Early Gadolinium Enhancement for Determination of Area at Risk: A Preclinical Validation Study.
The aim of this study was to determine whether early gadolinium enhancement (EGE) by cardiac magnetic resonance (CMR) in a canine model of reperfused myocardial infarction depicts the area at risk (AAR) as determined by microsphere blood flow analysis.



It remains controversial whether only the irreversibly injured myocardium enhances when CMR is performed in the setting of acute myocardial infarction. Recently, EGE has been proposed as a measure of the AAR in acute myocardial infarction because it correlates well with T2-weighted imaging of the AAR, but this still requires pathological validation.



Eleven dogs underwent 2 h of coronary artery occlusion and 48 h of reperfusion before imaging at 1.5-T. EGE imaging was performed 3 min after contrast administration with coverage of the entire left ventricle. Late gadolinium enhancement imaging was performed between 10 and 15 min after contrast injection. AAR was defined as myocardium with blood flow <2 SD from remote myocardium determined by microspheres during occlusion. The size of infarction was determined with triphenyltetrazolium chloride.



There was no significant difference in the size of enhancement by EGE compared with the size of AAR by microspheres (44.1 ± 15.8% vs. 42.7 ± 9.2%; p = 0.61), with good correlation (r = 0.88; p < 0.001) and good agreement by Bland-Altman analysis (mean bias 1.4 ± 17.4%). There was no difference in the size of enhancement by EGE compared with enhancement on native T1 and T2 maps. The size of EGE was significantly greater than the infarct by triphenyltetrazolium chloride (44.1 ± 15.8% vs. 20.7 ± 14.4%; p < 0.001) and late gadolinium enhancement (44.1 ± 15.8% vs. 23.5 ± 12.7%; p < 0.001).



At 3 min post-contrast, EGE correlated well with the AAR by microspheres and CMR and was greater than infarct size. Thus, EGE enhances both reversibly and irreversibly injured myocardium.
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; Department of Medicine B, The Heart Center, Rigshospitalet, Copenhagen, Denmark.
Sophia
S
Hammer-Hansen
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; Department of Medicine and Radiology, Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky.
Steve W
SW
Leung
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
Li-Yueh
LY
Hsu
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland; Department of Medicine and Radiology, Division of Cardiovascular Medicine, University of California-San Diego, San Diego, California.
Joel R
JR
Wilson
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
Joni
J
Taylor
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
Anders M
AM
Greve
Department of Medicine B, The Heart Center, Rigshospitalet, Copenhagen, Denmark.
Jens Jakob
JJ
Thune
Department of Medicine B, The Heart Center, Rigshospitalet, Copenhagen, Denmark.
Lars
L
Køber
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland.
Peter
P
Kellman
Laboratory for Advanced Cardiovascular Imaging, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland. Electronic address: araia@nih.gov.
Andrew E
AE
Arai
D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000008:administration & dosage*; D003326:Coronary Circulation; D004195:Disease Models, Animal; D004285:Dogs; D005456:Fluorescent Dyes / Q000008:administration & dosage; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging; D008863:Microspheres; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology*; D011237:Predictive Value of Tests; D013997:Time Factors; D014022:Tissue Survival
D003287:Contrast Media; D005456:Fluorescent Dyes; D019786:Gadolinium DTPA
acute myocardial infarction; area at risk; cardiac magnetic resonance; gadolinium enhancement
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