Hospital Universitari de Bellvitge, Barcelona, Spain
Copyright 2016, American College of Chest Physicians. All Rights Reserved.
SESSION TITLE: Procedures 1 - EMN/BT/Rigid/Cryo
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 26, 2016 at 01:30 PM - 02:30 PM
PURPOSE: A main weakness of virtual bronchoscopic navigation (VBN) is unsuccessful segmentation of distal branches approaching peripheral pulmonary nodules (PPN). CT scan acquisition protocol is pivotal for segmentation covering the utmost periphery. We hypothesize that application of continuous positive airway pressure (CPAP) during CT acquisition could improve visualization and segmentation of peripheral bronchi. The purpose of the present pilot study is to compare quality of segmentations under 4 CT acquisition modes: inspiration (INSP), expiration (EXP) and both with CPAP (INSP-CPAP and EXP-CPAP).
METHODS: In 5 patients 320-detector row CT scans (Aquilion ONE™, Toshiba, Japan) with slice thickness of 0.5 mm were performed in the 4 modes. CPAP was generated with EzPAP® (Smiths Medical, USA) with pressures ranging 6-10 cmH2O for 3’ immediately before CT acquiscion. Segmentations were obtained with a VBN system (LungPoint®, Broncus, USA) and those 2 most distal bronchi per lobe were selected. Comparisons were made based upon the number of bifurcations (BIF) achieved and absolute distance (DIST, in mm) from carina to the very end of the selected bronchi. Relative distances (DIST%) were computed dividing DIST by lung's largest axis measured from apex to diaphragm.
RESULTS: Data were analyzed with a 2-way ANOVA test. DIST and BIF were significantly different in the 4 modes (p<0.05) while DIST% was not (p=0.054). When comparing right and left lungs we observed a statistically significant difference in DIST (p<0.05) while this difference was not significant in neither BIF nor DIST%.
CONCLUSIONS: 1) Absolute distance and bifurcations are not the best measurements for comparing segmentations since they are subject to dynamic changes of the lung during breathing. 1) Relative distance may be a better score to assess the quality of a segmentation both within and between individuals. 3) Relative distances are larger when combining expiration with CPAP. This can be explained by the combination of a shorter distance to the nodule in expiration and a better segmentation of the airway with the application of CPAP. Although this result is not statistically significant it encourages further analysis of CPAP-enhanced CT.
CLINICAL IMPLICATIONS: Using CPAP during CT acquisition might improve visualization and segmentation of peripheral airways and therefore achievement of peripheral pulmonary nodules. Funded by LMTV3-20133510, FUCAP, SOCAP, FUCAP, FIS PI09/90917, DPI2015-65286-R, 2014-SGR-1470 and PROD-2014-00065.
DISCLOSURE: The following authors have nothing to disclose: Marta Diez-Ferrer, Debora Gil, Elena Carreño, Susana Padrones, Samantha Aso, Vanesa Vicens, Cubero Noelia, Rosa Lopez Lisbona, Carles Sanchez, Agnes Borras, Antoni Rosell
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