title: Recovery of respiratory motion and deformation of the liver using laparoscopic freehand 3D ultrasound system.
abstract: The present paper describes a method for intraoperative recovery of respiratory motion and deformation of the liver by using a laparoscopic freehand 3D ultrasound (US) system. The proposed method can extend 3D US data of the liver to 4D by acquiring additional several sequences of time-varying 2D US images during a couple of respiration cycles. 2D US images are acquired on several sagittal image planes and their time-varying 3D positions and orientations are measured using a miniature magnetic 3D position sensor attached to a laparoscopic US (LUS) probe. During the acquisition, the LUS probe is assumed to move together with hepatic surface. Respiratory phases and in-plane 2D deformation fields are estimated from time-varying 2D US images, and then time-varying 3D deformation fields on sagittal image planes are obtained by combining 3D positions and orientations of the image planes. Time-varying 3D deformation field of the volume, that is, 4D deformation field, is obtained by interpolating the 3D deformation fields estimated on several planes. In vivo experiments using a pig liver showed that the proposed method could perform accurate estimation of respiratory cycle and in-plane 2D deformation fields. Furthermore, evaluation for the effects of sagittal plane interval indicated that 4D deformation fields could be stably recovered.
authors.affiliation: Division of Image Analysis, Osaka University Graduate School of Medicine, Japan. nakamoto@image.med.osaka-u.ac.jp
authors.forename: Masahiko
authors.initials: M
authors.lastname: Nakamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hirayama
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Sato
authors.forename: Kozo
authors.initials: K
authors.lastname: Konishi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kakeji
authors.forename: Makoto
authors.initials: M
authors.lastname: Hashizume
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tamura
mesh_terms: D000818:Animals; D003201:Computers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D010535:Laparoscopy / Q000379:methods*; D008099:Liver / Q000473:pathology*; D015233:Models, Statistical; D009068:Movement; D012119:Respiration; D013552:Swine; D013997:Time Factors; D014465:Ultrasonics; D014463:Ultrasonography / Q000379:methods*