NIR-II/NIR-I Fluorescence Molecular Tomography of Heterogeneous Mice Based on Gaussian Weighted Neighborhood Fused Lasso Method.

Meishan Cai,Zeyu Zhang,Jie Tian,Xiaojing Shi,Zhenhua Hu

doi:10.1109/tmi.2020.2964853

Abstract

Fluorescence molecular tomography (FMT), which can visualize the distribution of fluorescence biomarkers, has become a novel three-dimensional noninvasive imaging technique for in vivo studies such as tumor detection and lymph node location. However, it remains a challenging problem to achieve satisfactory reconstruction performance of conventional FMT in the first near-infrared window (NIR-I, 700-900nm) because of the severe scattering of NIR-I light. In this study, a promising FMT method for heterogeneous mice was proposed to improve the reconstruction accuracy using the second near-infrared window (NIR-II, 1000-1700nm), where the light scattering significantly reduced compared with NIR-I. The optical properties of NIR-II were analyzed to construct the forward model for NIR-II FMT. Furthermore, to raise the accuracy of solution of the inverse problem, we proposed a novel Gaussian weighted neighborhood fused Lasso (GWNFL) method. Numerical simulation was performed to demonstrate the outperformance of GWNFL compared with other algorithms. Besides, a novel NIR-II/NIR-I dual-modality FMT system was developed to contrast the in vivo reconstruction performance between NIR-II FMT and NIR-I FMT. To compare the reconstruction performance of NIR-II FMT with traditional NIR-I FMT, numerical simulations and in vivo experiments were conducted. Both the simulation and in vivo results showed that NIR-II FMT outperformed NIR-I FMT in terms of location accuracy and spatial overlap index. It is believed that this study could promote the development and biomedical application of NIR-II FMT in the future.

Highlights

F LUORESCENCE molecular imaging (FMI) in the near-infrared (NIR) region has been widely used in preclinical research and clinical practice for its high spatial and temporal resolutions [1]–[3]
Because of the strong scattering and absorption effect of NIR-I light, the reconstruction performance of the traditional NIR-I Fluorescence molecular tomography (FMT) remains unsatisfactory for its high ill-posedness
With the development of novel imaging dyes and charge coupled devices (CCDs), considerable research attention has been paid to FMI in the NIR-II region for its lower scattering and absorption caused by the longer wavelength

Summary

Introduction

F LUORESCENCE molecular imaging (FMI) in the near-infrared (NIR) region has been widely used in preclinical research and clinical practice for its high spatial and temporal resolutions [1]–[3]. Based on the optical signal excited from the fluorescent dyes, FMI has become an effective and significant technique for tumor detection, image-guided surgery, lymph node visualization, and other biomedical applications [4], [5]. Compared with other optical molecular imaging modalities, such as bioluminescence imaging (BLI) [6] and Cherenkov luminescence imaging (CLI) [7], FMI has a better prospect for clinical translation because of high penetration depth, operation convenience, nonradiation, and low cost. NIR-I FMI can only achieve a planar image, which is incapable of determining the exact location of tumors in vivo because of the lack of depth information [8]. Based on the combination of the NIR-I FMI information and the anatomical information such

Methods

Results

Conclusion