title: Cardiac MRI: estimation of changes in normalized myocardial gadolinium accumulation over time after contrast injection in patients with acute myocarditis and healthy volunteers.
abstract: OBJECTIVE
  An increased normalized gadolinium accumulation (NGA) in the myocardium during early washout has been used for the diagnosis of acute myocarditis (AM). Due to the fact that the pharmacokinetics of contrast agents are complex, time-related changes in NGA after contrast injection are likely. Because knowledge about time-related changes of NGA may improve the diagnostic accuracy of MR, our study aimed to estimate the time course of NGA after contrast injection in patients as well as in healthy volunteers.
  
  
  METHODS
  An ECG-triggered inversion recovery SSFP sequence with incrementally increasing inversion times was repetitively acquired over the 15 minutes after injection of 0.2 Gd-DTPA per kg body weight in a 4-chamber view in 15 patients with AM and 20 volunteers. The T 1relaxation times and the longitudinal relaxation rates (R1) of the myocardium and skeletal musculature were calculated for each point in time after contrast injection. The time course of NGA was estimated based on the linear relationship between R1 and tissue Gd concentration.
  
  
  RESULTS
  NGA decreased over time in the form of a negative power function in patients with AM and in healthy controls. NGA in AM tended to be higher than in controls (p > 0.05).
  
  
  CONCLUSIONS
  NGA rapidly changes after contrast injection, which must be considered when measuring NGA. Although we observed a trend towards higher NGA values in patients with AM with a maximum difference one minute after contrast injection, NGA did not allow us to differentiate patients with AM from healthy volunteers, because the observed differences did not reach a level of significance.
authors.affiliation: Department of Internal Medicine II, University Medical Center of the Johannes Gutenberg University Mainz, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Breuckmann
authors.forename: S
authors.initials: S
authors.lastname: Maderwald
authors.forename: C
authors.initials: C
authors.lastname: Buhr
authors.forename: O
authors.initials: O
authors.lastname: Bruder
authors.forename: T
authors.initials: T
authors.lastname: Schlosser
authors.forename: R
authors.initials: R
authors.lastname: Erbel
authors.forename: J
authors.initials: J
authors.lastname: Barkhausen
authors.forename: K
authors.initials: K
authors.lastname: Nassenstein
mesh_terms: D000208:Acute Disease; D000328:Adult; D055424:Cardiac-Gated Imaging Techniques; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D009200:Myocardial Contraction / Q000502:physiology; D009205:Myocarditis / Q000175:diagnosis*; D009206:Myocardium / Q000473:pathology; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA