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

Abstract

To evaluate the clinical significance of residual lesions in chest computed tomography (CT) findings at the end of anti-tuberculosis treatment. 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. 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. 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.