title: Measurement of blood flow in arteriovenous malformations before and after embolization using arterial spin labeling.
abstract: The assessment of shunt reduction after an embolization of an arteriovenous malformation (AVM) or fistula (AVF) from conventional angiography is often difficult and may be subjective.  Here we present a completely non-invasive method using magnetic resonance imaging (MRI) to measure shunt reduction. Using pulsed arterial spin labeling (PASL), we determined the relative amount of signal attributed to the shunt over 1.75 s and 6 different slices covering the lesion. This amount of signal from the shunt was related to the total signal from all slices and measured before and after embolization. The method showed a fair agreement between the PASL results and the judgement from conventional angiography. In the case of a total or subtotal shunt occlusion, PASL showed a shunt reduction between 69% and 92%, whereas in minimal shunt reduction as judged by conventional angiography, the ASL result was -6% (indicating slightly increased flow) to 35% in a partially occluded vein of Galen aneurysm. The PASL method proved to be fairly reproducible (up to 2% deviation between three measurements without interventions). On conclusion, PASL is able to reliably measure the amount of shunt reduction achieved by embolization of AVMs and AVFs.
authors.affiliation: CEDIMAT, Plaza de la Salud, Santo Domingo, Republica Dominicana.
authors.forename: L
authors.initials: L
authors.lastname: Suazo
authors.forename: B
authors.initials: B
authors.lastname: Foerster
authors.forename: R
authors.initials: R
authors.lastname: Fermin
authors.forename: H
authors.initials: H
authors.lastname: Speckter
authors.forename: C
authors.initials: C
authors.lastname: Vilchez
authors.forename: J
authors.initials: J
authors.lastname: Oviedo
authors.forename: P
authors.initials: P
authors.lastname: Stoeter
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004621:Embolization, Therapeutic; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000592:standards; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D013113:Spin Labels; D016896:Treatment Outcome
chemical_list: D013113:Spin Labels