title: Polarization image segmentation of radiofrequency ablated porcine myocardial tissue.
abstract: Optical polarimetry has previously imaged the spatial extent of a typical radiofrequency ablated (RFA) lesion in myocardial tissue, exhibiting significantly lower total depolarization at the necrotic core compared to healthy tissue, and intermediate values at the RFA rim region. Here, total depolarization in ablated myocardium was used to segment the total depolarization image into three (core, rim and healthy) zones. A local fuzzy thresholding algorithm was used for this multi-region segmentation, and then compared with a ground truth segmentation obtained from manual demarcation of RFA core and rim regions on the histopathology image. Quantitative comparison of the algorithm segmentation results was performed with evaluation metrics such as dice similarity coefficient (DSC = 0.78 ± 0.02 and 0.80 ± 0.02), sensitivity (Sn = 0.83 ± 0.10 and 0.91 ± 0.08), specificity (Sp = 0.76 ± 0.17 and 0.72 ± 0.17) and accuracy (Acc = 0.81 ± 0.09 and 0.71 ± 0.10) for RFA core and rim regions, respectively. This automatic segmentation of parametric depolarization images suggests a novel application of optical polarimetry, namely its use in objective RFA image quantification.
authors.affiliation: Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Science (PIEAS), Nilore, Islamabad, Pakistan.
authors.forename: Iftikhar
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Division of Biophysics and Bioimaging, Princess Margaret Cancer Centre, University Health Network, 610 University Avenue, Toronto, Ontario, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Gribble
authors.affiliation: Department of Computer and Information Sciences, Pakistan Institute of Engineering and Applied Science (PIEAS), Nilore, Islamabad, Pakistan.
authors.forename: Iqbal
authors.initials: I
authors.lastname: Murtza
authors.affiliation: Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Science (PIEAS), Nilore, Islamabad, Pakistan.
authors.forename: Masroor
authors.initials: M
authors.lastname: Ikram
authors.affiliation: Sunnybrook Research Institute, Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario, Canada.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Pop
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|Division of Biophysics and Bioimaging, Princess Margaret Cancer Centre, University Health Network, 610 University Avenue, Toronto, Ontario, Canada.|Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Vitkin
mesh_terms: D000465:Algorithms; D000818:Animals; D017115:Catheter Ablation; D017143:Fuzzy Logic; D006321:Heart / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D009206:Myocardium / Q000473:pathology*; D057109:Scanning Laser Polarimetry / Q000379:methods; D013552:Swine