Reconstruction for Limited-Projection Fluorescence Molecular Tomography Based on a Double-Mesh Strategy

Abstract

Limited-projection fluorescence molecular tomography (FMT) has short data acquisition time that allows fast resolving of the three-dimensional visualization of fluorophore within small animal in vivo. However, limited-projection FMT reconstruction suffers from severe ill-posedness because only limited projections are used for reconstruction. To alleviate the ill-posedness, a feasible region extraction strategy based on a double mesh is presented for limited-projection FMT. First, an initial result is rapidly recovered using a coarse discretization mesh. Then, the reconstructed fluorophore area in the initial result is selected as a feasible region to guide the reconstruction using a fine discretization mesh. Simulation experiments on a digital mouse and small animal experiment in vivo are performed to validate the proposed strategy. It demonstrates that the presented strategy provides a good distribution of fluorophore with limited projections of fluorescence measurements. Hence, it is suitable for reconstruction of limited-projection FMT.

Figure 1

The flow chart of the proposed reconstruction method based on a double-mesh strategy.

Figure 2

3D views of the reconstructed results with 3, 6, 9, and 12 projections, respectively.

Figure 3

The quantitative results with 3, 6, 9, and 12 projections. (a) CLE (mm), (b) nRMSE, (c) RE, (d) CNR, and (e) time cost (s).

Figure 4

Reconstruction results with a coarse mesh, the double-mesh strategy, and the fine mesh based on l ₁-norm regularization. (a, b, c) show the cross-sectional views (z = 15.9 mm) of the fluorophore, and the black circles denote the real position of fluorophore. (d, e, f) show the corresponding coronal view of the recovered tetrahedral element, and the sphere is the fluorophore.

Figure 5

CLE (a), nRMSE (b), RE (c), CNR (d), and time cost (e) of recovered results for three mesh levels.

Figure 6

The reconstructed results with coarse mesh (a, b, c), double mesh (d, e, f), and fine mesh (g, h, i), respectively.

Figure 7

Recovered results in 3D views with coarse mesh (a), double mesh (b), and fine mesh (c). The red cylinder is the glass tube and the blue region is recovered target.