsilateral pupil and occurred during injection of contrast material. There was delayed filling of the middle cerebral artery complex along with this narrowing. The arterial narrowing was confirmed to have completely disappeared on an angiographic series performed 14 minutes after the first series of films. The etiology of the acute vasospasm is discussed. 