title: CT-guided interventions using a free-hand, optical tracking system: initial clinical experience.
abstract: OBJECTIVE
  The present study was designed to evaluate the geometrical accuracy and clinical applicability of a new, free-hand, CT-guided, optical navigation system.
  
  
  METHODS
  Fifteen procedures in 14 consecutive patients were retrospectively analyzed. The navigation system was applied for interventional procedures on small target lesions, in cases with long needle paths, narrow access windows, or when an out-of-plane access was expected. Mean lesion volume was 27.9 ml, and mean distance to target measured was 107.5 mm. Eleven of 15 needle trajectories were planned as out-of-plane approaches regarding the axial CT plane.
  
  
  RESULTS
  Ninety-one percent of the biopsies were diagnostic. All therapeutic interventions were technically successful. Targeting precision was high with a mean distance of the needle tip from planned target of 1.98 mm. Mean intervention time was 1:12 h. A statistically significant correlation between angular needle deviation and intervention time (p = 0.007), respiratory movement of the target (p = 0.008), and body mass index (p = 0.02) was detected. None of the evaluated parameters correlated significantly with the distance from the needle tip to the planned target.
  
  
  CONCLUSIONS
  The application of a navigation system for complex CT-guided procedures provided safe and effective targeting within a reasonable intervention time in our series.
authors.affiliation: Department of Radiology and Nuclear Medicine, University Hospital Basel, 4031, Basel, Switzerland. TSchubert@uhbs.ch
authors.forename: Tilman
authors.initials: T
authors.lastname: Schubert
authors.forename: Augustinus L
authors.initials: AL
authors.lastname: Jacob
authors.forename: Michele
authors.initials: M
authors.lastname: Pansini
authors.forename: David
authors.initials: D
authors.lastname: Liu
authors.forename: Andreas
authors.initials: A
authors.lastname: Gutzeit
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle / Q000379:methods; D016022:Case-Control Studies; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D006225:Hand; D006801:Humans; D061705:Image-Guided Biopsy / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D055096:Optical Devices; D015641:Radiography, Interventional; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*