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Abstract #3963

Precise Co-Registration of SPECT and MRI for Small Animal Imaging Using a Common Animal Bed with External References:Visualization of Macrophage Distribution Within Inflammatory Lymph Nodes

Masayuki Yamaguchi1, Daisuke Suzuki1,2, Ryosuke Shimizu1,2, Ryutaro Nakagami1,3, Keisuke Tsuda1, Izumi Ogihara Umeda1, Yasuo Okuyama2, Kohki Yoshikawa2, Hirofumi Fujii1,4

1Functional Imaging Division, National Cancer Center Hospital East, Kashiwa, Chiba, Japan; 2Faculty of Health Sciences, Komazawa University, Setagaya, Tokyo, Japan; 3Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa, Tokyo, Japan; 4Institute for Bioinformatics Research and Development-Japan Science and Technology Agency, Chiyoda, Tokyo, Japan

We tested the SPECT-MRI fusion technique to visualize regional lymph nodes involved in subacute inflammation arising from the lymphatic basin using a mouse model. Two to three weeks after the administration of Freund complete adjuvant to the foot pad, 99mTc phytate high-resolution SPECT images of the hind limb were obtained using a small animal SPECT scanner equipped with 4 detectors with multi-pinhole collimators. These SPECT images were merged with MR images to provid precise anatomical information. SPECT-MRI fusion images showed swollen popliteal lymph nodes and the accumulation of 99mTc at the periphery, suggesting the inhomogeneous distribution of macrophages within the swollen lymph nodes.