title: A miniature accelerometer-based guidance device for percutaneous computed tomography-guided punctures.
abstract: OBJECTIVE
  Percutaneous punctures are often performed under computed tomography (CT) guidance using a freehand method. Especially in challenging cases, initial accuracy of the needle placement is highly dependent on the radiologist's experience. Thus, a miniature lightweight guidance device was developed which is capable of assisting a radiologist during the needle placement process.
  
  
  METHODS
  The device utilizes an accelerometer to measure the needle's tilt by calculating a set of orientation angles. This set can be matched with the coordinate system of the CT imaging software during a simple alignment process. After that, the needle's orientation can be expressed in terms of projected angles in the axial and sagittal planes. The accuracy of the device was evaluated in a phantom study, and initial clinical trials were carried out performing facet joint punctures in a swine cadaver.
  
  
  RESULTS
  The sensor was embedded in a cube with dimensions of [Formula: see text] and a total weight of about 11 g which can be attached to the puncture needle at its rear end or handgrip. A graphical user interface (GUÌ) has been created offering visual real-time orientation guidance. Results of the phantom experiments showed differences between planned target and performed puncture angles of [Formula: see text] for in-plane and [Formula: see text] for out-of-plane punctures.
  
  
  CONCLUSIONS
  The results of the phantom and ex vivo study suggest that the device is useful to assist a radiologist in CT-guided percutaneous punctures and helps navigating the needle with high precision.
authors: Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Pauwelsstraße 30, 52074 , Aachen, Germany, Christoph.Wilkmann@rwth-aachen.de.
authors: Christoph
authors: C
authors: Wilkmann
authors: Nobutake
authors: N
authors: Ito
authors: Tobias
authors: T
authors: Penzkofer
authors: Peter
authors: P
authors: Isfort
authors: Hong-Sik
authors: HS
authors: Na
authors: Michael
authors: M
authors: Hennes
authors: Catherine
authors: C
authors: Disselhorst-Klug
authors: Andreas H
authors: AH
authors: Mahnken
authors: Christiane K
authors: CK
authors: Kuhl
authors: Philipp
authors: P
authors: Bruners
mesh_terms: D061725:Accelerometry; D000818:Animals; D006801:Humans; D011677:Punctures / Q000379:methods*; D015203:Reproducibility of Results; D012984:Software; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods*; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging*