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. 2017 Jul;44(7):3594-3603.
doi: 10.1002/mp.12274. Epub 2017 May 22.

Computed tomography quantification of tracheal abnormalities in COPD and their influence on airflow limitation

Leticia Gallardo Estrella  1 , Esther Pompe  2 , Jan-Martin Kuhnigk  3 , David A Lynch  4 , Surya P Bhatt  5   6   7 , Bram van Ginneken  1   3 , Eva Marjolein van Rikxoort  1   3
Affiliations

Computed tomography quantification of tracheal abnormalities in COPD and their influence on airflow limitation

Leticia Gallardo Estrella et al. Med Phys. 2017 Jul.

Abstract

Purpose: To present a method to automatically quantify tracheal morphology changes during breathing and investigate its contribution to airflow impairment when adding CT measures of emphysema, airway wall thickness, air trapping and ventilation.

Methods: Because tracheal abnormalities often occur localized, a method is presented that automatically determines the most abnormal trachea section based on automatically computed sagittal and coronal lengths. In this most abnormal section, trachea morphology is encoded using four equiangular rays from the center of the trachea and the normalized lengths of these rays are used as features in a classification scheme. Consequently, trachea measurements are used as input for classification into GOLD stages in addition to emphysema, air trapping and ventilation. A database of 200 subjects distributed across all GOLD stages is used to evaluate the classification with a k nearest neighbour algorithm. Performance is assessed in two experimental settings: (a) when only inspiratory scans are taken; (b) when both inspiratory and expiratory scans are available.

Results: Given only an inspiratory CT scan, measuring tracheal shape provides complementary information only to emphysema measurements. The best performing set in the inspiratory setting was a combination of emphysema and bronchial measurements. The best performing feature set in the inspiratory-expiratory setting includes measurements of emphysema, ventilation, air trapping, and trachea. Inspiratory and inspiratory-expiratory settings showed similar performance.

Conclusions: The fully automated system presented in this study provides information on trachea shape at inspiratory and expiratory CT. Addition of tracheal morphology features improves the ability of emphysema and air trapping CT-derived measurements to classify COPD patients into GOLD stages and may be relevant when investigating different aspects of COPD.

Keywords: COPD; CT; automatic quantification; lung; trachea.

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Conflict of interest statement

D. A. L. is a consultant for Parexel Inc, Veracyte Inc, Boehringer Ingelheim Inc, Genentech/Roche Inc, and Siemens Inc. S. P. B. is supported by NIH under Grant No. K23HL133438. B. v. G. receives research funding and royalties from MeVis Medical Solutions, Delft Imaging Systems and Toshiba. He is co‐founder and shareholder of Thirona BV. E.M. v. R. is co‐founder and shareholder of Thirona BV.

Figures

Figure 1
Figure 1
Illustration of saber‐sheath trachea across stages. (a) Axial inspiratory scan image showing a saber‐sheath trachea from a GOLD 1 patient (TI = 0.49). (b) Detail view of the tracheal cross‐section in (a). (c) Axial inspiratory scan image showing a saber‐sheath trachea from a GOLD 4 patient (TI = 0.47). (d) Detail view of the tracheal cross‐section in (c). In the detail views, the trachea segmentation is outlined in black. The intersection of the four equiangular rays with the trachea segmentation is highlighted in with grey circles. The white rays represent the distances used for the computation of the TI.
Figure 2
Figure 2
Illustration of maximum narrowing detection between inspiration and expiration. The figure shows the inspiration‐expiration pair of sections with the minimum T. (a) Axial inspiratory scan image showing the inspiration section with the lowest T. (b) Detail view of the tracheal cross‐section in (a). (c) Axial expiratory scan corresponding to the inspiratory image in (a). (d) Detail view of the tracheal cross‐section in (c). In the detail views, the trachea segmentation is outlined in black. The four equiangular rays cast (at 0, 90, 180 and 270 degrees) from the center to the boundary of the trachea are shown in white, and the intersections of the rays with the trachea segmentation are highlighted with grey circles. These rays also represent the distances used for the computation of the T. The dashed rays depict the distance quantified by the tracheal features at 0 degrees.
Figure 3
Figure 3
Results of the classification into GOLD stages. The number of features for every setting is stated between parenthesis. Emph = emphysema; air trap = air trapping, SFFS = sequential forward floating selection. Dashed lines depict measures that indicate better performance with higher values. Solid lines depict measures that indicate better performance with lower values. [Color figure can be viewed at wileyonlinelibrary.com]
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References

    1. Global Initiative for Chronic Obstructive Lung Disease (GOLD) . Global strategy for the diagnosis, management and prevention of COPD. http://www.goldcopd.org. 2014.
    1. Mets OM, Schmidt M, Buckens CF, et al. Diagnosis of chronic obstructive pulmonary disease in lung cancer screening computed tomography scans: independent contribution of emphysema, air trapping and bronchial wall thickening. Respir Res. 2013;14:59. - PMC - PubMed
    1. Mohamed Hoesein FAA, de Jong PA, Lammers J‐WJ, et al. Contribution of CT quantified emphysema, air trapping and airway wall thickness on pulmonary function in male smokers with and without COPD. COPD. 2014;11:503–509. - PubMed
    1. Greene R. “saber‐sheath" trachea: relation to chronic obstructive pulmonary disease. Am J Roentgenol. 1978;130:441–445. - PubMed
    1. Eom JS, Lee G, Lee HY, et al. The relationships between tracheal index and lung volume parameters in mild‐to‐moderate COPD. Eur J Radiol. 2013;82:e867–e872. - PubMed

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