The significance of perfusion defect at myocardial perfusion MR imaging in a cat model of acute reperfused myocardial infarction.
OBJECTIVE
To determine whether the size of a perfusion defect seen at myocardial perfusion MR imaging represents the extent of irreversibly damaged myocardium in acute reperfused myocardial infarction.


METHODS
In nine cats, reperfused myocardial infarction was induced by occlusion of the left anterior descending coronary artery for 90 minutes and subsequent reperfusion for 90 minutes. At single-slice myocardial perfusion MR imaging at the midventricular level using a turbo-FLASH sequence, 60 short-axis images were sequentially obtained with every heart beat after bolus injection of gadomer-17. The size of the perfusion defect was measured and compared with both the corresponding unstained area seen at triphenyl tetrazolium chloride (TTC) staining and the hyperenhanced area seen at gadophrin-2- enhanced MR imaging performed in the same cat six hours after myocardial perfusion MR imaging.


RESULTS
The sizes of perfusion defects seen at gadomer-17-enhanced perfusion MR imaging, unstained areas at TTC staining, and hyperenhanced areas at gadophrin-2-enhanced MR imaging were 20.4+/-4.3%, 29.0+/-9.7%, and 30.7+/- 10.6% of the left ventricular myocardium, respectively. The perfusion defects seen at myocardial perfusion MR imaging were significantly smaller than the unstained areas at TTC staining and hyperenhanced areas at gadophrin-2- enhanced MR imaging (p < .01). The sizes of both the perfusion defect at myocardial perfusion MR imaging and the hyperenhanced area at gadophrin-2- enhanced MR imaging correlated well with the sizes of unstained areas at TTC staining (r = .64, p = .062 and r = .70, p = .035, respectively).


CONCLUSIONS
In this cat model, the perfusion defect revealed by myocardial perfusion MR imaging underestimated the true size of acute reperfused myocardial infarction. The defect may represent a more severely damaged area of infarction and probably has prognostic significance.
Goo
Hyun Woo
HW
Department of Radiology, Asan Medical Center, University of Ulsan Collge of Medicine, Seoul, Korea. thlim@www.amc.seoul.kr
Kim
Dong Hun
DH
Lee
Seoung Soo
SS
Park
Sung Bin
SB
Lim
Tae-Hwan
TH
D000818:Animals; D002415:Cats; D003287:Contrast Media; D005682:Gadolinium; D019786:Gadolinium DTPA; D008279:Magnetic Resonance Imaging; D008652:Mesoporphyrins; D008665:Metalloporphyrins; D009203:Myocardial Infarction / Q000473:pathology* / Q000628:therapy; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000473:pathology
D003287:Contrast Media; D008652:Mesoporphyrins; D008665:Metalloporphyrins; C118579:gadophrin-2; D005682:Gadolinium; D019786:Gadolinium DTPA