High resolution computed tomography in sarcoidosis and extrinsic allergic alveolitis: imaging insights.

Chest radiography gives a useful but imprecise indication of the extent of diffuse lung disease. The limitations in sensitivity and specificity of chest radiography in this context are well known and have been reinforced with the advent of computed tomography and its application to this difficult diagnostic area. High resolution computed tomography shows morphological detail invisible on chest radiography and both sensitivity and specificity in diffuse lung disease are greatly improved with this technique. Features of sarcoidosis and extrinsic allergic alveolitis revealed by high resolution computed tomography are examined in this review.