Electromagnetic field-based navigation for percutaneous punctures on C-arm CT: experimental evaluation and clinical application

Abstract

The aim of this study was to prospectively evaluate the needle visualization and placement error and use of an electromagnetic field-based tracking navigation device for puncture procedures based on C-arm CT (CACT) images. A commercially available navigation device was mounted on an angiographic X-ray system setup for CACT. After the target was defined, needle placement was performed under real-time visualization of the virtual needle in CACT images. The final, real needle position was assessed by CACT. Punctures were performed in phantoms (n = 76) and in twelve patients (eight biopsies, three drainages, one injection). Procedure times, system error, user error and total error were assessed. In phantoms, mean total error was 2.3 +/- 0.9 mm, user error was 1.4 +/- 0.8 mm and system error was 1.7 +/- 0.8 mm. In the patient study, the targeted puncture was successful in all twelve cases. The mean total error was 5.4 mm +/- 1.9 mm (maximum 8.1 mm), user error was 3.7 +/- 1.7 mm, system error was 3.2 +/- 1.4 mm and mean skin-to-target time was less than 1 min. The navigation device relying on CACT was accurate in terms of needle visualization and useful for needle placement under both experimental and clinical conditions. For more complex procedures, electromagnetic field-based tracking guidance might be of help in facilitating the puncture and reducing both the puncture risk and procedure time.

C-Arm Cone-Beam CT Combined with a New Electromagnetic Navigation System for Guidance of Percutaneous Needle Biopsies: Initial Clinical Experience

“…The authors concluded that CT/EMT guidance led to high accuracy with regard to needle placement, thus reducing time and potentially radiation exposure in comparison with conventional CT alone. CACT/EMT guidance is a relatively new innovative technique [20,23]. Compared with data obtained with exclusive CT or CACT guidance in the literature [7, 12, 14, 24 -26], our results showed comparable diagnostic yield values for CACT/ EMT-guided biopsy procedures.…”

“…However, C-arm cone-beam CT images provide restricted image quality in terms of contrast resolution [15 -19]. An approach to improve the accuracy of tumor targeting despite lower image quality may be the coupling of C-arm cone-beam CT with an electromagnetic navigation system in the guidance of biopsies [20]. To date, only a few studies addressing the role of C-arm conebeam CT-based electromagnetic tracking (EMT) of percutaneous biopsies have been published, and this guiding technique seems to be relatively new to the field of interventional radiology [17,20].…”

“…An approach to improve the accuracy of tumor targeting despite lower image quality may be the coupling of C-arm cone-beam CT with an electromagnetic navigation system in the guidance of biopsies [20]. To date, only a few studies addressing the role of C-arm conebeam CT-based electromagnetic tracking (EMT) of percutaneous biopsies have been published, and this guiding technique seems to be relatively new to the field of interventional radiology [17,20]. Preliminary work describing the clinical efficacy of conebeam CT coupled with electromagnetic navigation in biopsy procedures has been reported [20].…”

“…To date, only a few studies addressing the role of C-arm conebeam CT-based electromagnetic tracking (EMT) of percutaneous biopsies have been published, and this guiding technique seems to be relatively new to the field of interventional radiology [17,20]. Preliminary work describing the clinical efficacy of conebeam CT coupled with electromagnetic navigation in biopsy procedures has been reported [20]. The outcome of these procedures has been reported in a small case series of patients with target lesions not sensitive for respiratory motion.…”

“…A control C-arm CT image with the needle in place could have been fused with the planning CT to calculate all relevant targeting errors such as total error, lateral error, longitudinal error, and angular error. However, a recent study has already addressed this topic and revealed accurate needle location in phantoms as well as in patients [20]. For that reason our study focused on the technical success of lesion targeting.…”