Title
Image-domain multi-material decomposition for dual-energy CT with non-convex sparsity regularization.
Abstract
Dual energy CT (DECT) has the potential to decompose tissues into different materials. However, the classic direct inversion (DI) method for multi-material decomposition (MMD) cannot accurately separate more than two basis materials due to the ill W-posed problem and amplified image noise. We proposed a novel integrated MMD method that addresses the piecewise smoothness and intrinsic sparsity property of the decomposition image. The proposed MMD was formulated as an optimization problem including a quadratic data fidelity term, an isotropic total variation term that encourages image smoothness, and a non-convex penalty function that promotes decomposition image sparseness. The mass and volume conservation rule were formulated as the probability simplex constraint. An accelerated primal-dual splitting approach with line search was applied to solve the optimization problem. The proposed method with different penalty functions was compared against DI on a digital phantom, a Catphano600 phantom, a Quantitative Imaging phantom, and a pelvis patient. The proposed framework distinctly separated the CT image into up to 12 basis materials plus air with high decomposition accuracy. The cross-talks between two different materials are substantially reduced as shown by the decreased non diagonal elements of the Normalized Cross Correlation (NCC) matrix. The mean square error of the measured electron densities was reduced by 72.6%. Across all datasets, the proposed method improved the average Volume Fraction (VF) accuracy from 63.9% to 99.8% and increased the diagonality of the NCC matrix from 0.73 to 0.96. Compared with DI, the proposed MMD framework improved decomposition accuracy and material separation.
Year
DOI
Venue
2019
10.1117/12.2508037
Proceedings of SPIE
Keywords
DocType
Volume
Dual energy CT (DECT),multi-material decomposition (MMD),primal-dual splitting,non-convex optimization
Conference
10949
ISSN
Citations 
PageRank 
0277-786X
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Qihui Lyu101.01
Daniel O'Connor200.34
Niu, T.322.39
Ke Sheng400.34