Targeting accuracy of CT-guided stereotaxy for radiofrequency ablation of liver tumours

Abstract

The targeting accuracy during CT-guided stereotactic radiofrequency ablation (SRFA) of liver tumours was evaluated in a clinical study. Patients under general anaesthesia were immobilized using a vacuum cushion and respiratory motion control was based on temporary disconnections of the endotracheal tube. An optical-based navigation system was used for 3D trajectory planning and needle placement via a stereotactic aiming device. A control CT with the needles in place was fused with the planning CT for accuracy evaluation. Sub-analysis was performed for “location” (liver segments II – VIII), “approach” (intercostal or transabdominal), “properties” (clear parenchymal, subcapsular, subphrenic, fat, and subphrenic plus fat), and “path length”. In 20 patients with 35 liver lesions, a total of 145 needles were placed with mean (±SD) lateral errors of 3.6 ± 2.5 mm at the needle tip, angular errors of 1.3° ± 1.2°, and longitudinal errors at the needle tip of -7.4 ± 6.2 mm. No puncture-related complications were noted. No significant differences of angular errors between segments, approach and properties were recorded. Long paths correlated with smaller angular errors. CT-guided stereotaxy can be considered safe and provided precise multiple needle placement for SRFA of liver lesions at arbitrary trajectories in various segments and locations.

Key words::

• Stereotaxy
• interventional radiology
• radiofrequency ablation
• accuracy
• liver

Acknowledgements

The authors would like to express their sincere gratitude to the the radiation technicians Thomas Bob Lang, RT, Florian Schanda, RT, Julia Mahlknecht, RT, and Martin Knoflach, RT, from the Department of Microinvasive Therapy, Department of Radiology.

Disclosure: Prof. Bale is a (co)inventor of the BlueBAG vacuum cushion and ATLAS aiming device (both, Medical Intelligence GmbH, Schwabmünchen, Germany) and a co-shareholder in its financial returns.

Declaration of interest: The authors report no other conflicts of interest. The authors alone are responsible for the content and writing of the paper.