Volume 15 Supplement 1

Abstracts of the 16th Annual SCMR Scientific Sessions

Open Access

Myocardial salvage by T2W-CMR: direct comparison to a non-destructive, high resolution, 3-dimensional ex-vivo assessment of the area at risk simultaneous with infarction

  • Lowie M Van Assche1,
  • Christoph J Jensen1,
  • David Wendell1,
  • Michele Parker1,
  • Han W Kim1 and
  • Raymond J Kim1
Journal of Cardiovascular Magnetic Resonance201315(Suppl 1):O15

https://doi.org/10.1186/1532-429X-15-S1-O15

Published: 30 January 2013

Background

The amount of myocardial salvage is a critical determinant of prognosis in acute myocardial infarction (AMI). T2W-CMR in combination with DE-CMR is thought to be a promising method that could presumably measure salvage. However, direct comparisons with the appropriate reference standard are limited. Additionally, even if a pathology reference standard is present, co-registration with in-vivo imaging is problematic. We recently validated a new ex-vivo CMR protocol against the reference standard of microspheres and TTC that provides 3D, non-destructive, high-resolution maps of the AAR simultaneously with infarction[1]. Because this map delineates both the AAR and infarction, salvage can be easily measured in a single image, rather than being calculated from 2 datasets. Additionally, the 3D map allows for direct matching of in-vivo DE to ex-vivo CMR and thereby further minimizing the potential for misregistration from in-vivo DE and more importantly in-vivo T2. Therefore, we sought to compare in-vivo calculated salvage to the directly measured salvage by ex-vivo CMR.

Methods

12 canines underwent variable coronary occlusion of the LAD (45-75min) followed by reperfusion to create a range of myocardial salvage. CMR was performed 5-days post-AMI. T2W-CMR was performed using an optimized DIR-TSE sequence with reduced inter-echo spacing and significantly improved image homogeneity [2]. Following in-vivo imaging, the 3D ex-vivo protocol was performed delineating viable AAR (dark), infarcted AAR (bright) and normal myocardium (grey). Ex-vivo CMR slices were directly matched to in-vivo DE images. In-vivo salvage was calculated by subtracting infarct size by DE from T2-hyperintensity size by TSE and expressed as a percentage of T2-hyperintensity size. For ex-vivo CMR, salvage was directly measured on the matched slices and expressed as a percentage of the AAR.

Results

A total of 51 slices were analyzed. Mean calculated salvage by in-vivo CMR was significantly lower then mean measured salvage by ex-vivo CMR. (3.2% vs 63.6%, respectively, p<0.0001). Figure 1 shows no correlation between in-vivo and ex-vivo CMR (r=-0.08, p=0.55). Conversely, there was a significant correlation between T2 size by in-vivo CMR and scar size by the ex-vivo protocol (r=0.93, p<0.0001). Figure 2 shows examples of in-vivo T2 and DE slices compared with directly marched ex-vivo CMR.

Figure 1

Figure 2

Conclusions

In-vivo calculated salvage did not correspond with directly measured salvage on matched ex-vivo slices. Instead, there was a strong correlation between in-vivo T2 size and ex-vivo scar size.

Funding

Funded in part by 5R01HL064726-07.

Authors’ Affiliations

(1)
Cardiology, Duke University

References

  1. JCMR. 2012, 14 (1): Abstract O7Google Scholar
  2. JCMR. 2012, 14 (1): Abstract O113Google Scholar

Copyright

© Van Assche et al; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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