Abstract 20590: Characterization of Peri-Infarct Zone by Cardiac Magnetic Resonance: Validation Compared to Ex-vivo Imaging and Post-Mortem Histology
Background: Assessment of peri infarct zone (PIZ) by late gadolinium enhancement (LGE) is limited by the spatial resolution of invivo LGE in the z direction, Resultsing in partial volume effect. Although the assessment of infarct size by LGE has been validated, characterization of PIZ has not been corroborated against histopathological findings.
Objectives: We seek to characterize the PIZ by LGE in comparison with histology in an ischemia reperfusion model of myocardial infarction (MI).
Methods: Adult sheep (35–40kg) were subjected to ischemia reperfusion injury (LAD for 45 min). Six animals underwent invivo CMR 10 days after surgery and were euthanized on the next day for exvivo CMR and histopathological examination. Invivo CMR included: black blood T2 and 2D LGE (in plane resolution 2mm). Animals were euthanized 10 min after injection of gadolinium and heart specimens were sliced and imaged exvivo using a high resolution 3D LGE (isotropic resolution 0.6mm). Heart specimens were then fixed for histological analysis (HE and Masson trichrome).
Results: Infarct and PIZ mass were measured of the invivo and exvivo LGE using a previously described criterion (FWH 50%). Invivo MI size (mean 7.58±4.59g) and exvivo MI size (7.26±4.4g) showed strong correlation (R2=0.99, p<0.001) and agreement (figure1AB). Invivo (4.31±2.65g) and exvivo PIZ mass (4.12g±2.31g) were not different (p=NS) (Figure1F) and were strongly correlated (R2=0.87, p=0.006, Figure1CD). Morphology and distribution of MI and PIZ (n=6) by exvivo 3D LGE correlated well with matching short axis pathologic sections (Figure1E). Superimposed 3D LGE and pathologic images demonstrated that the PIZ consisted in a layer of viable myocardium.
Conclusion: CMR imaging of PIZ compares favorably with histology. Clinically available 2D LGE technique provides robust measurement of infarct size and PIZ. The agreement between invivo 2D and exvivo 3D LGE suggests that slice thickness has no relevant effect on PIZ measurement.
- © 2010 by American Heart Association, Inc.