title: Rapid and accurate determination of relative infarct size in humans using contrast-enhanced magnetic resonance imaging.
abstract: BACKGROUND
  In clinical routine, rapid infarct sizing techniques are warranted, as objective and precise infarct sizing is important for clinical decision-making. Accurate and objective measures of relative infarct size (rIS) using contrast-enhanced cardiac magnetic resonance (ceCMR) have been extensively demonstrated in experimental animals, but less in humans. The aim of this study was therefore to quantify rIS assessed by ceCMR in patients with chronic myocardial infarction using semi-automatic quantitation techniques.
  
  
  METHODS
  A total of 62 patients (mean age 66 +/- 9 years) with ischemic cardiomyopathy (EF 24 +/- 8%) underwent ceCMR for viability testing. rIS was obtained by two time-saving semi-automatic thresholding methods based on: (1) visual definition of a single signal intensity cutoff value (VISUAL) and (2) the full-width-at-half-maximum technique (FWHM). Results were compared to manual tracing (MANUAL) as the reference standard.
  
  
  RESULTS
  VISUAL showed better agreement [r = 0.99; intraclass correlation coefficient (ICC) = 0.98, limits of agreement +/-3.2%] to MANUAL than the FWHM technique (r = 0.77, ICC = 0.76, limits of agreement +/-12%). Infarct sizing using MANUAL was twice as time-consuming (3.1 +/- 0.2 min) compared to VISUAL (1.6 +/- 0.1 min) or FWHM (1.6 +/- 0.2 min).
  
  
  CONCLUSIONS
  Visual estimation of signal intensity cutoff values allows rapid and accurate determination of rIS in patients with chronic myocardial infarction using ceCMR and is superior to the FWHM technique.
authors.affiliation: Medical Clinic I, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Mirja
authors.initials: M
authors.lastname: Neizel
authors.forename: Marcus
authors.initials: M
authors.lastname: Katoh
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Schade
authors.forename: Tienush
authors.initials: T
authors.lastname: Rassaf
authors.forename: Gabriele A
authors.initials: GA
authors.lastname: Krombach
authors.forename: Malte
authors.initials: M
authors.lastname: Kelm
authors.forename: Harald P
authors.initials: HP
authors.lastname: Kühl
mesh_terms: D000368:Aged; D009202:Cardiomyopathies / Q000150:complications / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis*
chemical_list: D003287:Contrast Media