Effect of hyperosmotic mannitol on magnetic resonance relaxation parameters in reperfused canine myocardial infarction

D. Douglas Miller, Donald L. Johnston, Donna Dragotakes, John B. Newell, Thomas Aretz, Howard L. Kantor, Thomas J. Brady, Robert D. Okada

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

To determine how administration of a hyperosmotic agent alters regional nuclear magnetic resonance (NMR) relaxation parameters and imaging characteristics in ischemic-reperfused myocardium, 7 dogs were infused with mannitol for 15 minutes before and after the release of a 3 hour left anterior descending coronary artery (LAD) occlusion. Nine control animals received normal saline during the 3 hour occlusion and 1 hour reperfusion periods. Normal posterior left ventricular (LV) wall and the ischemic anterior LV wall (risk area) myocardium was sampled for calculation of segmental microsphere myocardial blood flow, % tissue water content, NMR relaxation times (T1, T2) and myocyte ultrastructure using electron microscopy. Mean infarct T1 values were 14% greater than normal segments in saline-treated controls, but only 5% greater after mannitol. The difference in tissue water content between infarcted and normal segments was 4% in saline-treated (83 vs. 79%) compared to 2% in mannitol-treated dogs (79 vs. 77%). T1, T2 and % water content of control infarct segments were greater than treated infarcts (p < 0.01). T1 and T2 rose as occlusion flow fell below 0.5 ml/min/g in control hearts but did not rise until flows were reduced to 0.1 ml/min/g in mannitol-treated hearts. Areas of increased signal in T1 and T2 NMR images correlated well with histochemical infarct volume (r = 0.98, SEE = 1.1 cc) in mannitol-treated dogs, but infarct borders were qualitatively less well-defined than in controls. We concluded that mannitol (1) diminishes tissue edema and reduces NMR relaxation parameters (T1, T2) in infarcted myocardium; and (2) attenuates the rise in T1 and T2 and ultrastructural myocyte injury in ischemic-reperfused myocardium.

Original languageEnglish (US)
Pages (from-to)79-88
Number of pages10
JournalMagnetic Resonance Imaging
Volume7
Issue number1
DOIs
StatePublished - Jan 1 1989
Externally publishedYes

Keywords

  • Mannitol
  • Myocardial infarction
  • Nuclear magnetic resonance

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging

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