title: Novel 3-D laparoscopic magnetic ultrasound image guidance for lesion targeting.
abstract: OBJECTIVE
  Accurate laparoscopic liver lesion targeting for biopsy or ablation depends on the ability to merge laparoscopic and ultrasound images with proprioceptive instrument positioning, a skill that can be acquired only through extensive experience. The aim of this study was to determine whether using magnetic positional tracking to provide three-dimensional, real-time guidance improves accuracy during laparoscopic needle placement.
  
  
  METHODS
  Magnetic sensors were embedded into a needle and laparoscopic ultrasound transducer. These sensors interrupted the magnetic fields produced by an electromagnetic field generator, allowing for real-time, 3-D guidance on a stereoscopic monitor. Targets measuring 5 mm were embedded 3-5 cm deep in agar and placed inside a laparoscopic trainer box. Two novices (a college student and an intern) and two experts (hepatopancreatobiliary surgeons) targeted the lesions out of the ultrasound plane using either traditional or 3-D guidance.
  
  
  RESULTS
  Each subject targeted 22 lesions, 11 with traditional and 11 with the novel guidance (n= 88). Hit rates of 32% (14/44) and 100% (44/44) were observed with the traditional approach and the 3-D magnetic guidance approach, respectively. The novices were essentially unable to hit the targets using the traditional approach, but did not miss using the novel system. The hit rate of experts improved from 59% (13/22) to 100% (22/22) (P < 0.0001).
  
  
  CONCLUSIONS
  The novel magnetic 3-D laparoscopic ultrasound guidance results in perfect targeting of 5-mm lesions, even by surgical novices.
authors.affiliation: Division of Hepatobiliary Surgery, Department of General Surgery, Carolinas Medical Center, Charlotte, NC 28204, USA. david.sindram@carolinashealthcare.org
authors.forename: David
authors.initials: D
authors.lastname: Sindram
authors.forename: Iain H
authors.initials: IH
authors.lastname: McKillop
authors.forename: John B
authors.initials: JB
authors.lastname: Martinie
authors.forename: David A
authors.initials: DA
authors.lastname: Iannitti
mesh_terms: D001707:Biopsy, Needle; D002983:Clinical Competence; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D010535:Laparoscopy / Q000295:instrumentation / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008280:Magnetics / Q000295:instrumentation; D009048:Motor Skills; D009339:Needles; D019047:Phantoms, Imaging; D025321:Surgery, Computer-Assisted / Q000295:instrumentation; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation