title: Navi-ball: a new guidance device for CT-directed punctures.
abstract: OBJECTIVE
  A new navigation system (Navi-Ball) for computed tomography (CT)-guided punctures was tested clinically.
  
  
  METHODS
  The device consists of a transparent hemisphere with an angular scale. The hemisphere is fluid filled and contains a bubble indicating the angulation. The system works as a circular spirit level. Adapted to the handle of the needle, it allows needle adjustment according to the planned puncture path on the CT image. The system was tested in 36 patients who had 40 procedures. The needle deviation (in relation to the planned course of the needle) was measured in two rectangular planes.
  
  
  RESULTS
  Without requiring preparation time, the guidance system allowed rapid and easy performance of the puncture. First-time needle placement in a double-angulated approach led to a deviation of the needle from the planned path ranging from 0.2 degrees to 4.6 degrees (mean 2.1 degrees, SD 1.4 degrees ) in the axial plane and from 0.4 degrees to 4.0 degrees (mean 2.3 degrees, SD 1.2 degrees).
  
  
  CONCLUSIONS
  This "low-tech" system offers easy to use guidance by a single operator and provides for adequate accuracy of first-time needle placement.
authors.affiliation: Department of Diagnostic Radiology, University of Technology, Aachen, Germany. meyer@rad.rwth-aachen.de
authors.forename: J M
authors.initials: JM
authors.lastname: Meyer
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: G
authors.initials: G
authors.lastname: Krombach
authors.forename: J E
authors.initials: JE
authors.lastname: Wildberger
authors.forename: J
authors.initials: J
authors.lastname: Pfeffer
authors.forename: R W
authors.initials: RW
authors.lastname: Günther
mesh_terms: D004867:Equipment Design; D006801:Humans; D011677:Punctures / Q000295:instrumentation* / Q000379:methods*; D014057:Tomography, X-Ray Computed