Double-Contrast Enhanced MR Imaging of Myocardial Infarction in the Pig

Abstract

Myocardial infarction was induced by ligating a diagonal branch of the left anterior descending artery in 18 pigs. All pigs were sacrificed 6 h after the occlusion. Dysprosium diethylenetriaminepentaacetic acid bismethylamide (Dy-DTPA-BMA, 1 .O mmol/kg) was administered i.v. to 6 pigs, starting 3 min before sacrifice (injection time approximately 1 min). In a second group of 6 pigs, a double-contrast technique was used, consisting of an i.v. injection of gadolinium-DTPA-BMA (0.4 mmol/kg) 2 h before sacrifice, followed by an i.v. injection of Dy-DTPA-BMA (1.0 mmol/kg) 3 min before sacrifice. Six additional pigs, subjected to 6 h of coronary artery occlusion without administration of contrast medium, served as controls. The hearts were excised and imaged with MR. In the control animals. the infarctions demonstrated an increased signal intensity in the proton density-and T2-weighted images. Administration of Dy-DTPA-BMA primarily improved infarct visualization in the proton density-and T2-weighted images, due to reduction of signal intensity in nonischemic myocardium. The double-contrast technique further improved infarct visualization in all sequences.

MR Imaging of Double-Contrast Enhanced Porcine Myocardial Infarction

“…The current study confirms the results of previous studies that Gd-DTPA-BMA induces an enhanced infarct signal in the T1-and proton densityweighted sequences (12), resulting in improved infarct visualization compared with the situation in which either no contrast agent or Dy-DTPA-BMA was administered (6). In the T2-weighted sequences, edema is probably the main cause of the high infarct signal.…”

“…The administration of the negative contrast agent Dy-DTPA-BMA improved infarction visualization by reducing signal intensity in nonischemic myocardium (7,12). On the other hand, accumulation of Dy-DTPA-BMA in infarcted myocardium does not seem to result in reduced signal intensity, probably because of a homogeneous intra-and extracellular distribution (6) as a result of loss of cell membrane integrity as suggested by KLONER & BRAUNWALD (5) and ERICSSON et al (1).…”

“…A double-contrast technique has previously been applied in MR imaging of the myocardium in a bicompartmental model, where injection of the 2 contrast media at different time points enabled a distribution of Gd-DTPA-BMA predominantly in infarcted tissue and Dy-DTPA-BMA predominantly in nonischemic myocardium (12). In the present study, a unicompartmental model was used, with simultaneous administration of the 2 contrast agents.…”

“…The positive contrast agents Gd-DTPA (13) and Gd-DTPA-BMA (12) resulted in stronger enhancement of infarcted myocardium than nonischemic myocardium. The administration of the negative contrast agent Dy-DTPA-BMA improved infarction visualization by reducing signal intensity in nonischemic myocardium (7,12).…”

Contrast-Enhanced MR Imaging of Experimental Acute Tubular Necrosis

“…The simultaneous administration of gadodiamide and sprodiamide injection has been shown to enhance the difference between normal and necrotic tissue in models of myocardial infarction (8, 12, 19), between cells with intact and disrupted cellular membrane in an in vitro system (5), and in induced hepatic necrosis (4).…”