European Radiology

, Volume 19, Issue 4, pp 990–994 | Cite as

Electromagnetic tracking for CT-guided spine interventions: phantom, ex-vivo and in-vivo results

  • Philipp BrunersEmail author
  • Tobias Penzkofer
  • Markus Nagel
  • Robert Elfring
  • Nina Gronloh
  • Thomas Schmitz-Rode
  • Rolf W. Günther
  • Andreas H. Mahnken


An electromagnetic-based tracking and navigation system was evaluated for interventional radiology. The electromagnetic tracking system (CAPPA IRAD EMT, CASinnovations, Erlangen, Germany) was used for real-time monitoring of punctures of the lumbar facet joints and intervertebral disks in a spine phantom, three pig cadavers and three anaesthesized pigs. Therefore, pre-interventional computed tomography (CT) datasets were transferred to the navigation system and puncture trajectories were planned. A coaxial needle was advanced along the trajectories while the position of the needle tip was monitored in real time. After puncture tracts were marked with pieces of wire another CT examination was performed and distances between wires and anatomical targets were measured. Performing punctures of the facet joints mean needle positioning errors were 0.4 ± 0.8 mm in the spine phantom, 2.8 ± 2.1 mm ex vivo and 3.0 ± 2.0 mm in vivo with mean length of the puncture tract of 54.0 ± 10.4 mm (phantom), 51.6 ± 12.6 mm (ex vivo) and 50.9 ± 17.6 mm (in vivo). At first attempt, intervertebral discs were successfully punctured in 15/15 in the phantom study, in 12/15 in the ex-vivo study and 14/15 in the in-vivo study, respectively. Immobilization of the patient and optimal positioning of the field generator are essential to achieve a high accuracy of needle placement in a clinical CT setting.


Interventional radiology Computed tomography Navigation 



This work has been funded in part by the German Ministry for Education and Research (BMBF) in the framework of the OrthoMIT project under grant no. 01EQ0402.


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Copyright information

© European Society of Radiology 2008

Authors and Affiliations

  • Philipp Bruners
    • 1
    • 2
    Email author
  • Tobias Penzkofer
    • 1
    • 2
  • Markus Nagel
    • 3
  • Robert Elfring
    • 1
  • Nina Gronloh
    • 4
  • Thomas Schmitz-Rode
    • 1
  • Rolf W. Günther
    • 2
  • Andreas H. Mahnken
    • 2
  1. 1.Helmholtz-Institute for Biomedical EngineeringRWTH Aachen UniversityAachenGermany
  2. 2.Department of Diagnostic RadiologyUniversity Hospital, RWTH Aachen UniversityAachenGermany
  3. 3.CAS innovations AGErlangenGermany
  4. 4.Institute for Veterinary MedicineUniversity Hospital, RWTH Aachen UniversityAachenGermany

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