title: Peri-infarct zone on early contrast-enhanced CMR imaging in patients with acute myocardial infarction.
abstract: OBJECTIVE
  The aims of this study were to evaluate hyperenhanced regions on contrast-enhanced cardiovascular magnetic resonance (CE-CMR) imaging in patients with acute myocardial infarction (AMI) between early contrast-enhanced cardiovascular magnetic resonance (ECE) (2 min) and late contrast-enhanced cardiovascular magnetic resonance (LCE) (10 to 15 min) after gadolinium administration, and to compare the CE-CMR images with area at risk (AAR) derived from T2-weighted (T2W) CMR.
  
  
  BACKGROUND
  Although CE-CMR imaging can demarcate the infarcted myocardium, the value of hyperenhancement in AMI is still in dispute. The size of hyperenhanced regions may vary with time, and overestimation can be often observed with early acquisition.
  
  
  METHODS
  Thirty-four patients with successfully reperfused AMI underwent CMR within 4 days after the event. Myocardial regions as percentage of left ventricular (LV) myocardium were quantified on CE and T2W images. Relative peri-infarct zone was calculated as the difference in hyperenhanced regions between ECE and LCE, normalized to the individual infarct size.
  
  
  RESULTS
  Both ECE and LCE images revealed hyperenhancement in the territory of the infarct-related artery in all patients. The hyperenhanced region on ECE extended transmurally and was consistently larger than that on LCE (39 ± 12% vs. 27 ± 12% of LV myocardium, p<0.001). The relative peri-infarct zone was inversely correlated with the transmurality of infarction (r=-0.59, p<0.001) and the time from symptom to reperfusion (r=-0.46, p<0.01). The hyperenhanced region on ECE was correlated with the T2W CMR-derived AAR (r=0.86, p<0.001) with the average difference of -0.8% and the limits of agreement of ±11.9%.
  
  
  CONCLUSIONS
  ECE depicts ischemically injured but salvaged myocardium, as well as infarcted myocardium in patients with AMI. The myocardium at risk and infarcted myocardium after reperfusion can be retrospectively assessed by the combination of ECE and LCE.
authors.affiliation: Cardiovascular Center, Rakuwakai Otowa Hospital, Kyoto, Japan. matsumoto.hidenari@gmail.com
authors.forename: Hidenari
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Matsuda
authors.forename: Kenichi
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shimada
authors.forename: Mikiko
authors.initials: M
authors.lastname: Mikuri
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hiraoka
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D003287:Contrast Media; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D009206:Myocardium / Q000473:pathology*; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine