title: 3D ultrasound registration-based visual servoing for neurosurgical navigation.
abstract: OBJECTIVE
  We present a fully image-based visual servoing framework for neurosurgical navigation and needle guidance. The proposed servo-control scheme allows for compensation of target anatomy movements, maintaining high navigational accuracy over time, and automatic needle guide alignment for accurate manual insertions.
  
  
  METHODS
  Our system comprises a motorized 3D ultrasound (US) transducer mounted on a robotic arm and equipped with a needle guide. It continuously registers US sweeps in real time with a pre-interventional plan based on CT or MR images and annotations. While a visual control law maintains anatomy visibility and alignment of the needle guide, a force controller is employed for acoustic coupling and tissue pressure. We validate the servoing capabilities of our method on a geometric gel phantom and real human anatomy, and the needle targeting accuracy using CT images on a lumbar spine gel phantom under neurosurgery conditions.
  
  
  RESULTS
  Despite the varying resolution of the acquired 3D sweeps, we achieved direction-independent positioning errors of [Formula: see text] mm and [Formula: see text], respectively. Our method is capable of compensating movements of around 25 mm/s and works reliably on human anatomy with errors of [Formula: see text] mm. In all four manual insertions by an expert surgeon, a needle could be successfully inserted into the facet joint, with an estimated targeting accuracy of [Formula: see text] mm, superior to the gold standard.
  
  
  CONCLUSIONS
  The experiments demonstrated the feasibility of robotic ultrasound-based navigation and needle guidance for neurosurgical applications such as lumbar spine injections.
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany. oliver.zettinig@tum.de.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA. oliver.zettinig@tum.de.
authors.forename: Oliver
authors.identifier: http://orcid.org/0000-0001-7344-3564
authors.initials: O
authors.lastname: Zettinig
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Frisch
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Virga
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Esposito
authors.affiliation: Neurochirurgische Klinik und Poliklinik, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, München, Germany.|Department of Orthopedic Surgery, Medical University Vienna, General Hospital, Vienna, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Rienmüller
authors.affiliation: Neurochirurgische Klinik und Poliklinik, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, München, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
authors.forename: Christoph
authors.initials: C
authors.lastname: Hennersperger
authors.affiliation: Neurochirurgische Klinik und Poliklinik, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675, München, Germany.
authors.forename: Yu-Mi
authors.initials: YM
authors.lastname: Ryang
authors.affiliation: Computer Aided Medical Procedures, Technische Universität München, Boltzmannstr. 3, 85748, Garching, Germany.|Computer Aided Medical Procedures, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD, 21218, USA.
authors.forename: Nassir
authors.initials: N
authors.lastname: Navab
mesh_terms: D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D009339:Needles; D038361:Neuronavigation / Q000379:methods*; D019047:Phantoms, Imaging; D012371:Robotics; D014463:Ultrasonography / Q000379:methods*
keywords: 3D Ultrasound; Needle insertion; Neurosurgical navigation; Registration-based visual servoing