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    Biomedical Imaging and Instrumentation

    (D-152) Utilizing Airway Geometry for Chronic Obstructive Pulmonary Disease Phenotyping

    Saturday, October 14, 2023
    9:30 AM – 10:30 AM PDT
    Location: Exhibit Hall - Row D - Poster # 152

      Presenting Author(s)

    • Jatin S. Dhamrait (he/him/his)

      Undergraduate Research Assistant
      The University of Iowa Roy J. Carver Department of Biomedical Engineering
      Springfield, Illinois, United States

      • Co-Author(s)

    • EC

      Erik J. Cole, B.S.

      Graduate Researcher
      The University of Iowa Roy J. Carver Department of Biomedical Engineering, United States

    • LV

      Luis G. Vargas Buonfiglio, M.D.

      Pulmonary Fellow
      The University of Iowa Roy J. and Lucille A. Carver College of Medicine, United States

      • Primary Investigator(s)

    • JR

      Joseph M. Reinhardt, Ph. D.

      Professor and Department Executive Officer, Biomedical Engineering Roy J. Carver Chair in Biomedical
      University of Iowa, United States

    Introduction:: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States in the year 2018 (1). COPD is a combination of two phenotypes: the “chronic bronchitis phenotype” and the “emphysematous phenotype.” Despite these well-defined phenotypes, diagnoses are typically subjective, determined by the patient’s symptoms and evaluation of their chest computed tomography (CT). Furthermore, existing literature suggests that COPD alters the airway geometry, changing the angle between the trachea and the main bronchi (2). We seek to explore this phenomenon in more detail, asking does the tracheobronchial angle (TBA) correlate with lung obstruction? Does the TBA differ significantly in those with COPD, bronchitis, or emphysema as diagnosed by a physician reviewing a chest CT scan? 

    Materials and Methods:: Airway measurements were obtained from APOLLO (VIDA Diagnostics, Coralville, IA) pre-processed CT scan data from individuals with COPD enrolled in the SubPopulations and InteRmediate Outcome Measures In COPD Study (SPIROMICS). 543 subjects were randomly selected from the SPIROMICS cohort and their CT-based airway tree segmentations were used to calculate airway geometry measurements. After processing, the TBA was extracted for examination. An experienced cardiothoracic radiologist reviewed each scan and determined if COPD, emphysema, and bronchitis were present. The forced lung expiratory volume in one second (FEV1) to forced vital capacity (FVC) ratio of a subject (a measure of airflow obstruction), COPD diagnosis, emphysema diagnosis, and bronchitis diagnosis were selected for comparison to the TBA. 

    Results, Conclusions, and Discussions::

    The data suggests that the TBA correlates significantly with FEV1/FVC. The TBA is significantly different in COPD diagnosed by physician from a chest CT scan; individuals with COPD displayed a smaller TBA. Comparable results and trends were found for subjects with emphysema. Alternatively, the TBA is not significantly different in subjects with bronchitis. Therefore, the TBA could provide valuable insight into differentiating the COPD phenotypes; it can be an objective measure to distinguish emphysema from bronchitis. 




    One hypothesis to explain these findings is related to the pathophysiology of the two COPD phenotypes. Individuals with emphysematous symptoms tend to have hyperinflated lobes; hyperinflation could cause the right and left lungs to press against the inside walls of the thoracic cavity, decreasing the TBA. However, bronchitis does not alter the lobe size or cause hyperinflation; therefore, its severity would not affect the TBA. 




    Further work is needed to analyze the relationships between lung geometry and pulmonary function in their use in the clinic. Previous studies have only looked at the TBA and right or left upper lobe angles, but the methodology developed in this study has the capacity to examine all CT-visible bifurcations in the lung airway tree. Our approach could also provide insights into using TBA as a diagnostic measure for emphysematous tissue per lobe by comparing the TBA to the amount of air in each lobe.  




    Acknowledgements (Optional): :

    We thank VIDA Diagnostics Inc. for pre-processing the data and SPIROMICS for providing the data used in this study. SPIROMICS was supported by contracts from the NIH/NHLBI (HHSN268200900013C, HHSN268200900014C, HHSN268200900015C, HHSN268200900016C, HHSN268200900017C, HHSN268200900018C, HHSN268200900019C, HHSN268200900020C), grants from the NIH/NHLBI (U01 HL137880, U24 HL141762, R01 HL182622, and R01 HL144718), and supplemented by contributions made through the Foundation for the NIH and the COPD Foundation from Amgen; AstraZeneca/MedImmune; Bayer; Bellerophon Therapeutics; Boehringer-Ingelheim Pharmaceuticals, Inc.; Chiesi Farmaceutici S.p.A.; Forest Research Institute, Inc.; Genentech; GlaxoSmithKline; Grifols Therapeutics, Inc.; Ikaria, Inc.; MGC Diagnostics; Novartis Pharmaceuticals Corporation; Nycomed GmbH; Polarean; ProterixBio; Regeneron Pharmaceuticals, Inc.; Sanofi; Sunovion; Takeda Pharmaceutical Company; and Theravance Biopharma and Mylan/Viatris. 




    Disclosure: Joseph Reinhardt is a shareholder in VIDA Diagnostics Inc.  




    References (Optional): :


    1. Xu J, Murphy SL, Kochanek KD, Arias E. Mortality in the United States, 2018. NCHS Data Brief. 2020;355,1-8. Accessed March 12, 2022. 

    2. Onoe R, et al. 3D-measurement of tracheobronchial angles on inspiratory and expiratory chest CT in COPD: Respiratory changes and correlation with airflow limitation. Int J Chron Obstruct Pulmon Dis. 2018;13,2399-2407.