Time series analysis of in vivo cardiac MRI-PET image fusion of the human amniotic mesenchymal stem cell (hAMSC) engraftment
https://doi.org/10.1186/1532-429X-16-S1-P358
© Diedrich et al.; licensee BioMed Central Ltd. 2014
Published: 16 January 2014
Keywords
Background
This study developed a system to monitor intensity changes in the cardiac PET-MRI images of transplanted stem cells in vivo. A fusion system, consisting of 2 medical imaging modalities to monitor the changes in signal intensity in regions of interest (ROI) over time, was achieved.
Methods
Porcine ischemia reperfusion (IR) injury model was employed to assess the successful stem cell engraftment signal by manganese enhanced MRI (MEMRI). To validate the MEMRI signal, hAMSCs were transduced by PET reporter gene (RG) utilizing the herpes simplex virus-thymidine kinase transgene construct, which is expressed only in engrafted cells to trap 18F-FHBG radiotracer. One week after IR injury, the RG transduced hAMSCs were delivered via transendocardial injection into peri- and intra-infarct regions. PET-CT and MR locator-MEMRI-delayed enhanced MRI (DEMRI) images were acquired post hAMSC injection on days 0, 7, and 45. All pairs of CT and MR locator images were registered by gradient descent to optimize mutual information between the images generating transformation matrixes. These transformation matrixes were used to align PET with MEMRI and DEMRI and longitudinal images into common frames of reference. Additionally image pairs were fused into a single display. An ROI around the engrafted stem cells on MEMRI was copied to the same location on PET-CT longitudinally and average intensity was sampled at each time point.
Results
Average non-normalized signal intensity over an ROI was measured across post stem cell engraftment day 0 (left), 7, (center), 45 (right).
Conclusions
MEMRI (left) and PET (center) were fused (right).
Funding
AZE Technology, Inc. Stanford University.
Authors’ Affiliations
Copyright
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. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.