A method of extracting structural priors from images of micro-CT for fluorescence molecular tomography reconstruction

The dual-modality systems combined fluorescence molecular tomography (FMT) and micro-computed tomography (micro-CT) can provide molecular and anatomical information of small animals simultaneously. Except for anatomic localization, micro-CT should also offer boundary of different organs as reconstruction priors for FMT, which is more challenging than acquisition of structural information. In this paper, we propose a framework to extract structural priors of a living mouse with micro-CT. The iodinated lipid emulsion contrast agent was adopted to enhance the contrast of the soft tissues of the mouse. Then organs in thorax and abdomen were segmented with different approaches depending on the characteristics of the organs. Bone, lung, heart, liver, spleen, and muscles were separately segmented. And the results were compared with that manually segmented. The Tanimoto coefficient and the relative volume difference of segmented slices were measured to be 91.28 ± 5.78 and 0.27 ± 3.15, respectively. In our simulation study of FMT reconstruction, the errors of measured position and concentration of the fluorophore with priors declined by 89.7% and 79.6% in thorax, as well as 80.8% and 78.3% in abdomen, respectively, compared with the results without priors. The proposed scheme will make FMT reconstruction much more reliable and practical in small animal study.