title: View-sharing in keyhole imaging: Partially compressed central k-space acquisition in time-resolved MRA at 3.0 T.
abstract: BACKGROUND
  Time-resolved contrast-enhanced magnetic resonance (MR) angiography (CEMRA) of the intracranial vasculature has proved its clinical value for the evaluation of cerebral vascular disease in cases where both flow hemodynamics and morphology are important. The purpose of this study was to evaluate a combination of view-sharing with keyhole imaging to increase spatial and temporal resolution of time-resolved CEMRA at 3.0 T.
  
  
  METHODS
  Alternating view-sharing was combined with randomly segmented k-space ordering, keyhole imaging, partial Fourier and parallel imaging (4DkvsMRA). 4DkvsMRA was evaluated using varying compression factors (80-100) resulting in spatial resolutions ranging from (1.1×1.1×1.4) to (0.96×0.96×0.95) mm3 and temporal resolutions ranging from 586 ms/dynamic scan--288 ms/dynamic scan in three protocols in 10 healthy volunteers and seven patients (17 subjects). DSA correlation was available in four patients with cerebral arteriovenous malformations (cAVMs) and one patient with cerebral teleangiectasia.
  
  
  RESULTS
  4DkvsMRA was successfully performed in all subjects and showed clear depiction of arterial and venous phases with diagnostic image quality. At the maximum view-sharing compression factor (=100), a "flickering" artefact was observed.
  
  
  CONCLUSIONS
  View-sharing in keyhole imaging allows for increased spatial and temporal resolution in time-resolved MRA.
authors.affiliation: University of Bonn, Department of Radiology, Sigmund-Freud-Straße 25, 53127 Bonn, Germany. Dariusch.Hadizadeh@ukb.uni-bonn.de
authors.forename: Dariusch R
authors.initials: DR
authors.lastname: Hadizadeh
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.forename: Gabriele
authors.initials: G
authors.lastname: Beck
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Geerts
authors.forename: Guido M
authors.initials: GM
authors.lastname: Kukuk
authors.forename: Azize
authors.initials: A
authors.lastname: Boström
authors.forename: Horst
authors.initials: H
authors.lastname: Urbach
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.forename: Winfried A
authors.initials: WA
authors.lastname: Willinek
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D016477:Artifacts; D016022:Case-Control Studies; D003287:Contrast Media; D044962:Data Compression; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D002538:Intracranial Arteriovenous Malformations / Q000175:diagnosis* / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media