Bernhard Meyer MD, Presenter: Research Consultant, Mercury Computer Systems, Inc Stockholder, Mercury Computer Systems, Inc Research grant, Siemens AG Research grant, Bracco Group Research grant, Bayer AG

Olaf Peter, Abstract Co-Author: Nothing to Disclose

Karl-Juergen Wolf MD, Abstract Co-Author: Nothing to Disclose

Frank K. Wacker MD, Abstract Co-Author: Research grant, Siemens AG Advisory Board, Siemens AG Research grant, Mercury Computer Systems, Inc

Markus Nagel PhD, Abstract Co-Author: Employee, CAS innovations AG

To evaluate the usability and accuracy of an electromagnetic field-based navigation system for C-Arm CT-guided abscess drainage.

12 patients with known abscesses were included in the study. Images were acquired using a C-Arm CT (=CACT, DynaCT®, Axiom Artis dBA, Siemens). An electromagnetic navigation system(=ND, CAPPA IRAD EMT, cas innovations), consisting of a workstation, a field generator, and a trackable puncture needle was used for puncture. After defining a target point in the abscess, the needle position was electromagnetically tracked and interactively visualized in the 3D-CACT dataset during puncture. After reaching the abscess, the needle position was verified on CACT images prior to drainage catheter insertion. The puncture duration was recorded and errors were calculated (user error=distance between target and visualized needle tip position; system error=distance between visualized and real needle tip position).

The interactive needle visualisation using real-time MPR of the CACT dataset facilitated safe and reliable puncture guidance, leading to an average skin-to-target time of 65 seconds (range,35–98 seconds). The targeted puncture was successful in all cases with a mean user error of 6 mm (range, 3-10 mm) and a mean system error of 5 mm (range, 3-6 mm). The total puncture time ranged from 3-10min, including trajectory planning. The average scan-to-scan time (from achieving the preprocedural CACT to the control CACT) was 24 minutes.

In this first clinical trial on abscess drainage procedures, electromagnetic tracking in combination with C-arm CT images provided safe and reliable real-time puncture guidance leading to a correct needle placement in all patients.

Electromagnetic field-based needle guidance facilitates the needle placement by online monitoring of the real needle tip position and enables double angulated punctures based on C-Arm CT images.

Meyer, B, Peter, O, Wolf, K, Wacker, F, Nagel, M, Electromagnetic Field-based Navigation-guided Abscess Drainage in C-Arm CT.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6014879.html