title: Young's modulus reconstruction for radio-frequency ablation electrode-induced displacement fields: a feasibility study.
abstract: Radio-frequency (RF) ablation is a minimally invasive treatment for tumors in various abdominal organs. It is effective if good tumor localization and intraprocedural monitoring can be done. In this paper, we investigate the feasibility of using an ultrasound-based Young's modulus reconstruction algorithm to image an ablated region whose stiffness is elevated due to tissue coagulation. To obtain controllable tissue deformations for abdominal organs during and/or intermediately after the RF ablation, the proposed modulus imaging method is specifically designed for using tissue deformation fields induced by the RF electrode. We have developed a new scheme under which the reconstruction problem is simplified to a 2-D problem. Based on this scheme, an iterative Young's modulus reconstruction technique with edge-preserving regularization was developed to estimate the Young's modulus distribution. The method was tested in experiments using a tissue-mimicking phantom and on ex vivo bovine liver tissues. Our preliminary results suggest that high contrast modulus images can be successfully reconstructed. In both experiments, the geometries of the reconstructed modulus images of thermal ablation zones match well with the phantom design and the gross pathology image, respectively.
authors.affiliation: Medical Physics Department, University of Wisconsin,Madison, WI 53705, USA. jjiang2@wisc.edu
authors.forename: Jingfeng
authors.initials: J
authors.lastname: Jiang
authors.forename: Tomy
authors.initials: T
authors.lastname: Varghese
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
authors.forename: Ernest L
authors.initials: EL
authors.lastname: Madsen
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Hall
authors.forename: Shyam
authors.initials: S
authors.lastname: Bharat
authors.forename: Maritza A
authors.initials: MA
authors.lastname: Hobson
authors.forename: James A
authors.initials: JA
authors.lastname: Zagzebski
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D002417:Cattle; D055119:Elastic Modulus / Q000502:physiology*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D020342:Finite Element Analysis; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011846:Radio Waves