title: Dynamic changes of edema and late gadolinium enhancement after acute myocardial infarction and their relationship to functional recovery and salvage index.
abstract: BACKGROUND
  Changes in the myocardium in acute ischemia are dynamic and complex, and the characteristics of myocardial tissue on cardiovascular magnetic resonance in the acute setting are not fully defined. We investigated changes in edema and late gadolinium enhancement (LGE) with serial imaging early after acute myocardial infarction, relating these to global and segmental myocardial function at 6 months.
  
  
  RESULTS
  Cardiovascular magnetic resonance scans were performed on 30 patients with ST-elevation--myocardial infarction treated by primary percutaneous coronary intervention at each of 4 time points: 12 to 48 hours; 5 to 7 days; 14 to 17 days; and 6 months. All patients showed edema at 24 hours. The mean volume of edema (% left ventricle) was 37±16 at 24 hours and 39±17 at 1 week, with a reduction to 24±13 (P<0.01) by 2 weeks. Myocardial segments with edema also had increased signal on LGE at 24 hours (κ=0.77; P<0.001). The volume of LGE decreased significantly between 24 hours and 6 months (27±15% versus 22±12%; P=0.002). Of segments showing LGE at 24 hours, 50% showed resolution by 6 months. In segments with such a reduction in LGE, 65% also showed improved wall motion (P<0.0001). The area of LGE measured at 6 months correlated more strongly with troponin at 48 hours (r=0.9; P<0.01) than LGE at 24 hours (r=0.7). The difference in LGE between 24 hours and 6 months had profound effects on the calculation of salvage index (26±21% at 24 hours versus 42±23% at 6 months; P=0.02).
  
  
  CONCLUSIONS
  Myocardial edema is maximal and constant over the first week after myocardial infarction, providing a stable window for the retrospective evaluation of area at risk. By contrast, myocardial areas with high signal intensity in LGE images recede over time with corresponding recovery of function, indicating that acutely detected LGE does not necessarily equate with irreversible injury and may severely underestimate salvaged myocardium.
authors: Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
authors: Erica
authors: E
authors: Dall'Armellina
authors: Nina
authors: N
authors: Karia
authors: Alistair C
authors: AC
authors: Lindsay
authors: Theodoros D
authors: TD
authors: Karamitsos
authors: Vanessa
authors: V
authors: Ferreira
authors: Matthew D
authors: MD
authors: Robson
authors: Peter
authors: P
authors: Kellman
authors: Jane M
authors: JM
authors: Francis
authors: Colin
authors: C
authors: Forfar
authors: Bernard D
authors: BD
authors: Prendergast
authors: Adrian P
authors: AP
authors: Banning
authors: Keith M
authors: KM
authors: Channon
authors: Rajesh K
authors: RK
authors: Kharbanda
authors: Stefan
authors: S
authors: Neubauer
authors: Robin P
authors: RP
authors: Choudhury
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D003287:Contrast Media; D004489:Edema, Cardiac / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005682:Gadolinium; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D009206:Myocardium / Q000473:pathology; D020127:Recovery of Function; D016276:Ventricular Function
chemical_list: D003287:Contrast Media; D005682:Gadolinium