title: Direct comparison of myocardial perfusion cardiovascular magnetic resonance sequences with parallel acquisition.
abstract: OBJECTIVE
  To directly compare the three main myocardial perfusion cardiovascular magnetic resonance (CMR) sequences incorporating parallel acquisition methods.
  
  
  METHODS
  In 15 subjects (12 men, 57 +/- 15.7 years) referred for diagnostic coronary angiography, we acquired first-pass perfusion images (0.1 mmol/kg gadolinium-DTPA) at rest and during adenosine (140 microg/kg/min) on three separate occasions using three sequences incorporating parallel acquisition methods and approximately equivalent spatiotemporal resolution: hybrid echo planar imaging (hEPI), steady-state free precession (SSFP), and gradient echo imaging (GRE). We calculated the contrast-to-noise ratio (CNR) of each scan and blinded observers scored the presence and severity of artifacts (1, worst to 4, best), diagnostic confidence (0, low to 2, high), transmurality, area, and epicardial vessel territory of perfusion defects.
  
  
  RESULTS
  CNR was greatest with SSFP and least with hEPI (13.15 vs 7.85 P < 0.001). The most artifacts were recorded with SSFP and least with hEPI (2.00 vs 3.03 P < 0.001). Observers were significantly more confident in reporting hEPI images (1.6 hEPI vs 0.9 SSFP, P < 0.001). Results for GRE were intermediate for all assessments.
  
  
  CONCLUSIONS
  The hEPI sequence scored best for diagnostic performance despite the SSFP sequence having greater CNR. This trial favors hEPI for clinical myocardial perfusion CMR and suggests CNR should not be the sole criterion used to gauge the best candidate sequence.
authors.affiliation: Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Lyne
authors.forename: Peter D
authors.initials: PD
authors.lastname: Gatehouse
authors.forename: Ravi G
authors.initials: RG
authors.lastname: Assomull
authors.forename: Gillian C
authors.initials: GC
authors.lastname: Smith
authors.forename: Peter
authors.initials: P
authors.lastname: Kellman
authors.forename: David N
authors.initials: DN
authors.lastname: Firmin
authors.forename: Dudley J
authors.initials: DJ
authors.lastname: Pennell
mesh_terms: D016477:Artifacts; D003287:Contrast Media; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA