title: Semi-automatic quantification of myocardial infarction from delayed contrast enhanced magnetic resonance imaging.
abstract: OBJECTIVE
  Accurate and reproducible assessment of myocardial infarction is important for treatment planning in patients with ischemic heart disease. This study describes a novel method to quantify myocardial infarction by semi-automatic delineation of hyperenhanced myocardium in delayed contrast enhanced (DE) magnetic resonance (MR) images.
  
  
  METHODS
  The proposed method automatically detects the hyperenhanced tissue by first determining the signal intensity of non-enhanced myocardium. A fast level set algorithm was used to limit the heterogeneity of the hyperenhanced regions, and to exclude small regions that constitute noise rather than infarction. The method was evaluated in 40 patients; 20 with acute infarction and 20 with chronic healed infarction using scanners from two different manufacturers. Infarct size measured by the proposed semi-automatic method was compared with manual measurements from three experienced observers. The software used is freely available for research purposes at http://segment.heiberg.se.
  
  
  RESULTS
  The difference in infarct size between semi-automatic quantification and the mean of the three observers was 6.1+/-6.6 ml (mean+/-SD), and the interobserver variability (SD) was 4.2 ml.
  
  
  CONCLUSIONS
  The method presented is a highly automated method for analyzing myocardial viability from DE-MR images. The bias of the method is acceptable and the variability is in the same order of magnitude as the interobserver variability for manual delineations.
authors.affiliation: Department of Clinical Physiology, Lund University Hospital, Sweden. einar.heiberg@med.lu.se
authors.forename: Einar
authors.initials: E
authors.lastname: Heiberg
authors.forename: Henrik
authors.initials: H
authors.lastname: Engblom
authors.forename: Jan
authors.initials: J
authors.lastname: Engvall
authors.forename: Erik
authors.initials: E
authors.lastname: Hedström
authors.forename: Martin
authors.initials: M
authors.lastname: Ugander
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001330:Electronic Data Processing; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D015588:Observer Variation; D012720:Severity of Illness Index; D012984:Software; D014022:Tissue Survival