title: Enhanced image quality in black-blood MRI using the improved motion-sensitized driven-equilibrium (iMSDE) sequence.
abstract: OBJECTIVE
  To propose an improved motion-sensitized driven-equilibrium (iMSDE) pulse sequence to enhance the tissue signal-to-noise ratio (SNR) while maintaining the same flow suppression capability in black-blood carotid artery magnetic resonance imaging (MRI).
  
  
  METHODS
  Compared to the traditional MSDE sequence, the iMSDE sequence uses an extra refocusing pulse and two extra gradients to achieve SNR improvement. Computer simulation and phantom studies were used to evaluate both eddy currents and local B(1) inhomogeneity effects on SNR behaviors on both MSDE and iMSDE images. To further assess the SNR improvements brought by iMSDE in vivo, five healthy volunteers were also scanned with both sequences. The paired t-test was used for statistical comparison.
  
  
  RESULTS
  Both simulations and phantom studies demonstrated that eddy currents and local B(1) inhomogeneity will cause image SNR reduction in the MSDE sequence, and that these factors can be partially compensated for with the iMSDE sequence. In vivo comparison showed that the iMSDE sequence significantly improved the tissue-lumen contrast-to-noise ratio (CNR) and static tissue SNR (P < 0.001 for both), while maintaining low lumen SNR in carotid MRI.
  
  
  CONCLUSIONS
  Compared to the traditional MSDE sequence, the iMSDE sequence can achieve improved soft-tissue SNR and CNR in carotid artery MRI without sacrificing flow suppression capability and time efficiency.
authors.affiliation: Department of Radiology, University of Washington, Seattle, Washington, USA. jinnan.wang@philips.com
authors.forename: Jinnan
authors.initials: J
authors.lastname: Wang
authors.forename: Vasily L
authors.initials: VL
authors.lastname: Yarnykh
authors.forename: Chun
authors.initials: C
authors.lastname: Yuan
mesh_terms: D000465:Algorithms; D016477:Artifacts; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009038:Motion; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity