Imaging of myocardial infarction: Comparison of magnevist and gadophrin-3 in rabbits

OBJECTIVES This study was designed to determine the enhancement profile of a necrosis-specific contrast agent gadophrin III) in comparison to a standard extracellular agent on T1-weighted (g magnetic resonance (MR) images in acute and chronic myocardial infarctions (MIs). BACKGROUND Contrast-enhanced AIR imaging demonstrated the ability to accurately quantify infarct size; however, some controversies persist about which contrast medium is best suited. METHODS Fifteen rabbits underwent thoracotomy and permanent occlusion of a branch of the left coronary, artery. Two animals died before imaging, eight were examined 48 h after occlusion and five animals were imaged six weeks following induction of infarction. All animals received 50 mumol/kg of gadophrin-3 24 h before the MR examination. Continuous short-axis views were collected using an inversion recovery turbo fast low angle shot sequence. Imaging was, repeated 5 to 10 min following additional injection of 100 mumol/kg of Magnevist. The area of hyperenhancement demarcated following gadophrin-3) injection was, compared with the region of hyperenhancement seen on gadophrin-3 plus Magnevist enhanced image using triphenyltetrazolium chloride (TTC) staining as the standard of reference. RESULTS In acute MI3 the mean difference in size of hyperenhancement seen on the two different in vivo MR scans was - 1.8 +/- 6.0 mm(2) (p > 0.05). Both measurements showed excellent agreement with TTC staining. Chronic MIs showed no enhancement with gadophrin-3, whereas application of Magnevist resulted in hyperenhancement. CONCLUSIONS Standard extracellular contrast agents do not overestimate the size of acute MI. The combination of gadophrin-3 and Magnevist can distinguish acute and chronic myocardial injury because chronic MIs do not enhance with gadophrin-3. (J Am Coll Cardiol 2002;39: 1392-8) (C) 2002 by the American College of Cardiology Foundation.