title: Individual component analysis of the multi-parametric cardiovascular magnetic resonance protocol in the CE-MARC trial.
abstract: BACKGROUND
  The CE-MARC study assessed the diagnostic performance investigated the use of cardiovascular magnetic resonance (CMR) in patients with suspected coronary artery disease (CAD). The study used a multi-parametric CMR protocol assessing 4 components: i) left ventricular function; ii) myocardial perfusion; iii) viability (late gadolinium enhancement (LGE)) and iv) coronary magnetic resonance angiography (MRA). In this pre-specified CE-MARC sub-study we assessed the diagnostic accuracy of the individual CMR components and their combinations.
  
  
  METHODS
  All patients from the CE-MARC population (n = 752) were included using data from the original blinded-read. The four individual core components of the CMR protocol was determined separately and then in paired and triplet combinations. Results were then compared to the full multi-parametric protocol.
  
  
  RESULTS
  CMR and X-ray angiography results were available in 676 patients. The maximum sensitivity for the detection of significant CAD by CMR was achieved when all four components were used (86.5%). Specificity of perfusion (91.8%), function (93.7%) and LGE (95.8%) on its own was significantly better than specificity of the multi-parametric protocol (83.4%) (all P < 0.0001) but with the penalty of decreased sensitivity (86.5% vs. 76.9%, 47.4% and 40.8% respectively). The full multi-parametric protocol was the optimum to rule-out significant CAD (Likelihood Ratio negative (LR-) 0.16) and the LGE component alone was the best to rue-in CAD (LR+ 9.81). Overall diagnostic accuracy was similar with the full multi-parametric protocol (85.9%) compared to paired and triplet combinations. The use of coronary MRA within the full multi-parametric protocol had no additional diagnostic benefit compared to the perfusion/function/LGE combination (overall accuracy 84.6% vs. 84.2% (P = 0.5316); LR- 0.16 vs. 0.21; LR+ 5.21 vs. 5.77).
  
  
  CONCLUSIONS
  From this pre-specified sub-analysis of the CE-MARC study, the full multi-parametric protocol had the highest sensitivity and was the optimal approach to rule-out significant CAD. The LGE component alone was the optimal rule-in strategy. Finally the inclusion of coronary MRA provided no additional benefit when compared to the combination of perfusion/function/LGE.
  
  
  BACKGROUND
  Current Controlled Trials ISRCTN77246133.
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. d.ripley@leeds.ac.uk.
authors.forename: David P
authors.initials: DP
authors.lastname: Ripley
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. m.motwani@leeds.ac.uk.
authors.forename: Manish
authors.initials: M
authors.lastname: Motwani
authors.affiliation: Clinical Trials Research Unit, University of Leeds, Clinical Trials Research House, 71-75 Clarendon Rd, Leeds, UK. j.m.b.brown@leeds.ac.uk.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Brown
authors.affiliation: Clinical Trials Research Unit, University of Leeds, Clinical Trials Research House, 71-75 Clarendon Rd, Leeds, UK. j.e.nixon@leeds.ac.uk.
authors.forename: Jane
authors.initials: J
authors.lastname: Nixon
authors.affiliation: Clinical Trials Research Unit, University of Leeds, Clinical Trials Research House, 71-75 Clarendon Rd, Leeds, UK. c.c.everett@leeds.ac.uk.
authors.forename: Colin C
authors.initials: CC
authors.lastname: Everett
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. p.bijsterveld@leeds.ac.uk.
authors.forename: Petra
authors.initials: P
authors.lastname: Bijsterveld
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. neil.maredia@stees.nhs.uk.
authors.forename: Neil
authors.initials: N
authors.lastname: Maredia
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. s.plein@leeds.ac.uk.
authors.forename: Sven
authors.initials: S
authors.lastname: Plein
authors.affiliation: Multidisciplinary Cardiovascular Research Centre (MCRC) & Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK. j.greenwood@leeds.ac.uk.
authors.forename: John P
authors.initials: JP
authors.lastname: Greenwood
mesh_terms: D000368:Aged; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D016277:Ventricular Function, Left