PMID- 36819241 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20230224 IS - 2223-4292 (Print) IS - 2223-4306 (Electronic) IS - 2223-4306 (Linking) VI - 13 IP - 2 DP - 2023 Feb 1 TI - Low-dose spectral reconstruction with global, local, and nonlocal priors based on subspace decomposition. PG - 889-911 LID - 10.21037/qims-22-647 [doi] AB - BACKGROUND: Multienergy computed tomography (MECT) is a promising imaging modality for material decomposition, lesion detection, and other clinical applications. However, there is an urgent need to design efficient and accurate algorithms to solve the inverse problems related to spectral reconstruction and improve image quality, especially under low-dose and incomplete datasets. The key issue for MECT reconstruction is how to efficiently describe the interchannel and intrachannel priors in multichannel images. METHODS: In this model, in order to correlate the similarities of interchannel images and regularize the multichannel images, the global, local, and nonlocal priors are jointly integrated into the low-dose MECT reconstruction model. First, the subspace decomposition method first employs the global low-rankness to map the original MECT images to the low-dimensional eigenimages. Then, nonlocal self-similarity of the eigenimages is cascaded into the optimization model. Additionally, the L0 quasi-norm on gradient images is incorporated into the proposed method to further enhance the local sparsity of intrachannel images. The alternating direction method is applied to solve the optimization model in an iterative scheme. RESULTS: Simulation, preclinical, and real datasets were applied to validate the effectiveness of the proposed method. From the simulation dataset, the new method was found to reduce the root-mean-square error (RMSE) by 42.31% compared with the latest research fourth-order nonlocal tensor decomposition MECT reconstruction (FONT-SIR) method under 160 projection views. The calculation time of an iteration for the proposed method was 23.07% of the FONT-SIR method. The results of material decomposition in real mouse data further confirmed the accuracy of the proposed method for different materials. CONCLUSIONS: We developed a method in which the global, local, and nonlocal priors are jointly used to develop the reconstruction model for low-dose MECT, where the global low-rankness and nonlocal prior are cascaded by subspace decomposition and block-matching, and the L0 sparsity is applied to express the local prior. The results of the experiments demonstrate that the proposed method based on subspace improves computational efficiency and has advantages in noise suppression and structure preservation over competing algorithms. CI - 2023 Quantitative Imaging in Medicine and Surgery. All rights reserved. FAU - Yu, Xiaohuan AU - Yu X AD - Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, China. FAU - Cai, Ailong AU - Cai A AD - Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, China. FAU - Li, Lei AU - Li L AD - Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, China. FAU - Jiao, Zhiyong AU - Jiao Z AD - Beijing Science and Technology Information Research Center, Beijing, China. FAU - Yan, Bin AU - Yan B AD - Henan Key Laboratory of Imaging and Intelligent Processing, PLA Strategic Support Force Information Engineering University, Zhengzhou, China. LA - eng PT - Journal Article DEP - 20230105 PL - China TA - Quant Imaging Med Surg JT - Quantitative imaging in medicine and surgery JID - 101577942 PMC - PMC9929412 OTO - NOTNLM OT - Multienergy computed tomography (MECT) OT - global priors OT - image reconstruction OT - local and nonlocal priors OT - subspace decomposition COIS- Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-22-647/coif). The authors have no conflicts of interest to declare. EDAT- 2023/02/24 06:00 MHDA- 2023/02/24 06:01 PMCR- 2023/02/01 CRDT- 2023/02/23 10:01 PHST- 2022/06/21 00:00 [received] PHST- 2022/12/02 00:00 [accepted] PHST- 2023/02/23 10:01 [entrez] PHST- 2023/02/24 06:00 [pubmed] PHST- 2023/02/24 06:01 [medline] PHST- 2023/02/01 00:00 [pmc-release] AID - qims-13-02-889 [pii] AID - 10.21037/qims-22-647 [doi] PST - ppublish SO - Quant Imaging Med Surg. 2023 Feb 1;13(2):889-911. doi: 10.21037/qims-22-647. Epub 2023 Jan 5.