title: Measurement of myocardium at risk with cardiovascular MR: comparison of techniques for edema imaging.
abstract: OBJECTIVE
  To determine variability and agreement for detecting myocardial edema with T2-weighted short-tau inversion recovery (STIR), acquisition for cardiac unified T2 edema (ACUT2E), T2 mapping, and early gadolinium enhancement (EGE) after successfully reperfused ST-segment-elevation myocardial infarction (STEMI) and diagnostic accuracy of each sequence to predict infarct-related artery (IRA).
  
  
  METHODS
  Local ethics committee approved the study, with patient informed written consent. On day 2 after successful primary angioplasty for STEMI, 53 patients were prospectively enrolled; 40 patients (mean age, 60 years) completed study. Two sets of cardiac magnetic resonance (MR) images were obtained on same day 6 hours apart. Basal, midcavity, and apical sections were obtained with each sequence. Interobserver, intraobserver, and interimage variability (1 minus intraclass correlation coefficient) and agreement (Bland-Altman method) were assessed.
  
  
  RESULTS
  Size of myocardial edema significantly differed. Mean size of myocardium at risk was similar between T2-weighted STIR (18.2 g) and T2 mapping (17.3 g) (P = .54). Mean size differed between T2-weighted STIR (18.2 g) and ACUT2E (14.0 g) (P = .01) and between T2-weighted STIR (18.2 g) and EGE (14.2 g) (P = .003). T2 mapping and EGE had best agreement (interobserver bias: T2-weighted STIR, -0.9 [mean difference] ± 9.6 [standard deviation]; ACUT2E, -2.5 ± 6.9; T2 mapping, -3.8 ± 4.7; EGE, -5.3 ± 5.9; interimage bias: T2-weighted STIR, 1.5 ± 5.8; ACUT2E, -0.8 ± 4.9; T2 mapping, 3.1 ± 4.0; EGE, 1.1 ± 4.9; intraobserver bias: T2-weighted STIR, 1.4 ± 5.8; ACUT2E, 0.6 ± 4.7; T2 mapping, 2.2 ± 3.1; EGE, 1.7 ± 2.9). Variability was lowest for T2 mapping (intraobserver, 0.05; interobserver, 0.09; interimage, 0.1) followed by EGE (intraobserver, 0.03; interobserver, 0.14; interimage, 0.14), with improved detection of territory of IRA versus ACUT2E (intraobserver, 0.11; interobserver, 0.22; interimage, 0.12) and T2-weighted STIR (intraobserver, 0.1; interobserver, 0.32; interimage, 0.1).
  
  
  CONCLUSIONS
  Cardiac MR methods to detect and quantify infarct myocardial edema are not interchangeable; T2 mapping is the most reproducible method, followed by EGE, ACUT2E, and T2-weighted STIR. Clinical trial registration no. NCT01468662
authors.affiliation: From the Bristol Heart Institute (E.J.M., C.B.L., N.M., M.C.K.H., C.B.) and Clinical Trial and Evaluation Unit (M.P., J.M.H.), University of Bristol, Bristol NIHR Cardiovascular Biomedical Research Unit, Level 7 Queens Bldg, Bristol Royal Infirmary, Bristol BS2 8HW, England; Heart Hospital, London, England (J.C.M.); and Siemens Healthcare, Frimley, England (P.J.W.).
authors.forename: Elisa J
authors.initials: EJ
authors.lastname: McAlindon
authors.forename: Maria
authors.initials: M
authors.lastname: Pufulete
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Harris
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Lawton
authors.forename: James C
authors.initials: JC
authors.lastname: Moon
authors.forename: Nathan
authors.initials: N
authors.lastname: Manghat
authors.forename: Mark C K
authors.initials: MC
authors.lastname: Hamilton
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Weale
authors.forename: Chiara
authors.initials: C
authors.lastname: Bucciarelli-Ducci
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D004489:Edema, Cardiac / Q000175:diagnosis*; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology / Q000628:therapy; D009206:Myocardium / Q000473:pathology; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D018570:Risk Assessment
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol