Clinical significance of residual lesions in chest computed tomography after anti-tuberculosis treatment

Abstract

OBJECTIVE: To evaluate the clinical significance of residual lesions in chest computed tomography (CT) findings at the end of anti-tuberculosis treatment. METHODS: We retrospectively reviewed 66 newly diagnosed patients with pulmonary tuberculosis (PTB) who were proven bacteriologically and/or histologically between March 2009 and December 2011. All patients were treated with standard short-course chemotherapy. Chest CT scans were performed before and after treatment. We assessed the residual lesions according to the response to treatment: possible active, equivocal and no active lesions. RESULTS: The most common CT finding before anti-tuberculosis treatment was bronchogenic spreading inflammation, such as the tree-in-bud appearance. After completion of anti-tuberculosis treatment, regression of the initial parenchymal findings was found in all types of PTB lesions except consolidations. According to the treatment response, 33 (50%) patients had possible active lesions, 5 (8%) had equivocal lesions and 28 (42%) had no active lesions. However, no lesions progressed during a median follow-up of 15 months (interquartile range 10-21 months) after treatment completion, and no patient relapsed during this period. CONCLUSIONS: If initial parenchymal lesions regressed after sufficient TB treatment, residual lesions were not suggestive of persistent activity or the possibility of early relapse of PTB.