Head-to-head comparison between delayed enhancement and percent infarct mapping for assessment of myocardial infarct size in a canine model.

Abstract

PURPOSE:

To compare a novel method, percent-infarct-mapping (PIM), with conventional delayed enhancement (DE) of contrast for accurate myocardial viability assessment. Contrary to signal intensity (SI), the longitudinal relaxation-rate enhancement (DeltaR1) is an intrinsic parameter linearly proportional to the concentration of contrast agent (CA). Determining DeltaR1 voxel-by-voxel, after administering an infarct-avid CA, allows determination of per-voxel percentage of infarcted tissue. The feasibility of generating PIM is demonstrated in canine reperfused infarction using an infarct-avid, persistent-CA (PCA), (Gd)(ABE-DTTA). PIM is compared to the DE method using Gd(DTPA), and both to triphenyltetrazolium chloride (TTC) staining histochemistry.

MATERIALS AND METHODS:

In six dogs, 48 hours following closed-chest, 180-minute coronary occlusion, DE imaging was carried out. PCA was administered immediately thereafter. Pixel-by-pixel R1 maps of the entire left ventricle (LV) were generated 48 hours after PCA using inversion-recovery with multiple inversion times. R1, DeltaR1, and percent-infarct values were calculated voxel-by-voxel.

RESULTS:

Significant correlations (P < 0.01, R >or= 0.8) were obtained for percent-infarct-per-slice (PIS) determined by DE or PIM vs. those from corresponding TTC-stained slices. Compared to TTC, DE overestimated PIS by 32 +/- 18%. PIM underestimated PIS by 2.5 +/- 4.9%. Infarction fraction overestimation was 29 +/- 6% of LV by DE, but only 1.0 +/- 2.3% by PIM. Errors with PIM were significantly smaller than those with DE. Infarct area determined by signal intensity was similarly overestimated whether using Gd(DTPA) or Gd(ABE-DTTA).

CONCLUSION:

The DeltaR1-based PIM method is highly reproducible and more accurate than DE for quantifying myocardial viability in vivo.

• Authors: Balázs Ruzsics, Pál Surányi, Pál Kiss, Brigitta C Brott, Ada Elgavish, Tamas Simor, Gabriel A Elgavish
• Journal: Journal of magnetic resonance imaging : JMRI (J Magn Reson Imaging) Vol. 28 Issue 6 Pg. 1386-92 (Dec 2008) ISSN: 1053-1807 [Print] United States
• PMID: 19025946 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural)
• Copyright: (c) 2008 Wiley-Liss, Inc.

Chemical References

• Contrast Media
• Organometallic Compounds
• gadolinium N-(2-butyryloxyethyl)-N'-(2-ethyloxyethyl)-N,N'-bis(N'',N''-bis(carboxymethyl)acetamido)-1,2-ethanediamine
• Pentetic Acid
• Gadolinium DTPA

Topics

• Analysis of Variance
• Animals
• Contrast Media
• Disease Models, Animal
• Dogs
• Gadolinium DTPA
• Image Enhancement (methods)
• Image Processing, Computer-Assisted (methods)
• Magnetic Resonance Imaging (methods)
• Male
• Myocardial Infarction (diagnosis)
• Organometallic Compounds
• Pentetic Acid
• Regression Analysis