In vivo imaging of atherosclerotic plaque growth in ApoE-/- Mice using
A. Walz-Flannigan, S.P. Mok, Y. Wang, K. L. Gabrielson, J. Fox , C. Foss, S. Nimmagadda, M. Seshadri, M. G. Pomper, and B.M.W. Tsui
Department of Radiology, Johns
In our study, we wished to ascertain the feasibility of using a small animal SPECT/CT system with Tc99m-HYNIC-Annexin-V to identify and follow atherosclerotic lesions in ApoE-/- mice.
Transgenic ApoE-/- mice were fed a high fat and cholesterol diet
starting from 5 weeks up to 41 weeks of age. During this time SPECT and CT
image data were acquired from each animal at 3 to 4 time points between 18 and
41 weeks using a Gamma Medica-Ideas FLEX MicroSPECT/CT imager. The SPECT imaging system is equipped
with dual modular cameras having 82x82 NaI
SPECT/CT images show an increased uptake of Tc99m-HYNIC-Annexin-V at areas consistent with the development of atherosclerotic lesions in ApoE-/- mice. We observed an increase in uptake and number of atherosclerotic lesions over multiple scans. In at least one case we were able to follow a single lesion over three time points between 20 and 27 weeks of age and observe a change in its overall size or uptake. Later time points also exhibited an overall increase in the uptake of Tc99m-HYNIC-Annexin-V in the heart muscle and other organs. The aorta, carotid and pulmonary arteries, excised between 38 and 41 weeks, showed extensive plaque development throughout. Autoradiography confirmed the uptake of Tc99m-HYNIC-Annexin-V in the plaques.
We are able to detect atherosclerotic plaques in ApoE-/- mice and monitor their uptake of Tc99m-HYNIC-Annexin-V with current SPECT imaging equipment and techniques. These measurements are being used as a guide in continuing studies to correlate images with specific physiological changes and to develop high resolution SPECT imaging systems with quantitative image reconstruction methods.
NIH grant # R01 EB1558.