title: Mechanism of late gadolinium enhancement in patients with acute myocardial infarction.
abstract: OBJECTIVE
  To investigate the mechanism of late gadolinium enhancement in irreversibly damaged myocardium in patients with acute myocardial infarct by determining kinetics of Gd-DTPA over time.
  
  
  METHODS
  Twenty-nine patients (24 men; 64 +/- 9 years) with acute myocardial infarction were imaged with functional and gadolinium enhanced cardiovascular magnetic resonance (CMR) 18 minutes post 0.2 mmol/kg Gd-DTPA. T1 of blood, remote and enhanced myocardium, as well as microvascular obstruction (MVO) was determined before and 5-40 minutes post contrast injection (Look-Locker), and the partition coefficient (lambda) was calculated.
  
  
  RESULTS
  T1 and lambda were significantly different from 5-40 minutes post contrast in enhanced (lambda = 0.90 +/- 0.09, p < 0.001) compared to remote myocardium (lambda = 0.40 +/- 0.07). lambda achieved a steady state in remote but increased continuously in infarcted myocardium and to an even greater extent in MVO. T1 of enhanced myocardium was higher from 5-15 minutes, equal at 20 minutes and lower 25-40 minutes post contrast compared to blood, indicating a changing contrast between blood and late gadolinium enhancement over time.
  
  
  CONCLUSIONS
  Enhancement in patients with acute infarction is mainly due to an increased lambda, although reduced wash-in-wash-out adds to the effect. Differentiation between blood and enhanced myocardium may be difficult to achieve, if only little differences of T1 are available. Imaging at a later point will restore the contrast.
authors.affiliation: German Heart Institute Berlin, Berlin, Germany. klein@dhzb.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: Thaiz R
authors.initials: TR
authors.lastname: Schmal
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Nekolla
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schnackenburg
authors.forename: Eckart
authors.initials: E
authors.lastname: Fleck
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
mesh_terms: D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology*; D018709:Statistics, Nonparametric; D013997:Time Factors
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA