Cone Beam CT Guided Robotic Navigational Bronchoscopy

Navigation bronchoscopy (NB) has been used for more than a decade to access peripheral and central parenchymal lung lesions bronchoscopically. Traditionally standard fluoroscopy using C-arm is used to confirm the location and guide the biopsy instruments under real-time guidance. With availability of Cone Beam CT, fluoroscopic images of much higher quality and resolution can be obtained intra-operatively. It also enables the bronchoscopist to obtain intraoperative CT images and confirm the exact location of the lesion and the Bronchoscopic biopsy catheter or the biopsy instruments.

Recently we have had significant advancements in the technology to guide and operate the instruments used to reach these hard to reach lesions within the lungs. We have different fixed angle electromagnetic guided platforms, articulating robotic electromagnetic guided platforms and articulating robotic shape sensing guided platforms.

At my institution, lung nodules/masses requiring NB has evolved over the years starting from Medtronic Super-Dimension Version 7 Electromagnetic Navigational Bronchoscopy (ENB) system to ION Robotic Bronchoscopy platform (RNB). All the procedures are done under fluroscopic guidance which has also evolved from a regular C-Arm to Philips Cone Beam CT with Augmented Fluoroscopy.

During this evolution we have had Medtronic Super-D ENB with 2D fluoro followed by Medtronic Super-D ENB with CBCT and Augmented fluoroscopy and now have the Ion robotic platform with CBCT and Augmented fluoroscopy with low dose protocol.

All the lesions are confirmed using peripheral/radial Endobronchial Ultrasound (rEBUS). Once the appropriate location is reached, biopsy is obtained using FNA (18G or 21G), Single or Triple needle brush, Transbronchial forceps and Bronchoalveolar lavage is done for cytology or micro studies if needed.

A pathologist is present on site for all the cases to review the slides and assist in diagnosis. All the cases are done under general anesthesia through endotracheal tube.

Also, all the NB procedures have been performed by one Interventional Pulmonologist since August 2017.

For the interventional arm, all the aspects will remain the same except that the procedure will utilize Ion Robotic bronchoscopy platform and pre-operatively every patient will undergo incentive spirometry, dual short acting bronchodilator treatment and will be maintained at relatively higher PEEP and Lower FiO2 than before.

The diagnostic yield will be compared to the patients who underwent procedure using Super-D Electromagnetic platform with CBCT and Augmented Fluoroscopy.

All cases are still done in Hybrid ORand all the patients are completely paralyzed intra-operatively. Also, all procedures in both arms will use a Philips Azurion 7 C20 FlexMove system with Emboguide, 3D Segmentaion and Overlay tools. This enables the bronchoscopist to obtain a CT scan of the chest and also segment out the lesion(s) of interest and to overlap the 3-D image of the lesion on live fluoroscopy in all 3 dimensions.

During the ENB and RNB procedures, at least 1 full Xpert CT is obtained, mostly after completing the airway registration and advancing the guided catheter to the lesion of interest. Once the extended working channel and the locatable guide or The robotic articulating catheter is advanced to the lesion using ENB/Shape sensing guidance, the catheter is held at that position and patient is maintained in inspiratory breath hold and Cone Beam CT is used to obtain the Xpert CT that shows the lesion and surrounding lungs, chest and mediastinal structures in the surrounding area of the chest. This is then used to analyze the location of the lesion and the lesion of the extended working channel/robotic catheter and the biopsy instruments in relation to the lesion. The lesion is then segmented and EmboGuide + Overlay feature is used to project a 3D view of the lesion on the live fluoroscopic images in all three axis. This also allows the bronchoscopist to obtain Anterior-posterior, Lateral and oblique views at various angles while maintaining the 3D overlap.

Additional CT scans might be obtained intra-operatively if needed to guide the biopsy catheter appropriately towards the lesion.

Due to the live nature of the Cone Beam CT, it is much more capable of providing accurate guidance regarding the location of the lesion and the biopsy instruments. hence, in case of any discrepancy, information provided by Cone Beam CT is considered more reliable and used with higher confidence.

Rest of the steps involved in procedure are similar between the control and the interventional arm including the surgeon, type of biopsy instruments, use of peripheral Endobronchial Ultrasound and availability of on-site pathologist. The biopsy instruments include transbronchial needle for FNA, Single or triple needle brush and transbronchial forceps. Bronchoalveolar lavage is also obtained at the end via working channel.

All the patients undergoing biopsy of the peripheral/central lung lesions using ENB/RNB also undergo Convex EBUS guided mediastinal surveillance and EBUS-TBFNA of any Lymph Node that appears to be greater than 5 mm on EBUS exam.

My study aims to study the difference in diagnostic yield and sensitivity of electromagnetic navigational bronchoscopy with fixed angle catheter vs robotic shape sensing bronchoscopy with articulating catheter while using Cone Beam CT with segmentation, 3-D overlay and CT augmented fluoroscopy for diagnosis of peripheral and central lung lesions including lung nodules and masses which could not be directly accessed using just white light bronchoscope.