title: Ultra low-dose of gadobenate dimeglumine for late gadolinium enhancement (LGE) imaging in acute myocardial infarction: a feasibility study.
abstract: OBJECTIVE
  To assess the feasibility of using an ultra-low dose (0.05 mmol/kg of body weight [BW]) of high relaxivity contrast agent for late gadolinium enhancement (LGE) imaging in patients with acute myocardial infarction (AMI).
  
  
  METHODS
  17 consecutive patients (mean age, 60.1 ± 10.3 years) with ST-segment elevation AMI underwent two randomized cardiac magnetic resonance studies (exam intervals between 24 and 48h) on a 1.5T unit during the first week after the event using gadobenate dimeglumine (Gd-BOPTA) at the dose of 0.1 mmol/kg BW (standard dose or SD group) and 0.05 mmol/kg BW (half dose or HD group). Image quality was qualitatively assessed. Quantitative analysis of LGE were performed by measuring signal intensity (SI), signal-to-noise ratio (SNR) in the infarcted myocardium (IM), non-infarcted myocardium (N-IM) and left ventricular cavity (LVC) in images acquired at 1, 3, 5, 10, 15 and 20 min after administration of Gd-BOPTA using both contrast media protocol. Contrast-to-noise ratio (CNR) between IM and N-IM (CNR IM/N-IM) and between IM and LVC (CNR IM/LVC) were also quantified for each time point. Moreover the extent of infarcted myocardium was measured.
  
  
  RESULTS
  102 LGE images were evaluated for each dose group. Quality score was significantly higher for SD at 1, 15 and 20 min (0.002<p<0.046) and for HD at 5 min (p=0.013). SNR has been higher in the SD group compared to the HD group even though not statistically significant at any time-point for both IM (SD vs. HD: 87.7 ± 73 vs. 65 ± 66; 0.15<p<0.38) and N-IM (SD vs. HD: 22 ± 61 vs. 9.9 ± 6.5; 0.09<p<0.43). LVC SNR was significantly higher with SD at 10 min (p=0.03), 15 min (p=0.001) and 20 min (p=0.004). CNR between the IM and N-IM was significantly higher using SD compared to HD (1382.24 ± 1049 vs. 695.4 ± 500; 0.000<p<0.028) at 10, 15 and 20 min. No significant differences in CNR IM/LVC were noted for HD acquired 5 min after CM administration compared to SD acquired at 10 (p=0.34), 15 (p=0.96) and 20 (p=0.41) min, and between HD at 10 min compared to SD acquired at 15 min (p=0.78) and 20 min (p=0.32). Good correlation between SD and HD (0.56<r(2)<0.85, p<0.024) was found at all time-points in the measuring of IA.
  
  
  CONCLUSIONS
  The use of a 0.05 mmol/kg dose of gadobenate dimeglumine is feasible for LGE imaging of acute MI and the best image quality is obtained at 5 min after contrast administration. It could be beneficial in patient with renal failure and a solution to improve the identification of subendocardial infarction reducing examination time, costs and total gadolinium load. However, the standard dose of 0.1 mmol/kg provides overall better image quality, with the best performance obtained at the delay of 10 min or more after Gd-BOPTA administration, and it should be routinely preferred.
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: nicola.galea@uniroma1.it.
authors.forename: Nicola
authors.initials: N
authors.lastname: Galea
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: marco.francone@uniroma1.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Francone
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: f.zaccagna@gmail.com.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Zaccagna
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: federica.ciolina@gmail.com.
authors.forename: Federica
authors.initials: F
authors.lastname: Ciolina
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: davidrum@yahoo.it.
authors.forename: David
authors.initials: D
authors.lastname: Cannata
authors.affiliation: Service de Radiologie et Imagerie Cardiovasculaire, Hôpital Cardiologique, Centre Hospitalier Régional et Universitaire de Lille, Avenue Oscar Lambret, 59037 Lille Cedex, France. Electronic address: emanuela_algeri@yahoo.com.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Algeri
authors.affiliation: Department of Cardiovascular, Respiratory, Nephrologic, Anestesiologic and Geriatric Sciences, Sapienza University of Rome, Policlinico Umberto I, Via del Policlinico 165, 00161 Rome, Rome, Italy. Electronic address: luciano.agati@uniroma1.it.
authors.forename: Luciano
authors.initials: L
authors.lastname: Agati
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: carlo.catalano@uniroma1.it.
authors.forename: Carlo
authors.initials: C
authors.lastname: Catalano
authors.affiliation: Department of Radiological Sciences, Pathology and Oncology, Policlinico Umberto I, "Sapienza" University of Rome, Viale Regina Elena 315, 00161 Rome, Italy. Electronic address: iacopo.carbone@uniroma1.it.
authors.forename: Iacopo
authors.initials: I
authors.lastname: Carbone
mesh_terms: D000368:Aged; D003287:Contrast Media; D004305:Dose-Response Relationship, Drug; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009942:Organometallic Compounds
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine
keywords: Anterior wall myocardial infarction; Cardiac imaging techniques; Gd-BOPTA; Image quality enhancement; Magnetic resonance imaging