Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging

✍ Scribed by Erik Hedström; Håkan Arheden; Rolf Eriksson; Lars Johansson; Håkan Ahlstrom; Tomas Bjerner

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 426 KB
• Volume: 24
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.20604

✦ Synopsis

Abstract

Purpose

To investigate whether an extracellular gadolinium‐(Gd)‐based contrast agent (CA) enters nonperfused myocardium during acute coronary occlusion, and whether nonperfused myocardium presents as hyperintense in delayed contrast‐enhanced (DE) MR images in the absence of CA in that region.

Materials and Methods

The left anterior descending coronary artery (LAD) was occluded for 200 minutes in six pigs. The longitudinal relaxation rate (R~1~) in blood, perfused myocardium, and nonperfused myocardium was repeatedly measured using a Look‐Locker sequence before and during the first hour after administration of Gd‐DTPA‐BMA.

Results

While blood and perfused myocardium showed a major increase in R~1~ after CA administration, nonperfused myocardium did not. R~1~ in nonperfused myocardium was significantly lower than in blood and perfused myocardium during the first hour after CA administration. When the signal from perfused myocardium was nulled, demarcation of the hyperintense nonperfused myocardium was achieved in all of the study animals.

Conclusion

Gd‐DTPA‐BMA does not enter ischemic myocardium within one hour after administration during acute coronary occlusion. The ischemic region with complete absence of CA still appears bright when the signal from perfused myocardium is nulled using inversion‐recovery DE‐MRI. This finding is important for understanding the basic pathophysiology of inversion‐recovery viability imaging, as well as for imaging of acute coronary syndromes. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.