title: Measuring Cerebral Blood Flow in Moyamoya Angiopathy by Quantitative Magnetic Resonance Angiography Noninvasive Optimal Vessel Analysis.
abstract: BACKGROUND
  Moyamoya disease causes progressive occlusion of the supraclinoidal internal carotid artery, and middle, anterior, and less frequently the posterior cerebral arteries, carrying the risk of stroke. Blood flow is often partially reconstituted by compensatory moyamoya collaterals and sometimes the posterior circulation. Cerebral revascularization can further augment blood flow. These changes to blood flow within the cerebral vessels, however, are not well characterized.
  
  
  OBJECTIVE
  To evaluate blood flow changes resulting from the disease process and revascularization surgery using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA).
  
  
  METHODS
  We retrospectively analyzed 190 preoperative and postoperative imaging scans in 66 moyamoya patients after revascularization surgery. Images were analyzed for blood flow using NOVA and compared with preoperative angiographic staging and postoperative blood flow. Blood flow rates within superficial temporal artery grafts were compared based on angiographic evidence of patency.
  
  
  RESULTS
  Diseased vessels had lower blood flow, correlating with angiographic staging. Flow in posterior cererbal and basilar arteries increased with disease severity, particularly when both the anterior and middle cerebral arteries were occluded. Basilar artery flow and ipsilateral internal carotid artery flow decreased after surgery. Flow rates were different between angiographically robust and poor direct bypass grafts, as well as between robust and patent grafts.
  
  
  CONCLUSIONS
  Preoperative changes in cerebral vessel flow as measured by NOVA correlated with angiographic disease progression. NOVA demonstrated that preoperative augmentation of the posterior circulation decreased after surgery. This report is the first to quantify the shift in collateral supply from the posterior circulation to the bypass graft.
authors.forename: Nadia
authors.initials: N
authors.lastname: Khan
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lober
authors.forename: Lauren
authors.initials: L
authors.lastname: Ostergren
authors.forename: Jacob
authors.initials: J
authors.lastname: Petralia
authors.affiliation: Department of Neurosurgery, Stanford Stroke Center, Stanford University School of Medicine, Stanford, California.
authors.forename: Teresa
authors.initials: T
authors.lastname: Bell-Stephens
authors.affiliation: Department of Neurosurgery, Stanford Stroke Center, Stanford University School of Medicine, Stanford, California.
authors.forename: Ramon
authors.initials: R
authors.lastname: Navarro
authors.affiliation: Department of Neurosurgery, Stanford Stroke Center, Stanford University School of Medicine, Stanford, California.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Feroze
authors.affiliation: Department of Neurosurgery, Stanford Stroke Center, Stanford University School of Medicine, Stanford, California.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Steinberg
mesh_terms: D000328:Adult; D002548:Cerebral Revascularization / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009072:Moyamoya Disease / Q000000981:diagnostic imaging* / Q000601:surgery; D012189:Retrospective Studies
keywords: Cerebral blood flow; Moyamoya disease; Noninvasive optimal vessel analysis (NOVA); Quantitative MRI (QMRI)