Computed tomography features of lung parenchymal changes in pulmonary tuberculosis.

Twenty-five patients with active pulmonary tuberculosis were prospectively studied with CT. Three major parenchymal patterns were noted. The nodular opacities pattern was seen in all cases. Confluent consolidation was seen in 37% of patients and consolidation with associated loss of volume (CWALV) was seen in 69% of patients. High-resolution CT (HRCT) features of bronchogenic spread included (i) a centrilobular nodule or a branching linear structure (92.3%); (ii) bronchial wall thickening (61.5%); (iii) a 'tree in bud' appearance (92.3%); and (iv) poorly marginated 5-8 mm nodules (61.5%). Most of the patterns showed satellite lesions in the form of small nodules or peripheral areas of increased attenuation. Cavitation was most common in CWALV lesions. Bronchiectasis was a common accompaniment (81.3%), and its occurrence paralleled the distribution of parenchymal lesions. Associated pleural thickening was noted in half the cases. To conclude, distinctive parenchymal changes were noted with CT in cases of pulmonary tuberculosis, which may suggest the diagnosis in the appropriate clinical setting.