title: SonoWand, an ultrasound-based neuronavigation system.
abstract: OBJECTIVE
  We have integrated a neuronavigation system into an ultrasound scanner and developed a single-rack system that enables the surgeon to perform frameless and armless stereotactic neuronavigation using intraoperative three-dimensional ultrasound data as well as preoperative magnetic resonance or computed tomographic images. The purpose of this article is to describe our two-rack prototype and present the results of our work on image quality enhancement.
  
  
  METHODS
  The system consists of a high-end ultrasound scanner, a modest-cost computer, and an optical positioning/digitizer system. Special technical and clinical efforts have been made to achieve high image quality. A special interface between the ultrasound instrument and the navigation computer ensures rapid transfer of digital three-dimensional data with no loss of image quality.
  
  
  METHODS
  The positioning system tracks the position and orientation of the patient, the ultrasound probe, the pointer, and various surgical instruments. This makes it possible to update the three-dimensional map during surgery and navigate by ultrasound data in a similar manner as with magnetic resonance data.
  
  
  METHODS
  The two-rack prototype has been used for clinical testing since November 1997 at the University Hospital in Trondheim.
  
  
  RESULTS
  The image quality improvements have enabled us, in most cases, to extract information from ultrasound with clinical value similar to that of preoperative magnetic resonance imaging. The overall clinical accuracy of the ultrasound-based navigation system is expected to be comparable to or better than that of a magnetic resonance imaging-based system.
  
  
  CONCLUSIONS
  The SonoWand system enables neuronavigation through direct use of intraoperative three-dimensional ultrasound. Further research will be necessary to explore the potential clinical value and the limitations of this technology.
authors: SINTEF Unimed, Trondheim, Norway. aage.gronningsaeter@mison.no
authors: A
authors: A
authors: Gronningsaeter
authors: A
authors: A
authors: Kleven
authors: S
authors: S
authors: Ommedal
authors: T E
authors: TE
authors: Aarseth
authors: T
authors: T
authors: Lie
authors: F
authors: F
authors: Lindseth
authors: T
authors: T
authors: Langø
authors: G
authors: G
authors: Unsgård
mesh_terms: D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D019635:Neurosurgical Procedures / Q000295:instrumentation*; D013238:Stereotaxic Techniques / Q000295:instrumentation*; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods*