Value and limitation of gadolinium-DTPA contrast enhancement in the early detection of acute canine myocardial infarction.

This study was performed to determine whether the infarcted myocardium can be distinguished from the nuclear myocardium by gated nuclear magnetic resonance imaging (NMRI) and gadolinium (Gd)-DTPA contrast enhancement in the early hours after coronary artery ligation. Twenty-one dogs were used: three dogs with 3-hr ligation of the left anterior coronary artery (LAD) (group A); six dogs with 3-hr ligation of LAD, followed by 20-30 min of reperfusion (group B); six dogs with 6-hr ligation of LAD (group C); and six dogs with 12-hr ligation of LAD (group D). Gated NMRI was performed at the time of occlusion or reperfusion, followed by intravenous injection of 0.5 mM/kg of Gd-DTPA using a whole body NMR system. The effects of Gd-DTPA on gated NMRI could not be obtained in group A, but significant contrast enhancement after Gd-DTPA administration in T1-weighted image was obtained in four of six dogs in group B, four of six dogs in group C, and five of six dogs in group D. Then NMRI contrast that expresses the signal intensity ratio between the infarcted and normal myocardia showed a significant increase in groups B, C, and D. Thus, gated NMRI with Gd-DTPA has a limitation as to the early detection of acute myocardial infarction, such as in group A, but it may have a supplementary role in the detection of acute myocardial infarction since improved signal intensities between the normal and infarcted myocardium was obtained in groups B, C, and D.(ABSTRACT TRUNCATED AT 250 WORDS)