title: Excessive collapsibility of bronchi in bronchiectasis: evaluation on volumetric expiratory high-resolution CT.
abstract: OBJECTIVE
  To evaluate the frequency and severity of bronchomalacia, defined as excessive collapsibility of bronchi, in bronchiectasis; to compare the extent of air trapping in bronchiectasis patients with/without bronchomalacia; and to correlate the severity of bronchomalacia and the extent of air trapping versus pulmonary function.
  
  
  METHODS
  Forty-six patients with bronchiectasis evaluated by volumetric expiratory high-resolution computed tomography (CT) and pulmonary function tests were studied. The presence and severity of bronchomalacia were evaluated on contiguous axial high-resolution CT images using a 4-point scale. The extent of air trapping was graded on coronal reformations using a 5-point scale. Differences in the extent of air trapping in patients with/without bronchomalacia and the correlation between the severity of bronchomalacia and the extent of air trapping were investigated. The severity of bronchomalacia and the extent of air trapping were correlated with pulmonary function.
  
  
  RESULTS
  Of 46 patients with bronchiectasis, 32 patients (70%) had bronchomalacia. Air trapping was present in 43 patients (93%). The extent of air trapping in patients with bronchomalacia was significantly greater compared with the patients without bronchomalacia (P=0.0308). The correlation between the severity of bronchomalacia and extent of air trapping was not statistically significant (rs=0.029, P=0.8457).
  
  
  CONCLUSIONS
  The extent of air trapping in bronchiectasis patients with bronchomalacia was significantly greater compared with bronchiectasis patients without bronchomalacia, suggesting that the bronchomalacia is one of the underlying mechanisms of air trapping in bronchiectasis.
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. mnishino@bidmc.harvard.edu
authors.forename: Mizuki
authors.initials: M
authors.lastname: Nishino
authors.forename: Bettina
authors.initials: B
authors.lastname: Siewert
authors.forename: David H
authors.initials: DH
authors.lastname: Roberts
authors.forename: Shiva
authors.initials: S
authors.lastname: Gautam
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Boiselle
authors.forename: Vassilios
authors.initials: V
authors.lastname: Raptopoulos
authors.forename: Hiroto
authors.initials: H
authors.lastname: Hatabu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001980:Bronchi / Q000503:physiopathology*; D001982:Bronchial Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D001987:Bronchiectasis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*