title: In vivo hemodynamic analysis of intracranial aneurysms obtained by magnetic resonance fluid dynamics (MRFD) based on time-resolved three-dimensional phase-contrast MRI.
abstract: BACKGROUND
  Hemodynamics is thought to play a very important role in the initiation, growth, and rupture of intracranial aneurysms. The purpose of our study was to perform in vivo hemodynamic analysis of unruptured intracranial aneurysms of magnetic resonance fluid dynamics using time-resolved three-dimensional phase-contrast MRI (4D-Flow) at 1.5 T and to analyze relationships between hemodynamics and wall shear stress (WSS) and oscillatory shear index (OSI).
  
  
  METHODS
  This study included nine subjects with 14 unruptured aneurysms. 4D-Flow was performed by a 1.5-T magnetic resonance scanner with a head coil. We calculated in vivo streamlines, WSS, and OSI of intracranial aneurysms based on 4D-Flow with our software. We evaluated the number of spiral flows in the aneurysms and compared the differences in WSS or OSI between the vessel and aneurysm and between whole aneurysm and the apex of the spiral flow.
  
  
  RESULTS
  3D streamlines, WSS, and OSI distribution maps in arbitrary direction during the cardiac phase were obtained for all intracranial aneurysms. Twelve aneurysms had one spiral flow each, and two aneurysms had two spiral flows each. The WSS was lower and the OSI was higher in the aneurysm compared to the vessel. The apex of the spiral flow had a lower WSS and higher OSI relative to the whole aneurysm.
  
  
  CONCLUSIONS
  Each intracranial aneurysm in this study had at least one spiral flow. The WSS was lower and OSI was higher at the apex of the spiral flow than the whole aneurysmal wall.
authors.affiliation: Department of Radiology, Hamamatsu University School of Medicine, 1-20-1 Handayama Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan. hisoda@hama-med.ac.jp
authors.forename: Haruo
authors.initials: H
authors.lastname: Isoda
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Ohkura
authors.forename: Takashi
authors.initials: T
authors.lastname: Kosugi
authors.forename: Masaya
authors.initials: M
authors.lastname: Hirano
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Takeda
authors.forename: Hisaya
authors.initials: H
authors.lastname: Hiramatsu
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamashita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takehara
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Alley
authors.forename: Roland
authors.initials: R
authors.lastname: Bammer
authors.forename: Norbert J
authors.initials: NJ
authors.lastname: Pelc
authors.forename: Hiroki
authors.initials: H
authors.lastname: Namba
authors.forename: Harumi
authors.initials: H
authors.lastname: Sakahara
mesh_terms: 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* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity