Author of

• 12759

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  P3.17 - Poster Session 3 - Bronchoscopy, Endoscopy (ID 185)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12763

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    P3.17-004 - Breath-hold low dose CT immediately following PET/CT enables good quality Virtual Bronchoscopy prior to EBUS guide sheath biopsy (ID 2109)

    09:30 - 09:30  |  Author(s): D. Macfarlane
    • Abstract

    Background
    Virtual Bronchoscopy (VB) facilitates localization of small lesions at EBUS Guide sheath(GS). A good quality CT to create the VB can be problematic to obtain in a timely fashion. Most lung cancer patients require PET, hence we explored options of getting the VB CT at PET upon initial referral prior to EBUS GS.

    Methods
    We compared VB results for consecutive CTs acquired in one of 3 ways. These were: Group1 :reconstructed CT from the PET/CT ( tidal breathing), Group 2: a dedicated low dose inspiratory breath-hold CT as part of PET/CT, and Group 3 conventional diagnostic CT. CTs had volumetric acquisition and 1 mm overlapping cuts were derived giving at least 600 DICOM images per scan. DICOM images were loaded onto a Lung Point® VB device and VB created. This device gives automated results for the number of bronchial divisions visible, and nearest distance to lesion in question after creation of the VB. Data for Dose Length Product (DLP) and CT Dose Index (CTDI) were obtained for each scan. DLP for Group 1 included whole body CT whereas DLP for Group 2 is stated just for the Thorax CT.

    Results
    

    	Group 1 Tidal breathing	Group2 Breath hold	Group3 Conventional CT
    n	18	17	20
    Lesion size (mm)	21.1± 12.0	23.8±11.0	21.6±7.2
    Bronchial divisions	3.25±0.9	4.49±1.1, p<0.01	4.55±0.5 p<0.01
    proximity to target lesion (mm)	25.8±19.5	6.7±6.3, p<0.001 cf Gp1	13.3±9.2, p<0.02 cf Gp1
    DLP	435 ± 31	173 ± 77	341 ±94, p<0.001 cf Gp 2
    CTDI	3.9 ± 1.3	4.1 ± 1.9	8.9±2.9, p<0.001 cf Gp2
    % lesions reached at EBUS GS	83	85	90
    % positive pathology at EBUS GS	58	54	63

    In Group 2 unexpected positive mediastinal nodes were seen on PET enabling staging and diagnostic EBUS TBNA confirming malignancy to be done instead of EBUS GS in 3 patients. Poor VB results with the reconstructed CT were due to underlying COPD with small airway closure and hence inability of the software to detect these small airways; (scans acquired in both inspiration and expiration).

    Conclusion
    Low dose single breath-hold CT at the time of PET gives at least equivalent results to dedicated CT with far less radiation exposure, and is technically superior to reconstructed CT. Higher visualised bronchial number allows closer proximity to lesions by the directed path. Obtaining this CT prior to EBUS GS means no additional high dose CT is required and additional nodal staging results with the PET can make for better procedural decision making.