MR imaging of acute myocardial infarction in pigs using Gd-DTPA-labeled dextran.
Myocardial infarctions were induced in 12 pigs. In 6 pigs, dextran-(Gd-DTPA)15 (approximately 0.1 mmol Gd/kg b.w.) was injected i.v. 4 to 4.5 hours after coronary artery occlusion. ECG gated MR images were obtained repeatedly before (n = 4) and after (n = 6) contrast medium injection. Relaxation times in blood samples were measured repeatedly. The animals were sacrificed 2 hours after contrast medium administration. The hearts were excised, reexamined in the MR equipment and stained with triphenyltetrazolium chloride (TTC) in order to define areas of infarction. The remaining 6 pigs were sacrificed 6 hours after occlusion without administration of contrast medium. These hearts were only imaged ex vivo. In vivo, the infarctions could not be identified with or without dextran-(Gd-DTPA)15. Ex vivo, without contrast medium, the infarctions had an increased signal intensity, most pronounced in the T2-weighted images. Dextran-(Gd-DTPA)15 caused a prolonged, pronounced shortening of T1 and T2 in blood samples. The infarct demarcation improved in the T1-weighted images after injection of dextran-(Gd-DTPA)15, due to a moderate enhancement in normal myocardium and a stronger enhancement at the periphery of the infarctions, while the central parts of the infarctions were only weakly enhanced.
Wikström
M
M
Department of Diagnostic Radiology, Akademiska Sjukhuset, University of Uppsala, Sweden.
Martinussen
H J
HJ
Wikström
G
G
Ericsson
A
A
Nyman
R
R
Waldenström
A
A
Hemmingsson
A
A
D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D019786:Gadolinium DTPA; D007089:Image Enhancement; D008026:Ligation; D008279:Magnetic Resonance Imaging; D009203:Myocardial Infarction / Q000139:chemically induced / Q000473:pathology*; D004369:Pentetic Acid; D013552:Swine
D003287:Contrast Media; D003911:Dextrans; C075783:dextran-(gadolinium-DTPA)15; D004369:Pentetic Acid; D019786:Gadolinium DTPA