title: Numerical modeling of the flow in intracranial aneurysms: prediction of regions prone to thrombus formation.
abstract: The deposition of intralumenal thrombus in intracranial aneurysms adds a risk of thrombo-embolism over and above that posed by mass effect and rupture. In addition to biochemical factors, hemodynamic factors that are governed by lumenal geometry and blood flow rates likely play an important role in the thrombus formation and deposition process. In this study, patient-specific computational fluid dynamics (CFD) models of blood flow were constructed from MRA data for three patients who had fusiform basilar aneurysms that were thrombus free and then proceeded to develop intralumenal thrombus. In order to determine whether features of the flow fields could suggest which regions had an elevated potential for thrombus deposition, the flow was modeled in the baseline, thrombus-free geometries. Pulsatile flow simulations were carried out using patient-specific inlet flow conditions measured with MR velocimetry. Newtonian and non-Newtonian blood behavior was considered. A strong similarity was found between the intra-aneurysmal regions with CFD-predicted slow, recirculating flows and the regions of thrombus deposition observed in vivo in the follow-up MR studies. In two cases with larger aneurysms, the agreement between the low velocity zones and clotted-off regions improved when non-Newtonian blood behavior was taken into account. A similarity was also found between the calculated low shear stress regions and the regions that were later observed to clot.
authors.affiliation: Radiology Service, VA Medical Center-San Francisco, 4150 Clement Street, San Francisco, CA 94121, USA. vlrayz@gmail.com
authors.forename: V L
authors.initials: VL
authors.lastname: Rayz
authors.forename: L
authors.initials: L
authors.lastname: Boussel
authors.forename: M T
authors.initials: MT
authors.lastname: Lawton
authors.forename: G
authors.initials: G
authors.lastname: Acevedo-Bolton
authors.forename: L
authors.initials: L
authors.lastname: Ge
authors.forename: W L
authors.initials: WL
authors.lastname: Young
authors.forename: R T
authors.initials: RT
authors.lastname: Higashida
authors.forename: D
authors.initials: D
authors.lastname: Saloner
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000503:physiopathology*; D008955:Models, Cardiovascular; D013927:Thrombosis / Q000503:physiopathology*
references.citation: IEEE Trans Med Imaging. 2005 Apr;24(4):457-67
references.pmid: 15822804
references.citation: J Neurosurg. 2001 Dec;95(6):1020-7
references.pmid: 11765817
references.citation: J Biomech Eng. 2008 Apr;130(2):021004
references.pmid: 18412491
references.citation: AJNR Am J Neuroradiol. 2001 Apr;22(4):721-4
references.pmid: 11290486
references.citation: AJNR Am J Neuroradiol. 2006 May;27(5):1113-8
references.pmid: 16687554
references.citation: AJNR Am J Neuroradiol. 2004 Jan;25(1):63-8
references.pmid: 14729530
references.citation: Heart Vessels. 1987;3(2):55-65
references.pmid: 3500943
references.citation: Neurosurgery. 1995 Oct;37(4):774-82; discussion 782-4
references.pmid: 8559308
references.citation: AJNR Am J Neuroradiol. 2003 Apr;24(4):559-66
references.pmid: 12695182
references.citation: Magn Reson Med. 2000 Apr;43(4):565-76
references.pmid: 10748432
references.citation: Crit Rev Biomed Eng. 1998;26(4):227-74
references.pmid: 10065891
references.citation: Biorheology. 1985;22(6):521-31
references.pmid: 3834958
references.citation: J Biomech. 1996 Jul;29(7):899-908
references.pmid: 8809620
references.citation: J Biomech. 2000 Aug;33(8):975-84
references.pmid: 10828328
references.citation: Acta Neurochir (Wien). 1987;86(3-4):98-105
references.pmid: 3630787
references.citation: AJNR Am J Neuroradiol. 2007 Apr;28(4):622-7
references.pmid: 17416810
references.citation: Comput Aided Surg. 1999;4(5):231-47
references.pmid: 10581521
references.citation: AJNR Am J Neuroradiol. 2005 Oct;26(9):2357-63
references.pmid: 16219845
references.citation: Biorheology. 1993 May-Aug;30(3-4):287-98
references.pmid: 8286729
references.citation: J Biomech Eng. 2002 Feb;124(1):9-20
references.pmid: 11871610
references.citation: J Biomech Eng. 2008 Oct;130(5):051011
references.pmid: 19045518
references.citation: J Magn Reson Imaging. 2000 Mar;11(3):299-311
references.pmid: 10739562
references.citation: Biorheology. 2005;42(6):493-509
references.pmid: 16369086
references.citation: J Biomech Eng. 2006 Aug;128(4):516-26
references.pmid: 16813443
references.citation: AJNR Am J Neuroradiol. 2006 Sep;27(8):1703-9
references.pmid: 16971618
references.citation: IEEE Eng Med Biol Mag. 1999 Nov-Dec;18(6):33-9
references.pmid: 10576070
references.citation: AJNR Am J Neuroradiol. 1996 Sep;17(8):1417-21
references.pmid: 8883635
references.citation: J Biomech. 2006;39(6):1116-28
references.pmid: 16549100
references.citation: Ann Biomed Eng. 2002 Apr;30(4):483-97
references.pmid: 12086000
references.citation: Monogr Atheroscler. 1990;15:63-76
references.pmid: 2404201
references.citation: Biorheology. 1989;26(6):1011-30
references.pmid: 2624892
references.citation: Ann Biomed Eng. 2002 Apr;30(4):509-23
references.pmid: 12086002