title: Dynamic contrast-enhanced MRA at 1.5 T for detection of arteriovenous shunting before and after Onyx embolization of cerebral arteriovenous malformations.
abstract: BACKGROUND
  Conventional non-invasive angiographic techniques for evaluating cerebral Arteriovenous Malformations (cAVMs) after embolization treatment are limited by their inability to acquire time-resolved images. We describe the use of dynamic contrast-enhanced magnetic resonance angiography (MRA) in the evaluation of residual arteriovenous shunting in cAVMs following Onyx embolization.
  
  
  METHODS
  Six subjects who underwent multimodal MR imaging including dynamic MRA after different stages of endovascular treatment with Onyx were included. Each MRA was assessed for the presence of residual arteriovenous shunting. The results were compared with digital subtraction angiography (DSA).
  
  
  RESULTS
  Mean age was 41 years (range, 25-63) and the mean maximum AVM diameter was 5.3 cm (range, 4.7-6.0). Fourteen dynamic MRA were performed using a 1.5 T scanner. Arteriovenous shunting was detected in thirteen of fourteen patients by both dynamic MRA and DSA, with complete agreement between the two techniques. The only MRA without detectable residual arteriovenous shunting was for a subject who had complete treatment with no residual cAVM as confirmed by the DSA images.
  
  
  CONCLUSIONS
  Dynamic contrast-enhanced MRA is a promising non-invasive modality in identifying residual arteriovenous shunting after different stages of AVM embolization, achieving 100% agreement in this small study. Embolization with Onyx caused no significant image artifact.
authors: Departments of Neurology; Departments of Neurology, Neurosurgery, and Radiology, Emory University School of Medicine, Marcus Stroke & Neuroscience Center, Grady Memorial Hospital, Atlanta, GA.
authors: Raul G
authors: RG
authors: Nogueira
authors: Ahmad
authors: A
authors: Bayrlee
authors: Joshua A
authors: JA
authors: Hirsch
authors: Albert J
authors: AJ
authors: Yoo
authors: William A
authors: WA
authors: Copen
mesh_terms: D000328:Adult; D003287:Contrast Media; D004121:Dimethyl Sulfoxide / Q000627:therapeutic use*; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006490:Hemostatics / Q000627:therapeutic use; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology* / Q000628:therapy*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011145:Polyvinyls / Q000627:therapeutic use*; D017211:Treatment Failure; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D006490:Hemostatics; C450660:Onyx copolymer; D011145:Polyvinyls; D019786:Gadolinium DTPA; D004121:Dimethyl Sulfoxide
keywords: Cerebral arteriovenous malformation; MRI; Onyx; TRICKS