High-resolution CT features of severe asthma and bronchiolitis obliterans.

AIM

To evaluate the high-resolution CT findings of severe asthma (SA) and bronchiolitis obliterans (BO) and determine whether any reliable discriminating HRCT features exist.

MATERIALS AND METHODS

HRCT examinations of the chest of 30 patients with SA and 14 patients with BO were analysed. Images were scored for the presence and extent of 21 CT findings.

RESULTS

The most consistent HRCT features in SA were bronchial wall thickening in 30 (100%), expiratory air trapping in 19 of 22 examinations with expiratory images (87%), inspiratory decreased attenuation in 18 (60%), and bronchial luminal narrowing in 12 (40%). The most consistent HRCT features in BO were expiratory air trapping in 10 of 10 examinations with expiratory images (100%), bronchial wall thickening in 13 (93%), inspiratory decreased attenuation in 11 (79%), ground glass opacity in seven (50%), and mosaic pattern of attenuation in seven (50%). Decreased attenuation was more extensive in BO than in SA on both inspiratory and expiratory images. The mosaic pattern of attenuation was present in seven (50%) BO patients but in only one (3%) SA patients (P=0.0006).

CONCLUSIONS

Mosaic pattern of attenuation, when present, is highly suggestive of BO, but SA and BO may be indistinguishable.