title: Dynamic Magnetic Resonance Angiography Provides Collateral Circulation and Hemodynamic Information in Acute Ischemic Stroke.
abstract: OBJECTIVE
  Contrary to usual static vascular imaging techniques, contrast-enhanced dynamic magnetic resonance angiography (dMRA) enables dynamic study of cerebral vessels. We evaluated dMRA ability to assess arterial occlusion, cerebral hemodynamics, and collateral circulation in acute ischemic stroke.
  
  
  METHODS
  Twenty-five acute ischemic stroke patients with proximal anterior circulation occlusion underwent dMRA on a 3T scanner within 12 hours of symptoms onset. Diffusion weighted imaging, Tmax6 s lesion volumes and hypoperfusion intensity ratio as volume of Tmax>6 s/volume of Tmax>10 s were measured. Site and grade of occlusion (Thrombolysis in Myocardial Infarction criteria) were evaluated on time-of-flight MRA and dMRA. Leptomeningeal collaterality (American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology [ASITN/SIR] Scale) and asymmetries in venous clearance were assessed exclusively on dMRA. Collateral filling was dichotomized into incomplete (ASITN/SIR 0-2) or complete (ASITN/SIR 3-4).
  
  
  RESULTS
  On dMRA, site of occlusion was M1 in 21 patients, tandem internal carotid artery/M1 in 2 and tandem internal carotid artery/terminal internal carotid artery in 2 patients. Three tandem occlusions were not detected on time-of-flight-MRA. All patients had Thrombolysis in Myocardial Infarction 0 to 1 on time-of-flight-MRA, but three of them had Thrombolysis in Myocardial Infarction 2 on dMRA. Complete collateral filling (n=12, 48%) was associated with smaller diffusion weighted imaging lesion volume (P=0.039), smaller hypoperfused volume (P=0.018), and lower hypoperfusion intensity ratio (P=0.006). Patients with symmetrical clearance of transverse sinuses (52%) were more likely to have complete collateral filling (P=0.015).
  
  
  CONCLUSIONS
  As a fast, direct, feasible, noninvasive, and reliable method to assess site of occlusion, collateral circulation and hemodynamic alterations, dMRA provides profound insights in acute stroke.
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.). mhernandez@igtp.cat.
authors.forename: María
authors.initials: M
authors.lastname: Hernández-Pérez
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Josep
authors.initials: J
authors.lastname: Puig
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Gerard
authors.initials: G
authors.lastname: Blasco
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Natalia
authors.initials: N
authors.lastname: Pérez de la Ossa
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Laura
authors.initials: L
authors.lastname: Dorado
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Antoni
authors.initials: A
authors.lastname: Dávalos
authors.affiliation: From the Stroke Unit (M.H.-P., N.P.O., L.D., A.D.) and Diagnostic Imaging Institute (J.M.), Germans Trias i Pujol University Hospital, UAB, Badalona, Spain; and Department of Radiology, IDIBGI Diagnostic Imaging Institute, Dr Josep Trueta University Hospital, Girona, Spain (J.P., G.B.).
authors.forename: Josep
authors.initials: J
authors.lastname: Munuera
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000175:diagnosis; D002340:Carotid Artery Diseases / Q000175:diagnosis*; D002343:Carotid Artery, Internal / Q000473:pathology*; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation; D015331:Cohort Studies; D003097:Collateral Circulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D005260:Female; D006439:Hemodynamics; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000175:diagnosis
keywords: angiography; collateral circulation; stroke