PURPOSE: To evaluate, with thin-section computed tomography (CT), changes in bronchial cross-sectional area and lung attenuation induced by bronchial stimulation in patients with mild intermittent asthma, at a given lung volume monitored with pneumotachography.
MATERIALS AND METHODS: Twelve patients with mild intermittent asthma who were nonsmokers (National Institutes of Health staging) and six nonsmoking healthy volunteers, age and sex ratio–matched, were examined by using helical thin-collimation CT at the level of basal bronchi at 65% of total lung capacity. Three sets of acquisitions were obtained: at baseline and after inhalation of methacholine and then salbutamol. Cross-sectional areas of bronchi greater than 4 mm2 were segmented and calculated from CT images. Lung attenuation was measured in the anterior, lateral, and posterior areas of the right lung parenchyma. Gas trapping was evaluated by using thin-section CT at residual volume in six of the patients with asthma. Statistical analysis included two factors repeated-measurement analysis of variance and Mann-Whitney and Kruskal-Wallis nonparametric tests.
RESULTS: Bronchial cross-sectional areas and lung attenuation did not vary significantly compared with baseline values following bronchial challenge in healthy volunteers or patients with asthma. However, in patients with asthma, bronchial cross-sectional areas were significantly smaller than in healthy volunteers, except after inhalation of salbutamol. Lung attenuation and anteroposterior attenuation gradient were significantly higher in patients with asthma than in healthy patients (P < .001). Air-trapping scores were significantly higher after methacholine challenge.
CONCLUSION: Helical thin-collimation CT at controlled lung volume and at full expiration associated with bronchial challenge may help evaluate bronchoreactivity and inflammation in mild intermittent asthma.
© RSNA, 2002
- 1 National Heart Lung and Blood Institute. Guidelines for the diagnosis and management of asthma Expert panel report 2. Bethesda, Md: National Heart Lung and Blood Institute, 1999. NIH publication 98-4051. Google Scholar
- 2 Kraft M. The distal airways: are they important in asthma? Eur Respir J 1999; 14:1403-1417. Crossref, Medline, Google Scholar
- 3 Lynch DA, Newell JD, Tschomper BA, Cink TM, Newman LS, Bethel R. Uncomplicated asthma in adults: comparison of CT appearance of the lungs in asthmatic and healthy subjects. Radiology 1993; 188:829-833. Link, Google Scholar
- 4 Arakawa H, Webb WR. Air trapping on expiratory high-resolution CT scans in the absence of inspiratory scan abnormalities: correlation with pulmonary function tests and differential diagnosis. AJR Am J Roentgenol 1998; 170:1349-1353. Crossref, Medline, Google Scholar
- 5 Newman KB, Lynch DA, Newman LS, Ellegood D, Newell JD, Jr. Quantitative computed tomography detects air trapping due to asthma. Chest 1994; 106:105-109. Crossref, Medline, Google Scholar
- 6 Park CS, Müller NL, Worthy SA, Kim JS, Awadh N, Fitzgerald M. Airway obstruction in asthmatic and healthy individuals: inspiratory and expiratory thin-section CT findings. Radiology 1997; 203:361-367. Link, Google Scholar
- 7 Goldin JG, McNitt-Gray MF, Sorenson SM, et al. Airway hyperreactivity: assessment with helical thin-section CT. Radiology 1998; 208:321-329. Link, Google Scholar
- 8 Sylvester JT, Permutt S. Exhaled NO: first, hold your breath. J Appl Physiol 2001; 91:474-476. Crossref, Medline, Google Scholar
- 9 Fahy JV, Boushey HA, Lazarus SC, et al. Safety and reproducibility of sputum induction in asthmatic subjects in a multicenter study. Am J Respir Crit Care Med 2001; 163:1470-1475. Crossref, Medline, Google Scholar
- 10 American Thoracic Society. Guidelines for methacholine and exercise challenge testing, 1999. Am J Respir Crit Care Med 2000; 161:309-329. Crossref, Medline, Google Scholar
- 11 Pride NC. Physiology. In: Barnes PJ, Rodger IW, Thomson NC, eds. Asthma, basic mechanisms and clinical management. 2nd ed. London, England: Academic Press, 1992; 41-57. Google Scholar
- 12 Kirby JG, Juniper EF, Hargreave FE, Zamel N. Total lung capacity does not change during methacholine-stimulated airway narrowing. J Appl Physiol 1986; 61:2144-2147. Crossref, Medline, Google Scholar
- 13 Wollmer P, Albrechtsson U, Brauer K, Eriksson L, Jonson B, Tylèn U. Measurement of pulmonary density by means of x-ray computerized tomography. Chest 1986; 90:387-391. Crossref, Medline, Google Scholar
- 14 Préteux F, Fettita CI, Capderou A, Grenier P. Modeling, segmentation, and caliber estimation of bronchi in high resolution computerized tomography. J Electronic Imaging 1999; 8:36-45. Crossref, Google Scholar
- 15 Ng CS, Desai SR, Rubens MD, Padley SPG, Wells AU, Hansell DM. Visual quantification and observer variation of signs of small airways disease at inspiratory and expiratory CT. J Thorac Imaging 1999; 14:279-285. Crossref, Medline, Google Scholar
- 16 European Respiratory Society. Standardized lung function testing. Eur Respir J 1993; 6:1-100. Google Scholar
- 17 Skloot G, Permutt S, Togias A. Airway hyperresponsiveness in asthma: a problem of limited smooth muscle relaxation with inspiration. J Clin Invest 1995; 96:2393-2403. Crossref, Medline, Google Scholar
- 18 Fredberg JJ. Airway smooth muscle in asthma: flirting with disaster. Eur Respir J 1998; 12:1252-1256. Crossref, Medline, Google Scholar
- 19 Niimi A, Matsumoto H, Amitani R, et al. Airway wall thickness in asthma assessed by computed tomography. Am J Respir Crit Care Med 2000; 162:1518-1523. Crossref, Medline, Google Scholar
- 20 Haley KJ, Sunday ME, Wiggs BR, et al. Inflammatory cell distribution within and along asthmatic airways. Am J Respir Crit Care Med 1998; 158:565-572. Crossref, Medline, Google Scholar
- 21 Mitzner W, Brown RH. Potential mechanism of hyperresponsive airways. Am J Respir Crit Care Med 2000; 161:1619-1623. Crossref, Medline, Google Scholar
- 22 Brown RH, Croisille P, Mudge B, Diemer FB, Permutt S, Togias A. Airway narrowing in healthy humans inhaling methacholine without deep inspirations demonstrated by HRCT. Am J Respir Crit Care Med 2000; 161:1256-1263. Crossref, Medline, Google Scholar
- 23 Roche WR. Inflammatory and structural changes in the small airways in bronchial asthma. Am J Respir Crit Care Med 1998; 157:S191-S194. Crossref, Medline, Google Scholar
- 24 Verbanck S, Schuermans D, Noppen M, Van Muylem A, Paiva M, Vincken W. Evidence of acinar airway involvement in asthma. Am J Respir Crit Care Med 1999; 159:1545-1550. Crossref, Medline, Google Scholar
- 25 Bousquet J, Jeffery PK, Busse WW, Johnson M, Vignola AM. Asthma: from bronchoconstriction to airways inflammation and remodeling. Am J Respir Crit Care Med 2000; 161:1720-1745. Crossref, Medline, Google Scholar