title: Hemodynamic Differences in Intracranial Aneurysms before and after Rupture.
abstract: OBJECTIVE
  Rupture risk of intracranial aneurysms may depend on hemodynamic characteristics. This has been assessed by comparing hemodynamic data of ruptured and unruptured aneurysms. However, aneurysm geometry may change before, during, or just after rupture; this difference causes potential changes in hemodynamics. We assessed changes in hemodynamics in a series of intracranial aneurysms, by using 3D imaging before and after rupture.
  
  
  METHODS
  For 9 aneurysms in 9 patients, we used MRA, CTA, and 3D rotational angiography before and after rupture to generate geometric models of the aneurysm and perianeurysmal vasculature. Intra-aneurysmal hemodynamics were simulated by using computational fluid dynamics. Two neuroradiologists qualitatively assessed flow complexity, flow stability, inflow concentration, and flow impingement in consensus, by using flow-velocity streamlines and wall shear stress distributions.
  
  
  RESULTS
  Hemodynamics changed in 6 of the 9 aneurysms. The median time between imaging before and after rupture was 678 days (range, 14-1461 days) in these 6 cases, compared with 151 days (range, 34-183 days) in the 3 cases with unaltered hemodynamics. Changes were observed for flow complexity (n = 3), flow stability (n = 3), inflow concentration (n = 2), and region of flow impingement (n = 3). These changes were in all instances associated with aneurysm displacement due to rupture-related hematomas, growth, or newly formed lobulations.
  
  
  CONCLUSIONS
  Hemodynamic characteristics of intracranial aneurysms can be altered by geometric changes before, during, or just after rupture. Associations of hemodynamic characteristics with aneurysm rupture obtained from case-control studies comparing ruptured with unruptured aneurysms should therefore be interpreted with caution.
authors.affiliation: From the MIRA Institute for Biomedical Engineering and Technical Medicine (B.M.W.C., C.H.S.), University of Twente, Enschede, the Netherlands Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.) Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands b.m.cornelissen@amc.uva.nl.
authors.forename: B M W
authors.initials: BM
authors.lastname: Cornelissen
authors.affiliation: Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.).
authors.forename: J J
authors.initials: JJ
authors.lastname: Schneiders
authors.affiliation: Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.).
authors.forename: W V
authors.initials: WV
authors.lastname: Potters
authors.affiliation: Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.).
authors.forename: R
authors.initials: R
authors.lastname: van den Berg
authors.affiliation: Departments of Radiology (B.K.V.).
authors.forename: B K
authors.initials: BK
authors.lastname: Velthuis
authors.affiliation: Neurology and Neurosurgery, Brain Center Rudolf Magnus (G.J.E.R.), University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: G J E
authors.initials: GJ
authors.lastname: Rinkel
authors.affiliation: From the MIRA Institute for Biomedical Engineering and Technical Medicine (B.M.W.C., C.H.S.), University of Twente, Enschede, the Netherlands.
authors.forename: C H
authors.initials: CH
authors.lastname: Slump
authors.affiliation: Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: VanBavel
authors.affiliation: Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.).
authors.forename: C B L M
authors.initials: CB
authors.lastname: Majoie
authors.affiliation: Departments of Radiology (B.M.W.C., J.J.S., W.V.P., R.v.d.B., C.B.L.M.M., H.A.M.) Biomedical Engineering and Physics (B.M.W.C, E.V., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
mesh_terms: D000293:Adolescent; D000328:Adult; D017542:Aneurysm, Ruptured / Q000175:diagnosis* / Q000503:physiopathology*; D002533:Cerebral Angiography / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D066230:Patient-Specific Modeling; D013314:Stress, Mechanical; D055815:Young Adult