title: Magnetization spoiling in radial FLASH contrast-enhanced MR digital subtraction angiography.
abstract: OBJECTIVE
  To increase the in-plane spatial resolution and image update rates of 2D magnetic resonance (MR) digital subtraction angiography (DSA) pulse sequences to 0.57 × 0.57 mm and 6 frames/sec, respectively, for intracranial vascular disease applications by developing a radial FLASH protocol and to characterize a new artifact, not previously described in the literature, which arises in the presence of such pulse sequences.
  
  
  METHODS
  The pulse sequence was optimized and artifacts were characterized using simulation and phantom studies. With Institutional Review Board (IRB) approval, the pulse sequence was used to acquire time-resolved images from healthy human volunteers and patients with x-ray DSA-confirmed intracranial vascular disease.
  
  
  RESULTS
  Artifacts were shown to derive from inhomogeneous spoiling due to the nature of radial waveforms. Gradient spoiling strategies were proposed to eliminate the observed artifact by balancing gradient moments across TR intervals. The resulting radial 2D MR DSA sequence (2.6 sec temporal footprint, 6 frames/sec with sliding window factor 16, 0.57 × 0.57 mm in-plane) demonstrated small vessel detail and corroborated x-ray DSA findings in intracranial vascular imaging studies.
  
  
  CONCLUSIONS
  Appropriate gradient spoiling in radial 2D MR DSA pulse sequences improves intracranial vascular depiction by eliminating circular banding artifacts. The proposed pulse sequence may provide a useful addition to clinically applied 2D MR DSA scans.
authors.affiliation: Department of Biomedical Engineering, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Parmede
authors.initials: P
authors.lastname: Vakil
authors.forename: Sameer A
authors.initials: SA
authors.lastname: Ansari
authors.forename: Michael C
authors.initials: MC
authors.lastname: Hurley
authors.forename: Himanshu
authors.initials: H
authors.lastname: Bhat
authors.forename: H Hunt
authors.initials: HH
authors.lastname: Batjer
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bendok
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Eddleman
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Carroll
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction / Q000379:methods*; D016477:Artifacts; D020785:Central Nervous System Vascular Malformations / Q000473:pathology*; D002533:Cerebral Angiography / Q000379:methods*; D003287:Contrast Media; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D060526:Magnetic Fields; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media