title: Intracranial 4D flow MRI: toward individualized assessment of arteriovenous malformation hemodynamics and treatment-induced changes.
abstract: OBJECTIVE
  Arteriovenous malformations are an important etiology of hemorrhagic stroke. However, current imaging modalities and risk do not provide insights into individual AVM hemodynamics and its role in pathophysiology. The aims of this study are to determine whether intracranial 4D flow MR imaging can provide insights into arteriovenous malformation hemodynamics independent of the Spetzler-Martin grade and to report the changes in flow observed during staged embolization.
  
  
  METHODS
  Intracranial 3D blood flow was assessed in 20 patients with AVM (age = 39 ± 15 years, Spetzler-Martin grade ranging from 1-4) with the use of 4D flow MR imaging (temporal resolution = 45 ms, spatial resolution = [1.2-1.6mm](3)). AVM hemodynamics were visualized by means of time-integrated 3D pathlines depicting the AVM arterial feeding and venous draining patterns over the cardiac cycle. Analysis included the grading of feeding and draining velocities on a 3-point scale (0 = low <25 cm/s, 1 = medium <50 cm/s, 2 = high >50 cm/s). For 4 of 20 patients undergoing 4D flow MR imaging follow-up after staged embolization, peak velocities were quantified in arterial feeders, draining veins, the sagittal sinus, and contralateral arteries.
  
  
  RESULTS
  In 50% of the cases with Spetzler-Martin grade >2, heterogeneous flow (velocity grade differences >1) was found across arteries and veins. Velocities in draining veins increased from Spetzler-Martin grade = 1 (grading = 0.5 ± 0.6) to Spetzler-Martin grade ≥3 (1.1 ± 0.6), whereas arterial velocities were similar (1.7 ± 0.6 versus 1.5 ± 0.6). In the postembolization subgroup of 4 patients, 4D flow MR imaging demonstrated successively more compact AVM and redistribution of velocities. Changes in arterial and venous velocities during treatment were highly different among individuals.
  
  
  CONCLUSIONS
  Spetzler-Martin grade does not reflect differences in 3D AVM arterial and venous hemodynamics, and an individual assessment of AVM hemodynamics may be needed for improved lesion characterization. Four-dimensional flow MR imaging may have the potential to monitor and guide embolization treatment planning.
authors: Department of Radiology.
authors: S A
authors: SA
authors: Ansari
authors: S
authors: S
authors: Schnell
authors: T
authors: T
authors: Carroll
authors: P
authors: P
authors: Vakil
authors: M C
authors: MC
authors: Hurley
authors: C
authors: C
authors: Wu
authors: J
authors: J
authors: Carr
authors: B R
authors: BR
authors: Bendok
authors: H
authors: H
authors: Batjer
authors: M
authors: M
authors: Markl
mesh_terms: D000328:Adult; D002536:Cerebral Arteries / Q000473:pathology; D002550:Cerebral Veins / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D055815:Young Adult
references: J Neurol. 2005 Sep;252(9):1021-5
references: 15742111
references: AJNR Am J Neuroradiol. 2007 Mar;28(3):433-8
references: 17353308
references: Stroke. 2001 Jun;32(6):1458-71
references: 11387517
references: Eur J Cardiothorac Surg. 2011 Feb;39(2):206-12
references: 20598560
references: Eur Radiol. 1998;8(5):685-90
references: 9601953
references: Neurol Res. 2012 Jul;34(6):552-6
references: 22663933
references: J Neurosurg. 1986 Oct;65(4):476-83
references: 3760956
references: AJNR Am J Neuroradiol. 2013 Jan;34(1):46-53
references: 22878012
references: Stroke. 2005 Nov;36(11):2431-5
references: 16224095
references: Magn Reson Med. 2010 Feb;63(2):330-8
references: 20024953
references: Stroke. 2009 Jan;40(1):100-5
references: 19008469
references: J Magn Reson Imaging. 2007 Apr;25(4):824-31
references: 17345635
references: AJNR Am J Neuroradiol. 2012 Sep;33(8):1565-72
references: 22499844
references: Neurosurg Clin N Am. 2012 Jan;23(1):133-46
references: 22107864
references: Stroke. 2010 Jun;41(6):1145-50
references: 20431080
references: AJNR Am J Neuroradiol. 2009 Feb;30(2):362-6
references: 18653687
references: J Magn Reson Imaging. 2012 Aug;36(2):443-53
references: 22535682
references: Neurology. 2006 May 9;66(9):1350-5
references: 16682666
references: AJNR Am J Neuroradiol. 2003 Apr;24(4):567-78
references: 12695183
references: Magn Reson Med. 2007 Jan;57(1):127-40
references: 17195166
references: N Engl J Med. 1999 Jun 10;340(23):1812-8
references: 10362826
references: Neuroradiology. 2010 Oct;52(10):921-8
references: 20012431
references: Ann Biomed Eng. 2010 Oct;38(10):3058-69
references: 20499185
references: Neurosurgery. 2008 May;62(5 Suppl):A44-52; discussion A52
references: 18580780
references: N Engl J Med. 1988 Aug 11;319(6):343-7
references: 3393196
references: Eur J Radiol. 2006 Dec;60(3):367-78
references: 16965882
references: Neurosurgery. 1987 Sep;21(3):314-23
references: 3670575
references: Radiology. 2008 Jan;246(1):205-13
references: 17951352
references: Magn Reson Imaging. 2010 Jan;28(1):41-6
references: 19577400
references: Eur J Radiol. 2011 Dec;80(3):776-9
references: 20950972
references: AJNR Am J Neuroradiol. 2010 Jan;31(1):80-5
references: 19833802
references: Circulation. 2001 May 29;103(21):2644-57
references: 11382737
references: Neurosurgery. 1988 Sep;23(3):322-8
references: 3265763
references: Stroke. 2009 Aug;40(8):2749-53
references: 19478223
references: Neuroradiology. 2008 Jun;50(6):473-84
references: 18350286