title: Modeling and predicting tissue movement and deformation for high intensity focused ultrasound therapy.
abstract: OBJECTIVE
  In ultrasound-guided High Intensity Focused Ultrasound (HIFU) therapy, the target tissue (such as a tumor) often moves and/or deforms in response to an external force. This problem creates difficulties in treating patients and can lead to the destruction of normal tissue. In order to solve this problem, we present a novel method to model and predict the movement and deformation of the target tissue during ultrasound-guided HIFU therapy.
  
  
  METHODS
  Our method computationally predicts the position of the target tissue under external force. This prediction allows appropriate adjustments in the focal region during the application of HIFU so that the treatment head is kept aligned with the diseased tissue through the course of therapy. To accomplish this goal, we utilize the cow tissue as the experimental target tissue to collect spatial sequences of ultrasound images using the HIFU equipment. A Geodesic Localized Chan-Vese (GLCV) model is developed to segment the target tissue images. A 3D target tissue model is built based on the segmented results. A versatile particle framework is constructed based on Smoothed Particle Hydrodynamics (SPH) to model the movement and deformation of the target tissue. Further, an iterative parameter estimation algorithm is utilized to determine the essential parameters of the versatile particle framework. Finally, the versatile particle framework with the determined parameters is used to estimate the movement and deformation of the target tissue.
  
  
  RESULTS
  To validate our method, we compare the predicted contours with the ground truth contours. We found that the lowest, highest and average Dice Similarity Coefficient (DSC) values between predicted and ground truth contours were, respectively, 0.9615, 0.9770 and 0.9697.
  
  
  CONCLUSIONS
  Our experimental result indicates that the proposed method can effectively predict the dynamic contours of the moving and deforming tissue during ultrasound-guided HIFU therapy.
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Liao
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Qianfeng
authors.initials: Q
authors.lastname: Lai
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Jiaxiang
authors.initials: J
authors.lastname: Guo
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Sijiao
authors.initials: S
authors.lastname: Yu
authors.affiliation: School of Computer, Wuhan University, Wuhan, Hubei, China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Tong
authors.affiliation: Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Weixin
authors.initials: W
authors.lastname: Si
authors.affiliation: School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Mingui
authors.initials: M
authors.lastname: Sun
mesh_terms: D000465:Algorithms; D000818:Animals; D002417:Cattle; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008962:Models, Theoretical; D009068:Movement; D009928:Organ Specificity; D015203:Reproducibility of Results