title: Nonenhanced ECG-gated time-resolved 4D steady-state free precession (SSFP) MR angiography (MRA) of cerebral arteries: comparison at 1.5T and 3T.
abstract: OBJECTIVE
  To compare image quality of nonenhanced time-resolved 4D steady-state free precession MR angiography (4D SSFP MRA) of cerebral arteries at 1.5T and 3T.
  
  
  METHODS
  12 healthy subjects (mean age 29.4±6.9 years) were studied at both 1.5T and 3T. Two different positions of the acquisition slab were evaluated; in one acquisition the imaging slab included the carotid siphon ("S(low)"), in the other acquisition the imaging slab was placed superior to the carotid siphon ("S(high)"). Subjective image quality of cerebral arteries was assessed independently by two readers on a 4-point scale. Relative Signal-to-Noise-Ratio (SNR) was determined for the M1 segment of the middle cerebral artery.
  
  
  RESULTS
  Subjective image quality of the anterior cerebral artery (segments A1, A2) was significantly higher at 1.5T as compared to 3T, while 3T provided significantly higher image quality for segment P3 of the posterior cerebral artery. For the middle cerebral artery (segments M1-M3), image quality was significantly higher at 1.5T than at 3T when the carotid siphon was included in the acquisition slab ("S(low)"), while no significant difference was found between 1.5T and 3T with "S(high)". Relative SNR was significantly higher at 1.5T (23.1±5.1) as compared to 3T (12.1±7.8) for "S(low)" and significantly higher at 3T (29.8±5.9) than at 1.5T (24.2±3.6) for "S(high)".
  
  
  CONCLUSIONS
  Our results indicate that 4D SSFP MRA should preferably be performed at 1.5T with inclusion of the carotid siphon in the acquisition slab, which might be required for the assessment of intracranial collateral flow.
authors: Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, Moorenstr. 5, 40225 Düsseldorf, Germany. Rotem.Lanzman@med.uni-duesseldorf.de
authors: R S
authors: RS
authors: Lanzman
authors: P
authors: P
authors: Kröpil
authors: P
authors: P
authors: Schmitt
authors: H J
authors: HJ
authors: Wittsack
authors: D
authors: D
authors: Orzechowski
authors: J
authors: J
authors: Kuhlemann
authors: C
authors: C
authors: Buchbender
authors: F R
authors: FR
authors: Miese
authors: G
authors: G
authors: Antoch
authors: D
authors: D
authors: Blondin
mesh_terms: D000328:Adult; D000465:Algorithms; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D002533:Cerebral Angiography / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media