title: Identification of the inflow zone of unruptured cerebral aneurysms: comparison of 4D flow MRI and 3D TOF MRA data.
abstract: OBJECTIVE
  The hemodynamics of the inflow zone of cerebral aneurysms may be a key factor in coil compaction and recanalization after endovascular coil embolization. We performed 4D flow MR imaging in conjunction with 3D TOF MRA and compared their ability to identify the inflow zone of unruptured cerebral aneurysms.
  
  
  METHODS
  This series comprised 50 unruptured saccular cerebral aneurysms in 44 patients. Transluminal color-coded 3D MRA images were created by selecting the signal-intensity ranges on 3D TOF MRA images that corresponded with both the luminal margin and the putative inflow.
  
  
  RESULTS
  4D flow MR imaging demonstrated the inflow zone and yielded inflow velocity profiles for all 50 aneurysms. In 18 of 24 lateral-projection aneurysms (75%), the inflow zone was located distally on the aneurysmal neck. The maximum inflow velocity ranged from 285 to 922 mm/s. On 4D flow MR imaging and transluminal color-coded 3D MRA studies, the inflow zone of 32 aneurysms (64%) was at a similar location. In 91% of aneurysms whose neck section plane angle was <30° with respect to the imaging section direction on 3D TOF MRA, depiction of the inflow zone was similar on transluminal color-coded 3D MRA and 4D flow MR images.
  
  
  CONCLUSIONS
  4D flow MR imaging can demonstrate the inflow zone and provide inflow velocity profiles. In aneurysms whose angle of the neck-section plane is obtuse vis-a-vis the imaging section on 3D TOF MRA scans, transluminal color-coded 3D MRA may depict the inflow zone reliably.
authors.affiliation: From the Department of Neurosurgery (K.F.), Mattoh-Ishikawa Central Hospital, Ishikawa, Japan kfutami@mattohp.com.
authors.forename: K
authors.initials: K
authors.lastname: Futami
authors.affiliation: Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Sano
authors.affiliation: Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Misaki
authors.affiliation: Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakada
authors.affiliation: From the Department of Neurosurgery (K.F.), Mattoh-Ishikawa Central Hospital, Ishikawa, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Ueda
authors.affiliation: Departments of Neurosurgery (H.S., K.M., M.N., J.H.) and Radiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Hamada
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D017542:Aneurysm, Ruptured / Q000473:pathology / Q000503:physiopathology; D001783:Blood Flow Velocity; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002532:Intracranial Aneurysm / Q000473:pathology* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity