title: Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging.
abstract: OBJECTIVE
  To investigate whether an extracellular gadolinium-(Gd)-based contrast agent (CA) enters nonperfused myocardium during acute coronary occlusion, and whether nonperfused myocardium presents as hyperintense in delayed contrast-enhanced (DE) MR images in the absence of CA in that region.
  
  
  METHODS
  The left anterior descending coronary artery (LAD) was occluded for 200 minutes in six pigs. The longitudinal relaxation rate (R(1)) in blood, perfused myocardium, and nonperfused myocardium was repeatedly measured using a Look-Locker sequence before and during the first hour after administration of Gd-DTPA-BMA.
  
  
  RESULTS
  While blood and perfused myocardium showed a major increase in R(1) after CA administration, nonperfused myocardium did not. R(1) in nonperfused myocardium was significantly lower than in blood and perfused myocardium during the first hour after CA administration. When the signal from perfused myocardium was nulled, demarcation of the hyperintense nonperfused myocardium was achieved in all of the study animals.
  
  
  CONCLUSIONS
  Gd-DTPA-BMA does not enter ischemic myocardium within one hour after administration during acute coronary occlusion. The ischemic region with complete absence of CA still appears bright when the signal from perfused myocardium is nulled using inversion-recovery DE-MRI. This finding is important for understanding the basic pathophysiology of inversion-recovery viability imaging, as well as for imaging of acute coronary syndromes.
authors.affiliation: Department of Clinical Physiology, Lund University, Lund, Sweden. erik.hedstrom@med.iu.se
authors.forename: Erik
authors.initials: E
authors.lastname: Hedström
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
authors.forename: Rolf
authors.initials: R
authors.lastname: Eriksson
authors.forename: Lars
authors.initials: L
authors.lastname: Johansson
authors.forename: Håkan
authors.initials: H
authors.lastname: Ahlstrom
authors.forename: Tomas
authors.initials: T
authors.lastname: Bjerner
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000494:pharmacology; D003327:Coronary Disease / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D007511:Ischemia / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009203:Myocardial Infarction / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D010477:Perfusion; D013552:Swine; D013997:Time Factors
chemical_list: D003287:Contrast Media; D005682:Gadolinium