Normal and infarcted myocardium: differentiation with cellular uptake of manganese at MR imaging in a rat model.

Abstract

PURPOSE:

To assess whether normal myocardium can be distinguished from infarction at magnetic resonance (MR) imaging with low doses of manganese dipyridoxyl diphosphate (Mn-DPDP).

MATERIALS AND METHODS:

After 1-hour coronary arterial occlusion and 2-hour reperfusion, three groups of eight rats each were injected with 25, 50, or 100 micromol of Mn-DPDP per kilogram of body weight. The longitudinal relaxation rate (R1) in normal myocardium, reperfused infarction, and blood was repeatedly measured at inversion-recovery echo-planar imaging before and for 1 hour after the administration of contrast material. Afterward, several animals from each group were examined at high-spatial-resolution inversion-recovery spin-echo (SE) MR imaging.

RESULTS:

Manganese accumulated in normal myocardium but was cleared from reperfused infarction and blood. One hour after the administration of Mn-DPDP, R1 in normal myocardium (1.53 sec(-1) +/- 0.03, 1.73 sec(-1) +/- 0.03, and 1.94 sec(-1) +/- 0.02, respectively, for 25, 50, and 100 micromol/kg) was significantly (P <.05) faster than that of reperfused infarction (0.99 sec(-1) +/- 0.03, 1.11 sec(-1) +/- 0.03, and 1.48 sec(-1) +/- 0.06). Normal myocardium appeared hyperintense on T1-weighted inversion-recovery SE MR images and was clearly distinguishable from reperfused infarction.

CONCLUSION:

Mn-DPDP-enhanced inversion-recovery echo-planar and SE MR images demonstrated retention of manganese in normal myocardium and clearance of manganese from infarction. Mn-DPDP has characteristics similar to those of widely used thallium and may be useful in the assessment of myocardial viability at MR imaging.

• Authors: J Bremerich, M Saeed, H Arheden, C B Higgins, M F Wendland
• Journal: Radiology (Radiology) Vol. 216 Issue 2 Pg. 524-30 (Aug 2000) ISSN: 0033-8419 [Print] United States
• PMID: 10924581 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

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

Topics

• Analysis of Variance
• Animals
• Contrast Media
• Coronary Disease (complications)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Echo-Planar Imaging
• Edetic Acid (administration & dosage, analogs & derivatives, blood)
• Female
• Follow-Up Studies
• Magnetic Resonance Imaging (methods)
• Manganese (administration & dosage, blood, pharmacokinetics)
• Metabolic Clearance Rate
• Myocardial Infarction (etiology, metabolism)
• Myocardial Reperfusion
• Myocardium (metabolism)
• Pyridoxal Phosphate (administration & dosage, analogs & derivatives, blood)
• Rats
• Rats, Sprague-Dawley