Evaluation of an electromagnetic virtual target system (CT-Guide) for interventional CT-guided procedures

Purpose: Evaluation of the accuracy of a new electromagnetic target system for interventional CT-guided procedures with virtual navigation in a previo usly acquired helical CT. Material and Methods: The new target system CT-Gu ide 1010 (Ultraguide, Tirat Hacarmel, Israel) for CT-guided interventions w as adapted to the video signal of the Somatom Plus 4 and Volume Zoom (Sieme ns, Erlangen, Germany). A helical CT-dataset including skin-based sensor cu bes was transferred to the integrated navigation system inside the scanner room. 50 image-guided interventions and biopsies were performed outside the gantry using virtual navigation to reach the lesion. The accuracy of the p rocedures was evaluated using documentation of the needle tip with CT-fluor oscopy, results of histology, and follow-up. Resuits: The deviation between planned and documented needle tip was 2.2 +/-2.1 mm in 50 procedures. Time between the end of planning-CT and needle positioning using the system was 13 minutes. There were no complications due to the use of the system. Conc lusion: The CT-Guide allows for virtual real-time navigation with high accu racy. Advantages are the free needle angulation without gantry tilt, use of optimal CT perfusion phase for virtual navigation, and reduction of radiat ion exposure to the patient and interventionalist.