title: Image analysis in time-resolved large field of view 3D MR-angiography at 3T.
abstract: OBJECTIVE
  To qualitatively and quantitatively evaluate the image quality in accelerated time-resolved 3D contrast-enhanced MR angiography (tr-CE-MRA) at 3T.
  
  
  METHODS
  In all, 113 MRA were performed in 107 patients on a 3T MR system after written informed consent and approval by the ethics committee. Twenty consecutive thoracic (n=87) or craniocervical (n=26) 3D data volumes were acquired. The timeframes with maximum arterial and venous contrast were determined and a total of 663 arterial and venous segments were analyzed by two blinded observers. Diagnostic image quality was graded by applying a 0 (low) to 3 (excellent) scale. Additionally, local signal-to-noise (SNR) and contrast-to-noise ratios (relative CNR) were evaluated.
  
  
  RESULTS
  Tr-CE-MRA was successfully performed in all patients. Good to excellent image quality (2.42+/-0.31) was observed in all individuals with preserved discrimination of arteries (2.43+/-0.48) and veins (2.20+/-0.56). Minor image degradation due to artifacts (2.62+/-0.25) and constantly high vascular signal and contrast were detected. There was a significant superiority of coronal orientation during thoracic MRA (P<0.05). In 18 cases tr-CE-MRA provided additional information on vascular pathologies.
  
  
  CONCLUSIONS
  Large field of view tr-CE-MRA enables constantly high-quality thoracic and craniocervical angiographies. In addition, the dynamics of tr-CE-MRA can offer additional information on vascular pathologies.
authors.affiliation: Department of Diagnostic Radiology and Medical Physics, University Hospital Freiburg, Germany. alex.frydrychowicz@uniklinik-freiburg.de
authors.forename: Alex
authors.initials: A
authors.lastname: Frydrychowicz
authors.forename: Thorsten A
authors.initials: TA
authors.lastname: Bley
authors.forename: Zahra Abdullah
authors.initials: ZA
authors.lastname: Zadeh
authors.forename: Andreas
authors.initials: A
authors.lastname: Harloff
authors.forename: Jan T
authors.initials: JT
authors.lastname: Winterer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hennig
authors.forename: Mathias
authors.initials: M
authors.lastname: Langer
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013895:Thoracic Arteries / Q000473:pathology*; D055815:Young Adult