Angiographic features of subdural empyema.

Subdural empyema, a relatively rare intracranial suppurative disease, is a surgical emergency and requires early diagnosis in order to ensure patient survival. Subdural empyema should be considered with one or a combination of the following in conjunction with an extracerebral collection: (a) an irregular border of the extracerebral collection; (b) a thickened vascular wall of dura; (c) a semilunar avascular zone on the lateral view; (d) spasm of the large arteries at the base of the brain with or without segmental arterial dilatation; (e) multiple peripheral arterial occlusions; and (f) enlargement of the anterior falx artery. Four verified cases are presented.