Glottis Closure Influences Tracheal Size Changes in Inspiratory and Expiratory CT in Patients with COPD.
The opened or closed status of the glottis might influence tracheal size changes in inspiratory and expiratory computed tomography (CT) scans. We investigated if the glottis status makes the tracheal collapse differently correlate with lung volume difference between inspiratory and expiratory CT scans.



Forty patients with chronic obstructive pulmonary disease whose glottis was included in the acquired scanned volume for lung CT were divided into two groups: 16 patients with the glottis closed in both inspiratory and expiratory CT, and 24 patients with the glottis open in at least one CT acquisition. Lung inspiratory (Vinsp) and expiratory (Vexp) volumes were automatically computed and lung ΔV was calculated using the following formula: (Vinsp - Vexp)/Vinsp × 100. Two radiologists manually measured the anteroposterior diameter and cross-sectional area of the trachea 1 cm above the aortic arch and 1 cm above the carina. Tracheal collapse was then calculated and correlated with lung ΔV.



In the 40 patients, the correlations between tracheal Δanteroposterior diameter and Δcross-sectional area at each level and lung ΔV ranged between 0.68 and 0.74 (ρ) at Spearman rank correlation test. However, in the closed glottis group, the correlations were higher for all measures at the two levels (ρ range: 0.84-0.90), whereas in the open glottis group, correlations were low and not statistically significant (ρ range: 0.29-0.34) at the upper level, and moderate at the lower level (ρ range: 0.51-0.55).



A closed or open glottis influences the tracheal size change in inspiratory and expiratory CT scans. With closed glottis, the tracheal collapse shows a stronger correlation with the lung volume difference between inspiratory and expiratory CT scans.
Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, Florence 50134, Italy. Electronic address: nikolandini@hotmail.it.
Nicholas
N
Landini
Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Via Venezia 52, Cesena 47521, Italy.
Stefano
S
Diciotti
Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, Florence 50134, Italy.
Monica
M
Lanzetta
Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, Florence 50134, Italy.
Francesca
F
Bigazzi
Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, Florence 50134, Italy.
Gianna
G
Camiciottoli
Department of Clinical and Experimental Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, Florence 50134, Italy.
Mario
M
Mascalchi
D000368:Aged; D045853:Exhalation; D005260:Female; D005931:Glottis / Q000000981:diagnostic imaging* / Q000502:physiology; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D013990:Tidal Volume; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014132:Trachea / Q000000981:diagnostic imaging* / Q000503:physiopathology*
COPD; CT; Tracheal collapse; glottis; lung volume