title: 3D cine phase-contrast MRI at 3T in intracranial aneurysms compared with patient-specific computational fluid dynamics.
abstract: OBJECTIVE
  CFD has been proved valuable for simulating blood flow in intracranial aneurysms, which may add to better rupture risk assessment. However, CFD has drawbacks such as the sensitivity to assumptions needed for the model, which may hinder its clinical implementation. 3D PC-MR imaging is a technique that enables measurements of blood flow. The purpose of this study was to compare flow patterns on the basis of 3D PC-MR imaging with CFD estimates.
  
  
  METHODS
  3D PC-MR imaging was performed in 8 intracranial aneurysms. Two sets of patient-specific inflow boundaries for CFD were obtained from a separate 2D PC-MR imaging sequence (2D CFD) and from the 3D PC-MR imaging (3D CFD) data. 3D PC-MR imaging and CFD were compared by calculation of the differences between velocity vector magnitudes and angles. Differences in flow patterns expressed as the presence and strengths of vortices were determined by calculation of singular flow energy.
  
  
  RESULTS
  In systole, flow features such as vortex patterns were similar. In diastole, 3D PC-MR imaging measurements appeared inconsistent due to low velocity-to-noise ratios. The relative difference in velocity magnitude was 67.6 ± 51.4% and 27.1 ± 24.9% in systole and 33.7 ± 21.5% and 17.7 ± 10.2% in diastole for 2D CFD and 3D CFD, respectively. For singular energy, this was reduced to 15.5 ± 13.9% at systole and 19.4 ± 17.6% at diastole (2D CFD).
  
  
  CONCLUSIONS
  In systole, good agreement between 3D PC-MR imaging and CFD on flow-pattern visualization and singular-energy calculation was found. In diastole, flow patterns of 3D PC-MR imaging differed from those obtained from CFD due to low velocity-to-noise ratios.
authors.affiliation: Departments of Radiology.
authors.forename: P
authors.initials: P
authors.lastname: van Ooij
authors.forename: J J
authors.initials: JJ
authors.lastname: Schneiders
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
authors.forename: C B
authors.initials: CB
authors.lastname: Majoie
authors.forename: E
authors.initials: E
authors.lastname: van Bavel
authors.forename: A J
authors.initials: AJ
authors.lastname: Nederveen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D008959:Models, Neurological; D018802:Patient-Centered Care; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods; D012680:Sensitivity and Specificity; D055815:Young Adult