title: Myocardial area at risk and salvage measured by T2-weighted cardiovascular magnetic resonance: reproducibility and comparison of two T2-weighted protocols.
abstract: BACKGROUND
  Late gadolinium enhancement (LGE) and T2-weighted cardiovascular magnetic resonance (CMR) provides a means to measure myocardial area at risk (AAR) and salvage. Several T2-weighted CMR sequences are in use, but there is no consensus in terms of which sequence to be the preferred. Therefore, the aim of the present study was to: (1) Assess the reproducibility and (2) compare the two most frequently used T2-weighted CMR protocols for measuring AAR and salvage.
  
  
  METHODS
  91 patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention underwent a CMR scan 1-7 days after initial treatment. Two different T2-weighted protocols, varying in slice thickness and echo time (TE), were applied covering the entire left ventricle (LV) (protocol 1: TE 65 msec and slice thickness 15 mm; protocol 2: TE 100 msec and slice thickness of 8 mm). On a second scan performed 3 months later, infarct size was assessed with a standard LGE sequence. The two protocols were compared in terms of AAR and salvage index. Furthermore, intra- and interobserver reproducibility were assessed.
  
  
  RESULTS
  Protocol 1 measures a larger AAR and salvage index than protocol 2 with a mean difference in AAR of 1±8%LV (p<0.01) and 6±12 g (p<0.01) and salvage index of 0.04±0.12 (p<0.01). Both protocols had a high intra- and interobserver reproducibility with acceptable limits of agreement (6-8%LV and 6-12 g in AAR and 0.06-0.08 in salvage index).
  
  
  CONCLUSIONS
  We report acceptable reproducibility for AAR and salvage index measured by T2-weighted images. Thus CMR is a reliable tool for measuring AAR and salvage index. Protocol 2 (8 mm slice thickness and 100 msec TE) measures slightly smaller AAR than protocol 1 (15 mm slice thickness and 65 msec TE), but the present study does not allow for a clear recommendation of either of the protocols.
authors.affiliation: Department of Cardiology, Rigshospitalet, Copenhagen, Denmark. Jacoblonborg@gmail.com
authors.forename: Jacob
authors.initials: J
authors.lastname: Lønborg
authors.forename: Niels
authors.initials: N
authors.lastname: Vejlstrup
authors.forename: Anders B
authors.initials: AB
authors.lastname: Mathiasen
authors.forename: Carsten
authors.initials: C
authors.lastname: Thomsen
authors.forename: Jan S
authors.initials: JS
authors.lastname: Jensen
authors.forename: Thomas
authors.initials: T
authors.lastname: Engstrøm
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D016009:Chi-Square Distribution; D003287:Contrast Media; D003718:Denmark; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D009206:Myocardium / Q000473:pathology*; D015588:Observer Variation; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol