Young's modulus reconstruction for radio-frequency ablation electrode-induced displacement fields: a feasibility study.
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.
Jiang
Jingfeng
J
Medical Physics Department, University of Wisconsin,Madison, WI 53705, USA. jjiang2@wisc.edu
Varghese
Tomy
T
Brace
Christopher L
CL
Madsen
Ernest L
EL
Hall
Timothy J
TJ
Bharat
Shyam
S
Hobson
Maritza A
MA
Zagzebski
James A
JA
Lee
Fred T
FT
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