ORAL PRESENTATION Open Access A new CMR protocol for non-destructive, high resolution, ex-vivo assessment of the area at risk simultaneous with infarction: validation with histopathology Lowie M Van Assche*, Han W Kim, Christoph J Jensen, Ki-Young Kim, Michele Parker, Raymond J Kim From 15th Annual SCMR Scientific Sessions Orlando, FL, USA. 2-5 February 2012 Background In the setting of acute myocardial infarction (AMI), the aim of reperfusion and pharmacologic therapies is to salvage areas of ischemic, but reversibly injured myocar- dium within the area-at-risk (AAR). The current histo- pathologic reference standard requires administration of microspheres, destructive sectioning of the heart, the use of tissue stains, and digital photography to delineate the AAR, infarction, and to calculate salvage. We evalu- ated a newly developed CMR protocol that potentially provides non-destructive, high-resolution, ex-vivo assess- ment of the AAR simultaneous with infarction. Methods Four canines underwent 50-minute occlusion of the LAD coronary followed by reperfusion. Imaging was performed 5-days post-AMI. The main goal of the pro- tocol was to create 3 distinct myocardial gadolinium concentrations delineating viable AAR, infarcted AAR and remote myocardium. This was achieved by (1) injecting gadolinium (0.3-0.4mmol/kg) in-vivo to differ- entially accumulate in infarction, (2) providing a wait time to allow washout of gadolinium from viable myo- cardium, (3) injecting another dose of gadolinium prior to sacrifice using the same process as if administering microspheres for determining the AAR by pathology. For validation purposes, microspheres (2-8μm, Thermo- Scientific) were mixed with gadolinium in this step. Finally, (4) the heart was extracted and ex-vivo 3-dimen- sional-delayed-enhancement-CMR imaging was per- formed. The heart was sectioned into short-axis slices and photographed under UV-light to delineate the AAR (absence of microspheres) and after staining with triphe- nyltetrazoliumchloride to delineate infarction. Histo- pathology and ex-vivo-CMR images were analyzed by 2 blinded observers. Results Figure 1 shows histopathology of a subendocardial-AMI with transmural AAR. On the matched delayed- enhancement-CMR image, 3 distinct image intensities are present: (1) myocardium with lowest signal matches location and shape of the viable AAR by microspheres, (2) region with highest signal matches infarction on pathology and (3) remote zone with intermediate signal. On an animal basis, ex-vivo-CMR AAR was similar to that by microspheres (33%±7 vs. 35%±6 respectively, p=0.4). On a slice basis (n=27), there was a strong linear correlation between the ex-vivo-CMR and microsphere- defined AAR (r=0.98, slope=0.96±0.04, p<00001). Simi- larly, CMR infarct size matched that by triphenyltetrazo- liumchloride (r=0.97, p<0.0001). Calculated CMR salvage was also highly correlated with that of histo- pathology (r=0.92, p<0.0001). Conclusions We developed a new CMR protocol that provides high- resolution, ex-vivo images of the AAR simultaneous with infarction in the same 3-dimensional dataset. This can serve as an alternative to histopathology as a truth standard measurement of the AAR and salvage that is non-destructive, allows for multiplanar reconstruction and is automatically registered with the spatial map of infarction.Cardiology, Duke University, Durham, NC, USA Van Assche et al. Journal of Cardiovascular Magnetic Resonance 2012, 14(Suppl 1):O7 http://www.jcmr-online.com/content/14/S1/O7 © 2012 Van Assche et al; licensee 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. http://creativecommons.org/licenses/by/2.0 Funding Funded in part by 5R01HL064726-07. Published: 1 February 2012 doi:10.1186/1532-429X-14-S1-O7 Cite this article as: Van Assche et al.: A new CMR protocol for non- destructive, high resolution, ex-vivo assessment of the area at risk simultaneous with infarction: validation with histopathology. Journal of Cardiovascular Magnetic Resonance 2012 14(Suppl 1):O7. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit Figure 1 Example of sub-endocardial AMI with transmural risk region. Van Assche et al. Journal of Cardiovascular Magnetic Resonance 2012, 14(Suppl 1):O7 http://www.jcmr-online.com/content/14/S1/O7 Page 2 of 2 Background Methods Results Conclusions Funding