NOVEL X-RAY VELOCIMETRY-BASED QUANTITATIVE REGIONAL LUNG FUNCTION ANALYSIS TO ASSESS RISK OF RADIATION-INDUCED PNEUMONITIS AND PULMONARY FIBROSIS

Abstract

SESSION TITLE: Late Breaking Pulmonary Fibrosis SESSION TYPE: Original Investigations PRESENTED ON: 10/22/2019 08:45 AM - 09:45 AM PURPOSE: Quantification of small changes in lung function is necessary for early diagnosis and intervention in chronic lung diseases. Pneumonitis is a frequent complication of lung radiation that currently has no known therapy and can only be diagnosed late when it manifests changes in the pulmonary function tests (PFT). Unlike existing PFT, X-ray Velocimetry (XV) technology uniquely measures 4D lung motion to quantify regional lung function with high resolution and accuracy providing a novel diagnostic tool for early assessment of risk of radiation induced pneumonitis and/or pulmonary fibrosis. METHODS: This study was primarily designed to assess the performance of XV technology in comparison to other clinically available measures (spirometry, CT) in diagnosing radiation pneumonitis. Patients with a predicted risk for pneumonitis of 25% (V20 Gy>20%) were consented and enrolled in this study. In order to test the capacity of XV to detect changes in lung function over time, XV-scans were acquired pre-treatment, weekly on treatment and at 4-months and 12-months following treatment in combination with PFTs, and/or 4DCT or CT. RESULTS: Compared to PFT, the tidal volume and ventilation (Heterogeneity Index, HI% and Ventilation Defect Percentage, VDP) data from XV scans obtained 1 week apart showed excellent reproducibility in preliminary analysis. Moreover, derived global metrics such as ventilation heterogeneity and VDP varied by less than 2% for each patient analyzed. In the case of normal lung function (as indicated by PFT), XV scan results were consistent over multiple days, despite variability in imaging conditions. In the next case, XV and PFT measurements at 4-months and 12-months post-treatment were validated. At 4-months this subject’s FEV1 was >100% of expected levels for normal lung function, and the FEV1/FVC ratio was 1.07. By 12-months, FEV1s had decreased to 81% of expected, with FEV1/FVC = 0.89. Similarly, XV indicates a moderate change in lung function over this period, with an increase in HI from 56.2% to 66.1% and an increase in VDP from 7.1% to 11.6%. Moreover, contour maps of specific ventilation highlight changes in the regional distribution of ventilation. The lower region of the right lung was substantially less ventilated at twelve months post-treatment, with compensation occurring in other regions, showing the potential of XV in capturing regional lung function changes not available from PFT. CONCLUSIONS: This ongoing trial demonstrate that XV is repeatable and sensitive, detecting modest regional changes in lung function, such as the location of abnormally ventilated regions that may be an early indicator for lung fibrosis. CLINICAL IMPLICATIONS: XV analysis using existing fluoroscopes, has significantly lower radiation-exposure (compared to CT), and huge potential for early detection and treatment of a variety of lung diseases. DISCLOSURES: Employee relationship with 4Dx Limited Please note: $20001 - $100000 Added 06/20/2019 by Richard Carnibella, source=Web Response, value=Salary No relevant relationships by John DeMarco, source=Web Response Employee <br Employee relationship with 4Dx Inc Please note: >$100000 Added 06/16/2019 by Jonathan Dusting, source=Web Response, value=Salary Owner/Founder relationship with 4Dx Please note: >$100000 Added 06/21/2019 by Andreas Fouras, source=Web Response, value=Ownership interest Owner/Founder relationship with 4Dx Please note: >$100000 Added 06/21/2019 by Andreas Fouras, source=Web Response, value=Ownership interest Employee relationship with 4Dx Please note: >$100000 Added 06/20/2019 by Robert Jamison, source=Web Response, value=Salary Owner/Founder relationship with 4Dx Please note: >$100000 Added 06/20/2019 by Robert Jamison, source=Web Response, value=Ownership interest No relevant relationships by Cynthia Martin, source=Admin input Employee relationship with 4Dx Please note: $20001 - $100000 Added 06/20/2019 by Punit Shah, source=Web Response, value=Salary No relevant relationships by Stephen Shiao, source=Web Response Employee relationship with 4Dx Limited Please note: >$100000 Added 06/20/2019 by Neeraj Vij, source=Web Response, value=Salary Employee relationship with 4Dx Please note: $20001 - $100000 Added 06/20/2019 by David Wenger, source=Web Response, value=Salary Employee relationship with 4Dx Limited Please note: $20001 - $100000 Added 06/20/2019 by Alex Winnett, source=Web Response, value=Salary