Electromagnetic Navigation vs Fluoroscopy in Aortic Endovascular Procedures - A Phantom Study
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Purpose: To explore the possible benefits of electromagnetic (EM) navigation versus conventional fluoroscopy during abdominal aortic endovascular procedures. Methods: The study was performed on a phantom representing the abdominal aorta. Intraoperative cone-beam computed tomography (CBCT) of the phantom was acquired and merged with a preoperative multidetector CT (MDCT). The CBCT was performed with a reference plate fixed to the phantom that, after merging the CBCT with the MDCT, facilitated registration of the MDCT volume with the EM space. An EM field generator was stationed near the phantom. Open source navigation software was used to display EM-tracked instruments within the 3D image volume. Fluoroscopy was performed using a floor-mounted C-arm system. Five operators of varying prior experience performed a series of renal artery cannulations using modified instruments, alternatingly using fluoroscopy or EM navigation as the sole guidance method. Procedure durations and associated radiation dosages were noted along with the number of procedures that were complicated by loss of guidewire insertion. Results: A total of 120 cannulations were performed of which 60 were guided using each technique. The median procedure durations were 41.5 and 34.5 seconds for the fluoroscopy- and EM-guided procedures, respectively. No significant difference in the procedure duration was found between the two modalities (p = 0.736). Only EM navigation showed a significant reduction in procedure duration in the latter half of its cannulation series compared with the first half (p = 0.004). The median fluoroscopy radiation dosage was 8.36 μGy/m2. EM navigation required only a CBCT dosage of 302.78 μGy/m2. Three EM-guided and zero fluoroscopy-guided procedures were associated with loss of guidewire insertion. Conclusion: Our findings indicate that EM navigation is not inferior to fluoroscopy in terms of the ability to guide endovascular interventions. Its utilization may be of particular interest in complex interventions where adequate visualization or minimal use of contrast agents is critical. In vivo studies featuring an optimized implementation of EM navigation should be conducted. Keywords: Fluoroscopy, electromagnetic navigation, abdominal aorta, endovascular procedures, 3D tracking.