title: Comparison of Gated and Ungated Black-Blood Fast Spin-echo MRI of Carotid Vessel Wall at 3T.
abstract: OBJECTIVE
  Multi-slice ungated double inversion recovery has been proposed as an alternative time-efficient and effective sequence for black-blood carotid imaging. The purpose of this study is to evaluate the comparative repeatability of this multi-contrast sequence with respect to a single slice double inversion recovery prepared gated sequence.
  
  
  METHODS
  Ten healthy volunteers and three patients with Doppler ultrasound defined carotid artery stenosis >30% were recruited. T1-weighted (T1W) and T2W fast spin-echo (FSE) images were acquired centered at the carotid bifurcation with and without cardiac gating. Repeat imaging was performed without patient repositioning to determine the variations in vessel wall measurement and signal intensity due to gating, while negating variations as a result of slice misalignment and anatomical displacement relative to the receiver coil. The distributions and the repeatability of lumen area, vessel wall area, signal and contrast-to-noise ratio (SNR/CNR) of the vessel wall and adjacent muscle were reported.
  
  
  RESULTS
  The T1W ungated sequence generally had comparable wall SNR/CNR with respect to the gated sequence, however the muscle SNR was lower (P = 0.013). The T2W ungated multi-slice sequence had lower SNR/CNR than the gated single slice sequence (P < 0.001), but with equivalent effective wall CNR (P = 0.735). Vessel area measurements using the gated/ungated sequences were equivalent. Ungated sequences had better repeatability in SNR/CNR than the gated sequences with borderline and statistically significant differences. The repeatability of T2W wall area measurement was better using the ungated sequences (P = 0.02), and the repeatability of the remaining vessel area measurements were equivalent.
  
  
  CONCLUSIONS
  Ungated sequences can achieve comparable SNR/CNR and equivalent carotid vessel area measurements than gated sequences with improved repeatability of SNR/CNR. Ungated sequences are good alternatives of gated sequences for vessel area measurement and plaque composition quantification.
authors.affiliation: University Department of Radiology, University of Cambridge.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhu
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Graves
authors.forename: Umar
authors.initials: U
authors.lastname: Sadat
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Young
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Patterson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult