Differences in radiological/HRCT findings in eosinophilic bronchitis and asthma: implication for bronchial responsiveness.

BACKGROUND Airway hyperresponsiveness in asthmatics is considered to be one of the major consequences of airway inflammation and remodelling. Airway responsiveness is normal in patients with eosinophilic bronchitis (EB), despite eosinophilic inflammation of the airways comparable to that which occurs in asthmatics. Comparisons between asthma and EB should clarify the changes in airway morphology that are related specifically to AHR in asthmatics. METHODS Eighteen asthmatic patients, 15 patients with EB, and 11 healthy subjects were recruited. Airway wall area percentage (WA%), centrilobular prominence, and air trapping were compared using thin slice section computed tomography. RESULTS WA% was significantly greater in asthmatics than in patients with EB (72 (3.1)% v 54 (2.1)%, p = 0.032) and was similar in EB patients and controls (54 (2.1)% v 57 (1.8)%, p>0.05). Centrilobular prominence and air trapping were similar in EB patients and asthmatics and were significantly greater than in controls. CONCLUSION WA% rather than air trapping or centrilobular prominence may be associated with the airway hyperresponsiveness that occurs in asthmatics but not in patients with EB.