Airway remodeling measured by multidetector CT is increased in severe asthma and correlates with pathology.
BACKGROUND
To prospectively apply an automated, quantitative three-dimensional approach to imaging and airway analysis to assess airway remodeling in asthma patients.


METHODS
Using quantitative software (Pulmonary Workstation, version 0.139; VIDA Diagnostics; Iowa City, IA) that enables quantitative airway segment measurements of low-dose, thin-section (0.625 to 1.25 mm), multidetector-row CT (MDCT) scans, we compared airway wall thickness (WT) and wall area (WA) in 123 subjects participating in a prospective multicenter cohort study, the National Institutes of Health Severe Asthma Research Program (patients with severe asthma, n = 63; patients with mild-to-moderate asthma, n = 35); and healthy subjects, n = 25). A subset of these subjects underwent fiberoptic bronchoscopy and endobronchial biopsies (n = 32). WT and WA measurements were corrected for total airway diameter and area: WT and WA, respectively.


RESULTS
Subjects with severe asthma had a significantly greater WT% than patients with mild-to-moderate asthma and healthy subjects (17.2 +/- 1.5 vs 16.5 +/- 1.6 [p = 0.014] and 16.3 +/- 1.2 [p = 0.031], respectively) and a greater WA percentage (WA%) compared to patients with mild-to-moderate asthma and healthy subjects (56.6 +/- 2.9 vs 54.7 +/- 3.3 [p = 0.005] and 54.6 +/- 2.4 [p = 0.003], respectively). Both WT% and WA% were inversely correlated with baseline FEV(1) percent predicted (r = -0.39, p < 0.0001 and r = -0.40, p < 0.0001, respectively) and positively correlated with response to a bronchodilator (r = 0.28, p = 0.002 and r = 0.35, p < 0.0001, respectively). The airway epithelial thickness measure on the biopsy sample correlated with WT% (r = 0.47; p = 0.007) and WA% (r = 0.52; p = 0.003). In the same individual, there is considerable regional heterogeneity in airway WT.


CONCLUSIONS
Patients with severe asthma have thicker airway walls as measured on MDCT scan than do patients with mild asthma or healthy subjects, which correlates with pathologic measures of remodeling and the degree of airflow obstruction. MDCT scanning may be a useful technique for assessing airway remodeling in asthma patients, but overlap among the groups limits the diagnostic value in individual subjects.
Aysola
Ravi S
RS
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Hoffman
Eric A
EA
Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA.
Gierada
David
D
Department of Radiology, Washington University School of Medicine, St. Louis, MO.
Wenzel
Sally
S
University of Pittsburgh Medical Center, Pittsburgh, PA.
Cook-Granroth
Janice
J
Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, IA.
Tarsi
Jaime
J
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Zheng
Jie
J
Division of Biostatistics, Washington University School of Medicine, St. Louis, MO.
Schechtman
Kenneth B
KB
Division of Biostatistics, Washington University School of Medicine, St. Louis, MO.
Ramkumar
Thiruvamoor P
TP
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Cochran
Rebecca
R
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Xueping
E
E
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Christie
Chandrika
C
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
Newell
John
J
National Jewish Medical and Research Center, Denver, CO.
Fain
Sean
S
University of Wisconsin, Madison, WI.
Altes
Talissa A
TA
Children's Hospital of Philadelphia, Philadelphia, PA.
Castro
Mario
M
Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO. Electronic address: castrom@wustl.edu.
D000293:Adolescent; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D001485:Basement Membrane / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020545:Respiratory Mucosa / Q000000981:diagnostic imaging* / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
D018927:Anti-Asthmatic Agents