title: Complete regression of intracranial arteriovenous malformations.
abstract: BACKGROUND
  Spontaneous and complete regression of intracranial arteriovenous malformations (AVMs) is a rare occurrence, with only 59 angiographically proven cases reported in the English literature. We present three new cases and perform a literature review to determine possible mechanisms underlying this unusual phenomenon.
  
  
  METHODS
  Three patients with angiographically proven AVMs demonstrated complete obliteration of the AVM on follow-up angiography. Two patients had MRIs performed at the time of follow-up angiography.
  
  
  RESULTS
  A literature review of all reported cases shows that the vast majority (88%) of spontaneously closing AVMs had a single draining vein as did our three cases. In addition, hemodynamic alterations of intracranial (IC) blood flow, including intracranial hemorrhage, were seen in a majority (79%) of patients, including two of our three cases. MRI was performed in two of our three cases and showed a thrombosed-draining vein in both.
  
  
  CONCLUSIONS
  Complete spontaneous regression of intracranial AVMs is a rare occurrence. The phenomenon seems to require the interaction of hemodynamic changes in compromising or closing the limited, usually single, venous drainage pathway from the AVM. Hemorrhage may contribute to the effect by further compromising flow though the lesion, or it may merely be a phenomenon associated with the effects of venous hypertension on the AVM nidus.
authors.affiliation: Department of Neuroradiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Schwartz
authors.forename: Robert W
authors.initials: RW
authors.lastname: Hurst
authors.forename: Grant
authors.initials: G
authors.lastname: Sinson
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Bagley
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D012075:Remission, Spontaneous