MDCT abnormalities of small- and medium-sized bronchus in active tuberculosis: a new angle on an old disease

The incidence and findings of tuberculous invasion of the peripheral bronchus have not been fully investigated with MDCT. Purpose To evaluate the prevalence and findings of MDCT abnormalities of small- and medium-sized bronchus (SMB) in active pulmonary tuberculosis (TB).

Using multiplanar reformation, 35 consecutive MDCT scans (follow-up exams available in 14 patients with a mean interval of 8.1 months) were assessed for following abnormalities of SMB: bronchial impaction (BI), wall thickening, dilatation, peribronchial cuff of soft tissue, and bronchocavitary fistula. It was also assessed whether tree-in-buds (TIB) have a tendency to distribute in the territories of diseased SMB, and whether SMB abnormalities are present in patients with relatively mild disease.

SMB abnormalities were observed in 23 (65.7%) patients with active TB. The most frequent finding was wall thickening (n = 18, 51.4%), followed by BI (n = 13, 37.1%; zigzag-shaped in four), dilatation (n = 11, 31.4%), amputated appearance of air column (n = 11, 31.4%), peribronchial cuff of soft tissue (n = 10, 28.6%), and bronchocavitary fistula (n =8, 22.9%). TIB (n = 29; absent in two patients with SMB) was mainly within (n = 14) or close to (n = 4) the territory of diseased SMB. Follow-up CT frequently showed improvement of wall thickening (11/12) and persistence of bronchial dilatation (11/13). SMB abnormality was present in all of six patients with mild disease.

MDCT shows that tuberculous invasion of the peripheral bronchus may be more frequent than previously thought, of which findings include wall thickening, BI, dilatation, amputated appearance of air column, peribronchial cuff of soft tissue and bronchocavitary fistula.