MR imaging of reperfused myocardial infarction: comparison of necrosis-specific and intravascular contrast agents in a cat model.
OBJECTIVE
To compare T2-weighted and Gadomer-17- and bis-gadolinium mesoporphyrins-enhanced magnetic resonance (MR) images for distinguishing reversibly from irreversibly damaged myocardium in a cat model of reperfused myocardial infarction.


METHODS
Twelve cats underwent 90 minutes of occlusion and 90 minutes of reperfusion of the left anterior descending coronary artery. After baseline T1- and T2-weighted MR images were obtained, Gadomer-17-enhanced and bis-gadolinium mesoporphyrins-enhanced T1-weighted images were sequentially obtained for 6 hours and 2 hours, respectively. After MR imaging, all cats were sacrificed for 2,3,5-triphenyltetrazolium chloride (TTC) histochemical tissue staining. Areas of abnormal signal intensity on T2-weighted and Gadomer-17-enhanced and bis-gadolinium mesoporphyrins-enhanced T1-weighted MR images were compared with the areas of infarction seen at TTC histochemical staining by using repeated-measures two-way analysis of variance, linear regression analysis, and Bland-Altman analysis.


RESULTS
Mean areas of abnormally high signal intensity on T2-weighted and Gadomer-17-enhanced T1-weighted MR images (43.9% of the left ventricular surface area +/- 11.9 [SD] and 37.7% +/- 10.1, respectively) were significantly larger than the mean area of myocardial infarction at TTC staining (25.7% +/- 12.5) (P <.001). However, there was excellent correlation between the size of an enhancing area on bis-gadolinium mesoporphyrins-enhanced T1-weighted MR images and that of myocardial infarction at TTC staining (r = 0.916, P <.001).


CONCLUSIONS
bis-Gadolinium mesoporphyrins-enhanced T1-weighted MR images accurately reflect the area of infarction, whereas the size of infarction is overestimated on T2-weighted and Gadomer-17-enhanced T1-weighted MR images, which seem to depict the periinfarct area as well as the infarct area.
Lee
Seung Soo
SS
Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1 Poongnap-Dong, Songpa-Ku, Seoul 138-736, Korea.
Goo
Hyun Woo
HW
Park
Sung Bin
SB
Lim
Chung Hwan
CH
Gong
Gyungyub
G
Seo
Joon Beom
JB
Lim
Tae-Hwan
TH
D000704:Analysis of Variance; D000818:Animals; D002415:Cats; D003287:Contrast Media / Q000008:administration & dosage; D004195:Disease Models, Animal; D005682:Gadolinium / Q000008:administration & dosage; D007275:Injections, Intravenous; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008665:Metalloporphyrins / Q000008:administration & dosage; D008854:Microscopy, Electron; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000473:pathology; D009336:Necrosis
D003287:Contrast Media; D008665:Metalloporphyrins; C112663:gadolinium mesoporphyrin; C402765:gadomer 17; D005682:Gadolinium