Bioluminescence tomography with structural information estimated via statistical mouse atlas registration

Bin Zhang,Wanzhou Yin,Xu Cao,Hao Liu,Hongkai Wang

doi:10.1364/boe.9.003544

Abstract

Due to an ill-posed and underestimated characteristic of bioluminescence tomography (BLT) reconstruction, a priori anatomical information obtained from computed tomography (CT) or magnetic resonance imaging (MRI), is usually incorporated to improve the reconstruction accuracy. The organs need to be segmented, which is time-consuming and challenging, especially for the low-contrast CT images. In this paper, we present a BLT reconstruction method based on a statistical mouse atlas to improve the efficiency of heterogeneous model generation and the accuracy of target localization. The low-contrast CT image of the mouse was first registered to the statistical mouse atlas model with the constraints of mouse surface and high-contrast organs (bone and lung). Then the other organs, such as the liver and kidney, were determined automatically through the statistical mouse atlas model. The estimated organs were then discretized into tetrahedral meshes for BLT reconstruction. The linearized Bregman method was used to solve the sparse inverse problem of BLT by minimizing the regularization function (L1 norm plus L2 norm with smooth factor). Both numerical simulations and in vivo experiments were conducted, and the results demonstrate that even though the localization of the estimated organs may not be exactly accurate, the proposed method is feasible to reconstruct the bioluminescent source effectively and accurately with the estimated organs. This method would greatly benefit the bioluminescent light source localization for hybrid BLT/CT systems.

Highlights

Bioluminescence tomography (BLT), as applied in preclinical molecular imaging, has attracted widespread attentions over biological and medical researches
BLT is capable of revealing the localization of the bioluminescence source inside a small animal from the bioluminescence images (BLIs) which are non-invasively detected on the surface
The results demonstrate that the statistical mouse atlas is feasible for BLT reconstruction and can provide acceptable accuracy for localizing bioluminescent sources

Summary

Introduction

Bioluminescence tomography (BLT), as applied in preclinical molecular imaging, has attracted widespread attentions over biological and medical researches. With the coding genes for bioluminescent protein, it provides a specific tool to study the biological processes in vivo at the cellular and molecular levels [1,2,3]. It has extensive applications in preclinical studies for cancer research and drug development. The organ segmentation is time-consuming and challenging, especially for the low-contrast CT images. For non-contrast enhanced CT images, segmentation of soft tissue organs is difficult. The automatic segmentation methods are not feasible for segmentation of the soft tissue organs, while manual segmentation is usually time-consuming and inevitably prone to bias and error

Methods

Findings

Discussion

Conclusion