Determining the extent to which delayed-enhancement images reflect the partition-coefficient of Gd-DTPA in canine studies of reperfused and unreperfused myocardial infarction

✍ Scribed by Rebecca E. Thornhill; Frank S. Prato; Gerald Wisenberg; Gerald R. Moran; Jane Sykes

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 621 KB
• Volume: 52
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20236

✦ Synopsis

Abstract

MRI after a constant infusion (CI) of Gd‐DTPA has been used to identify the extent of myocardial infarction (MI). However, Gd‐DTPA‐enhanced “viability” imaging is more commonly performed with a bolus (for “delayed‐enhancement” (DE) imaging). This study sought to determine how image delay time and time postinfarction influence the assessment of necrosis by DE. Both infusion and DE imaging was performed in dogs with reperfused (N = 6) or unreperfused (N = 4) MI. Estimates of the partition‐coefficient of Gd‐DTPA (λ) with DE were compared with those calculated after 60 min of infusion, and the comparisons were repeated until 4 (reperfused) or 8 (unreperfused) weeks postinfarction. In reperfused animals, the concordance (R~c~) between DE and infusion estimates of λ was > 0.90 for most image delays > 8 min postinjection, for day 0 through week 3, with R~c~ at day 0 greater than at week 4 (P = 0.022). In unreperfused animals, there was an interaction between image delay time and time postinfarction (P < 0.001): R~c~ > 0.90 corresponded to longer image delays at week 1 than at weeks 4–8. Therefore, when image delays are selected appropriately, DE images can strongly reflect λ and identify irreversibly injured myocardium. Magn Reson Med 52:1069–1079, 2004. © 2004 Wiley‐Liss, Inc.