Effect of Electromagnetic Navigation on CT-Guided Percutaneous Thermal Ablation or Biopsy of Lung Tumors Chaitan K. Narsule 1, Avneesh Gupta 2, Michael I. Ebright 1, Ricardo Sales dos Santos 3, Roberto Rivas 1, Benedict D. T. Daly 1, Hiran C. Fernando 1 1 Department of Cardiothoracic Surgery, Boston University School of Medicine, Boston, MA 2 Department of Radiology, Boston University School of Medicine, Boston, MA 3 Department of Thoracic Surgery, Albert Einstein Israeli Hospital, São Paulo, Brazil
Disclosures Dr. Fernando Grant support from Veran Medical Technologies, Inc.
Electromagnetic Navigation (EMN) Adjunctive body imaging modality Low power magnetic field is generated Comparable to the Earth s magnetic field An instrument s movement is tracked and navigated relative to existing CT imaging No known long-term effect with human tissue
EMN as a Human GPS Commercial GPS Download maps of towns Signals from satellite to a receiver help determine position of receiver relative to downloaded maps
EMN as a Human GPS Human GPS Download imaging of body region Signals from EMN system to the device help determine position of device relative to downloaded body images
Electromagnetic Navigation Allows for new opportunities for the treatment of thoracic surgery patients Extended bronchoscopic procedures Biopsy for peripheral lung masses Placement of fiducials for SBRT treatment Dye injection to facilitate wedge resection Percutaneous biopsy or ablation of lung tumors
CT-Guided Thermal Ablation of Lung Tumors
CT-Guided Biopsy or Thermal Ablation of Lung Tumors Using a finder needle Spinal needle Thermal ablation probe External Marker Vertical grid Transverse laser from CT gantry CT Fluoroscopy Series of 3 images/sec acquired to confirm device positioning All require additional scans and radiation exposure to make needle or probe adjustments External marker
Percutaneous Thoracic Electromagnetic Navigation: Veran ig4 system Steps with EM navigation: 1) Patient undergoes CT scan with tracker pads in place 2) CT is imported to the EMN system 3) EMN system positioned over patient 4) Procedure performed using imported CT
EMN tracker placed on probe
EMN-guided device placement using imported CT imaging Navigation outside CT gantry using EMN System monitor view (using IMPORTED CT imaging)
EMN-guided device placement Final confirmation of device position with CT fluoroscopy
Initial experience with EMN for RFA and Biopsy 10 patients 19 EMN-guided procedures for pulmonary nodules Mean number of instrument adjustments required was 1.2 Mean time 5.2 minutes Santos RS et al. Ann Thorac Surg. 2010;89:265-8.
Methods Inclusion Criteria Patients with lung tumors or pulmonary metastases High-risk for pulmonary resection Percutaneous thermal ablation selected as primary therapy Provided informed consent
Methods Randomization CT-guided intervention alone EMN with CT-guided intervention Each procedure (biopsy or ablation) defined as one intervention
Data and Outcomes Measured Tumor diameter Distance from skin to tumor Body-mass index Tumor pathology Time to complete each intervention Number of adjustments Number of CT scans Number of skin punctures CT fluoroscopy time Post-operative pneumothorax (and need for pigtail catheter) Days with catheter Hospital length of stay
Results 17 patients treated over 23 month period 7 women 23 procedures (20 ablations, 3 biopsies) Mean age: 72 years (60-84 years) Mean BMI: 29.8 (range 22-36.1)
Characteristics: All procedures Mean tumor diameter 2.0 (0.6-4.3) cm Radiofrequency ablation (RFA) 8 Microwave ablation (MWA) 12 Biopsies 3 Non-small cell lung cancer 12 Pulmonary metastases 8
Randomization 17 patients 7 patients 10 patients EMN with CT-guided intervention CT-guided intervention alone
Comparative Analysis EMN group CT-only group p-value Tumor size 1.45 cm 2.29 cm 0.077 Time to complete intervention 7.6 min 19 min 0.022 # of skin punctures 1 1.25 0.082 # of adjustments 5.6 11.8 0.203 # of CT scans 7 15 0.204 CT fluoroscopy time 21.3 sec 34.3 sec 0.345
Perioperative Data Pneumothorax 14 patients Pleural catheter 13 patients Median # days with pleural catheter 1 day (range 1-4) Median length of stay 2 days (range 1-4)
Conclusions EMN is a useful adjunct to assist with CT-guided thermal ablation of lung tumors and pulmonary metastases. It reduces the amount of time needed for the completion of CT-guided thermal ablation of lung tumors. More study necessary to determine if a benefit exists in terms of reduced radiation exposure.
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