title: Comparison of intracranial 3D-ToF-MRA with and without parallel acquisition techniques at 1.5T and 3.0T: preliminary results.
abstract: OBJECTIVE
  To evaluate the performance of four 3D-ToF magnetic resonance angiography (MRA) sequences with and without integrated parallel acquisition techniques (iPAT) at 1.5T and 3.0T in imaging intracranial vessels.
  
  
  METHODS
  Seven volunteers and 5 patients (4 aneurysms, 1 AVM) underwent 3D-ToF-MRA at 1.5T (Magnetom Sonata) and 3.0T (Magnetom Trio) with and without parallel acquisition techniques (iPAT) using similarly designed 8-channel phased-array head coils. Imaging time of the pulse sequences was set to 7.15 and 7.35 min, respectively. Images were analyzed quantitatively by calculating signal-to-noise (SNR) and contrast-to-noise (CNR) ratios of proximal M2 segments and qualitatively by using a 5-point scale.
  
  
  RESULTS
  SNR and CNR were significantly higher for both 3D-ToF sequences at 3.0T compared with both pulse sequences at 1.5T. The highest SNR and CNR were obtained at 3.0T without iPAT. However, because of a higher spatial resolution (matrix 512 x 640) visualization of small vessel details was best at 3.0T with iPAT.
  
  
  CONCLUSIONS
  Intracranial 3D-ToF-MRA at 3.0T offers superior image quality compared with 1.5T, particular in the delineation of smaller vessels. In contrast to 1.5T, implementation of iPAT at 3.0T is of additional benefit since the high SNR available at 3.0T allows for higher spatial resolution without prolongation of measurement time.
authors.affiliation: Institute of Neuroradiology, University of Frankfurt, Germany. jochen.gaa@kgu.de
authors.forename: J
authors.initials: J
authors.lastname: Gaa
authors.forename: S
authors.initials: S
authors.lastname: Weidauer
authors.forename: M
authors.initials: M
authors.lastname: Requardt
authors.forename: B
authors.initials: B
authors.lastname: Kiefer
authors.forename: H
authors.initials: H
authors.lastname: Lanfermann
authors.forename: F E
authors.initials: FE
authors.lastname: Zanella
mesh_terms: D016477:Artifacts; D002536:Cerebral Arteries / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography / Q000379:methods*