title: Improved time-of-flight magnetic resonance angiography with IDEAL water-fat separation.
abstract: OBJECTIVE
  To implement IDEAL (iterative decomposition of water and fat using echo asymmetry and least squares estimation) water-fat separation with 3D time-of-flight (TOF) magnetic resonance angiography (MRA) of intracranial vessels for improved background suppression by providing uniform and robust separation of fat signal that appears bright on conventional TOF-MRA.
  
  
  METHODS
  IDEAL TOF-MRA and conventional TOF-MRA were performed in volunteers and patients undergoing routine brain MRI/MRA on a 3T magnet. Images were reviewed by two radiologists and graded based on vessel visibility and image quality.
  
  
  RESULTS
  IDEAL TOF-MRA demonstrated statistically significant improvement in vessel visibility when compared to conventional TOF-MRA in both volunteer and clinical patients using an image quality grading system. Overall image quality was 3.87 (out of 4) for IDEAL versus 3.55 for conventional TOF imaging (P = 0.02). Visualization of the ophthalmic artery was 3.53 for IDEAL versus 1.97 for conventional TOF imaging (P < 0.00005) and visualization of the superficial temporal artery was 3.92 for IDEAL imaging versus 1.97 for conventional TOF imaging (P < 0.00005).
  
  
  CONCLUSIONS
  By providing uniform suppression of fat, IDEAL TOF-MRA provides improved background suppression with improved image quality when compared to conventional TOF-MRA methods.
authors.affiliation: University of Wisconsin, Department of Radiology, Madison, Wisconsin, USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Grayev
authors.forename: Ann
authors.initials: A
authors.lastname: Shimakawa
authors.forename: Joseph
authors.initials: J
authors.lastname: Cousins
authors.forename: Patrick
authors.initials: P
authors.lastname: Turski
authors.forename: Jean
authors.initials: J
authors.lastname: Brittain
authors.forename: Scott
authors.initials: S
authors.lastname: Reeder
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography / Q000379:methods*; D002536:Cerebral Arteries / Q000033:anatomy & histology*; D002561:Cerebrovascular Disorders / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged