Quantitative analysis of acute myocardial infarct in rat hearts with ischemia-reperfusion using a high-resolution stationary SPECT system.
The purpose of this study was to develop an in vivo imaging protocol for a high-resolution stationary SPECT system, called FASTSPECT, in a rat heart model of ischemia-reperfusion (IR) and to compare 99mTc-sestamibi imaging and triphenyltetrazolium chloride (TTC) staining for reliability and accuracy in the measurement of myocardial infarcts.


METHODS
FASTSPECT consists of 24 modular cameras and a 24-pinhole aperture with 1.5-mm spatial resolution and 13.3 cps/microCi (0.359 cps/kBq) sensitivity. The IR heart model was created by ligating the left coronary artery for 90 min and then releasing the ligature for 30 min. Two hours after 99mTc-sestamibi injection (5-10 mCi [185-370 MBq]), images were acquired for 5-10 min for 5 control rats and 11 IR rats. The hearts were excised, and the left ventricle was sectioned into 4 slices for TTC staining.


RESULTS
Left and right ventricular myocardium in control rats was shown clearly, with uniform 99mTc-sestamibi distribution and 100% TTC staining for viable myocardium. Nine of 11 rats with IR survived throughout imaging and exhibited 50.8% +/- 2.7% ischemic area and 37.9% +/- 3.9% infarct in the left ventricle on TTC staining. The infarct size measured by FASTSPECT imaging was 37.6% +/- 3.6%, which correlated significantly with that measured by TTC staining (r = 0.974; P < 0.01).


CONCLUSIONS
The results confirmed the accuracy of FASTSPECT imaging for measurement of acute myocardial infarcts in rat hearts. Application of FASTSPECT imaging in small animals may be feasible for investigating myocardial IR injury and the effects of revascularization.
Liu
Zhonglin
Z
Department of Radiology, University of Arizona Health Sciences Center, Tucson 85724-5067, USA. zliu@radiology.arizona.edu
Kastis
George A
GA
Stevenson
Gail D
GD
Barrett
Harrison H
HH
Furenlid
Lars R
LR
Kupinski
Matthew A
MA
Patton
Dennis D
DD
Wilson
Donald W
DW
D000818:Animals; D004396:Coloring Agents; D007091:Image Processing, Computer-Assisted; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000000981:diagnostic imaging* / Q000473:pathology; D009206:Myocardium / Q000473:pathology; D019275:Radiopharmaceuticals; D051381:Rats; D017207:Rats, Sprague-Dawley; D013194:Staining and Labeling; D017256:Technetium Tc 99m Sestamibi; D013778:Tetrazolium Salts; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D004396:Coloring Agents; D019275:Radiopharmaceuticals; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D017256:Technetium Tc 99m Sestamibi