BACKGROUND: Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. METHODS AND RESULTS: Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. DeltaR1 ratio (DeltaR1(myocardium)/DeltaR1(blood)) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20+/-0.15) than in normal myocardium (0.47+/-0.05, P<0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA-enhanced region on day 2 was larger (32.8+/-0.9%) than true infarction as demonstrated by triphenyltetrazolium chloride (TTC) (24.6+/-1.4%, P<0.001, r=0.21). Bland-Altman analysis revealed that the Gd-DTPA-enhanced region overestimated true infarct size by 7.8+/-5.9%. On the other hand, the mesoporphyrin-enhanced region (26.9+/-1.8%, P=NS, r=0.87) and true infarct size were identical. The difference in the areas demarcated by the 2 agents is the peri-infarction. Systolic and diastolic MR images revealed no wall thickening in the mesoporphyrin-enhanced region (0.3+/-3.3%) but reduced thickening in the Gd-DTPA-enhanced rim (8.5+/-5.5%, P<0.05). CONCLUSIONS: The Gd-DTPA-enhanced region encompasses both viable and nonviable portions of the ischemically injured myocardium. The Gd-DTPA-enhanced area overestimated infarct size, but the mesoporphyrin-enhanced area matched true infarct size. The salvageable peri-infarction zone can be characterized with double-contrast-enhanced and functional MR imaging; the mismatched area of enhancement between the 2 agents shows residual wall thickening.
BACKGROUND: Because ischemically injured myocardium is frequently composed of viable and nonviable portions, a method to discriminate the two is useful for clinical management. METHODS AND RESULTS: Ischemically injured myocardium was characterized with extracellular nonspecific (Gd-DTPA) and necrosis-specific (mesoporphyrin) MR contrast media in rats. Relaxation rates (R1) were measured on day 1 and day 2 by inversion-recovery echoplanar imaging. Spin-echo imaging was used to define contrast-enhanced regions and regional wall thickening. Gadolinium concentration, area at risk, and infarct size were measured at postmortem examination. DeltaR1 ratio (DeltaR1(myocardium)/DeltaR1(blood)) after administration of Gd-DTPA was greater in ischemically injured myocardium (1.20+/-0.15) than in normal myocardium (0.47+/-0.05, P<0.05), which was attributed to differences in gadolinium concentration and water content. The Gd-DTPA-enhanced region on day 2 was larger (32.8+/-0.9%) than true infarction as demonstrated by triphenyltetrazolium chloride (TTC) (24.6+/-1.4%, P<0.001, r=0.21). Bland-Altman analysis revealed that the Gd-DTPA-enhanced region overestimated true infarct size by 7.8+/-5.9%. On the other hand, the mesoporphyrin-enhanced region (26.9+/-1.8%, P=NS, r=0.87) and true infarct size were identical. The difference in the areas demarcated by the 2 agents is the peri-infarction. Systolic and diastolic MR images revealed no wall thickening in the mesoporphyrin-enhanced region (0.3+/-3.3%) but reduced thickening in the Gd-DTPA-enhanced rim (8.5+/-5.5%, P<0.05). CONCLUSIONS: The Gd-DTPA-enhanced region encompasses both viable and nonviable portions of the ischemically injured myocardium. The Gd-DTPA-enhanced area overestimated infarct size, but the mesoporphyrin-enhanced area matched true infarct size. The salvageable peri-infarction zone can be characterized with double-contrast-enhanced and functional MR imaging; the mismatched area of enhancement between the 2 agents shows residual wall thickening.
Authors: Alexander Stork; Gunnar K Lund; Kai Muellerleile; Paul M Bansmann; Claus Nolte-Ernsting; Joern Kemper; Philipp G C Begemann; Gerhard Adam Journal: Eur Radiol Date: 2006-04-20 Impact factor: 5.315
Authors: Kai Uwe Juergens; Peter Reimer; Thomas Peter Weber; Bernd Tombach; Christoph Bremer; Bernhard Renger; Hugo Van Aken; Walter Heindel Journal: Int J Cardiovasc Imaging Date: 2005 Apr-Jun Impact factor: 2.357
Authors: Frank M Bengel; Richard T George; Karl H Schuleri; Albert C Lardo; Kai C Wollert Journal: Eur Heart J Cardiovasc Imaging Date: 2013-05-29 Impact factor: 6.875
Authors: Sophia Hammer-Hansen; Steve W Leung; Li-Yueh Hsu; Joel R Wilson; Joni Taylor; Anders M Greve; Jens Jakob Thune; Lars Køber; Peter Kellman; Andrew E Arai Journal: JACC Cardiovasc Imaging Date: 2016-09-21