title: Respiratory motion control for stereotactic and robotic liver interventions.
abstract: BACKGROUND
  Control of respiratory motion is an essential prerequisite for stereotactic computer-assisted and robotic interventions in the liver.
  
  
  METHODS
  The respiratory motion control error (RMCE) of temporary disconnections of the endotracheal tube (ETT) in anaesthetized patients has been evaluated during computer tomography (CT)-guided liver punctures. Two arterial and portal phase contrast-enhanced planning CTs were obtained during one ETT disconnection. After liver puncture, a native control CT was performed during a second ETT disconnection. By image fusion, the Euclidean errors of corresponding external and internal targets were calculated as baseline measures. RMCE was obtained by subtracting the Euclidean error during one ETT disconnection from the Euclidean error during two ETT disconnections.
  
  
  RESULTS
  In 26 patients, the overall mean RMCE showed 1.98 +/- 0.93 (range 0.44-4.02) mm for external targets and 1.41 +/- 0.75 (range 0.46-3.18) mm for the internal targets, without significant difference in means (p = 0.558). No complications were noted.
  
  
  CONCLUSIONS
  Temporary ETT disconnections are safe and may control respiratory motion for liver interventions within 4 mm.
authors.affiliation: Department of Microinvasive Therapy, Department of Radiology, Medical University of Innsbruck, Austria.
authors.forename: Gerlig
authors.initials: G
authors.lastname: Widmann
authors.forename: Peter
authors.initials: P
authors.lastname: Schullian
authors.forename: Marion
authors.initials: M
authors.lastname: Haidu
authors.forename: Franz J
authors.initials: FJ
authors.lastname: Wiedermann
authors.forename: Reto
authors.initials: R
authors.lastname: Bale
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000628:therapy*; D006801:Humans; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional / Q000379:methods; D007442:Intubation, Intratracheal; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009068:Movement; D056888:Patient Positioning; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D012143:Respiratory Physiological Phenomena; D012371:Robotics / Q000379:methods*; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography