Relaxation enhancing properties of MnDPDP in human myocardium

J Magn Reson Imaging. 2004 Dec;20(6):948-52. doi: 10.1002/jmri.20200.


Purpose: To assess magnitude and duration of changes in myocardial longitudinal relaxation rate (R1) in humans following infusion of the manganese (Mn) releasing contrast agent MnDPDP (Mn-dipyridoxyl-diphosphate).

Materials and methods: Fifteen healthy volunteers were divided into three groups. After initial myocardial and liver R1 measurements using an inversion recovery (IR) turbo fast low-angle shot (FLASH) sequence at 1.5 Tesla, the groups were given different doses of intravenous MnDPDP: 5, 10 and 15 micromol/kg body weight, respectively, over 30 minutes. R1 measurements were then repeated at 1, 2, 4, 8, and 24 hours after the infusion ended.

Results: The left ventricular wall R1 prevalue was 0.98 second(-1) (+/-0.04). R1 increased on average (all 15 subjects) 0.41 second(-1) (+/-0.09). The increase was present one hour after the end of the infusion, remained relatively constant the next two hours, and then declined gradually. After 24 hours, there was still a moderate R1 elevation present, with an average R1-value of 1.16 (+/-0.05). There were only small differences in myocardial R1 responses between the three doses investigated, which was contrasted by a marked dose-response in liver tissue.

Conclusion: MnDPDP gave a significant and prolonged rise in myocardial R1 even at a dose of 5 micromol/kg. The R1-values in the myocardium did not increase linearly with higher doses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Contrast Media / administration & dosage
  • Contrast Media / pharmacokinetics
  • Contrast Media / pharmacology*
  • Dose-Response Relationship, Drug
  • Edetic Acid / administration & dosage
  • Edetic Acid / analogs & derivatives*
  • Edetic Acid / pharmacokinetics
  • Edetic Acid / pharmacology*
  • Electrocardiography
  • Female
  • Heart Rate
  • Humans
  • Liver / metabolism
  • Magnetic Resonance Imaging*
  • Male
  • Manganese / pharmacokinetics
  • Myocardial Contraction / drug effects*
  • Myocardium / metabolism
  • Pyridoxal Phosphate / administration & dosage
  • Pyridoxal Phosphate / analogs & derivatives*
  • Pyridoxal Phosphate / pharmacokinetics
  • Pyridoxal Phosphate / pharmacology*


  • Contrast Media
  • Manganese
  • Pyridoxal Phosphate
  • Edetic Acid
  • N,N'-bis(pyridoxal-5-phosphate)ethylenediamine-N,N'-diacetic acid