title: Optimizing dose and administration regimen of a high-relaxivity contrast agent for myocardial MRI late gadolinium enhancement.
abstract: OBJECTIVE
  To investigate the time-course of late gadolinium enhancement of infarcted myocardium using gadobenate dimeglumine at different dosages and administration regimens.
  
  
  METHODS
  After institutional review board approval and informed consent, we studied 13 patients (aged 63±11 years) with chronic myocardial infarction. They underwent two gadobenate dimeglumine-enhanced MR examinations (interval 24-48 h) using short-axis inversion-recovery gradient-echo sequences, with the following two different protocols, in randomized order: 0.05 mmol/kg and imaging at the 2.5th, 5th, 7.5th and 10th minute plus 0.05 mmol/kg and imaging at the 12.5th, 15th, 17.5th and 20th minute; the same as before but using 0.1 mmol/kg for both contrast injections. Contrast-to-noise ratios (CNRs) between infarcted myocardium, non-infarcted myocardium and left ventricle cavity were calculated for each time-point (2.5-min steps). Friedman ANOVA was used for comparing the CNR time-course; Wilcoxon test for comparing CNR at the 10th and the 20th minute.
  
  
  RESULTS
  The CNR between infarcted and non-infarcted myocardium obtained at the 20th minute with 0.05 plus 0.05 mmol/kg resulted significantly higher than that obtained at the 10th minute with 0.05 mmol/kg (P=0.033) while not significantly different from that obtained at the 10th (0.1mm/kg) or at the 20th minute with 0.1 plus 0.1 mmol/kg. The CNR between infarcted myocardium and the left ventricle cavity obtained at the 20th minute with 0.05 plus 0.05 mmol/kg resulted significantly higher than all other measured values (P≤0.017).
  
  
  CONCLUSIONS
  Using gadobenate dimeglumine, 0.05 plus 0.05 mmol/kg allows for a higher CNR between infarcted myocardium and the left ventricle cavity allowing for reliable assessment of the sub-endocardial infarctions.
authors.affiliation: Università degli Studi di Milano, Dipartimento di Scienze Medico-Chirurgiche, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Secchi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Leo
authors.forename: Giacomo D E
authors.initials: GD
authors.lastname: Papini
authors.forename: Francesca
authors.initials: F
authors.lastname: Giacomazzi
authors.forename: Marisa
authors.initials: M
authors.lastname: Di Donato
authors.forename: Francesco
authors.initials: F
authors.lastname: Sardanelli
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009206:Myocardium / Q000473:pathology*; D015588:Observer Variation
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA