title: Fast temperature estimation from undersampled k-space with fully-sampled center for MR guided microwave ablation.
abstract: This study aims to accelerate MR temperature imaging using the proton resonance frequency (PRF) shift method for real time temperature monitoring during thermal ablation.
  
  
  
  The proposed method estimates temperature changes from undersampled k-space with a fully sampled center. This proposed algorithm is based on the hybrid multi-baseline and referenceless treatment image model and can be seen as an extension of the conventional k-space-based hybrid thermometry. The parameters of hybrid model are acquired by utilizing information from low resolution images which are obtained from fully-sampled centers of k-space. Registration is used to correct temperature errors due to the displacement of the subject. Phantom heating simulations, motion simulations, phantom heating and in-vivo experiments were performed to investigate the efficiency of the proposed method. SPIRiT and the conventional k-space estimation reconstruction thermometry were implemented for comparison using the same sampling pattern.
  
  
  
  The phantom heating simulations showed that the proposed method results in lower RMSEs than the conventional k-space hybrid thermometry and SPIRiT at various reduction factors tested. The motion simulations indicated the robustness of the proposed method to displacement of the subject. Phantom heating experiment further demonstrated the ability of the method to reconstruct temperature maps with less computation time and higher accuracy (RMSEs lower than 0.4°C) at a net reduction factor of 3.5 in the presence of large noise caused by a microwave needle. In-vivo experiments validated the feasibility of the proposed method to estimate temperature changes from undersampled k-space (net reduction factor 4.3) in presence of respiratory motion and complicated anatomical structure, while reducing computation time as much as 10-fold compared with the conventional k-space method.
  
  
  
  The proposed method accelerates the PRF-shift MR thermometry and provides more accurate temperature maps in presence of motion with relatively short computation time, which may make real time imaging for MR-guided microwave ablation possible.
authors.affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors.forename: Fuyixue
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors.forename: Zijing
authors.initials: Z
authors.lastname: Dong
authors.affiliation: Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Department of Engineering Physics, Tsinghua University, Beijing, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China.
authors.forename: Bingyao
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China.
authors.forename: Jiafei
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, Beijing, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Wei
authors.affiliation: Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Department of Engineering Physics, Tsinghua University, Beijing, China.
authors.forename: Shi
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Particle and Radiation Imaging, Ministry of Education, Medical Physics and Engineering Institute, Department of Engineering Physics, Tsinghua University, Beijing, China. Electronic address: yingkui@mail.tsinghua.edu.cn.
authors.forename: Kui
authors.initials: K
authors.lastname: Ying
mesh_terms: D055011:Ablation Techniques; D000465:Algorithms; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging*; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008872:Microwaves; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D012016:Reference Values; D013696:Temperature; D062125:Thermometry / Q000379:methods*
keywords: Acceleration; Microwave ablation; Proton resonance frequency shift; Temperature imaging