Relation between smear positivity and imaging findings in children with pulmonary tuberculosis

Objective/background: We investigated the relationship between high-resolution computed tomography (HRCT) imaging manifestation of tuberculosis (TB) in childhood and the results of sputum smear. The aim of this study was to identify an alternative indicator of infectivity to prevent disease transmission through special isolation methods in children who have a clinical condition that suggests TB.Methods: This retrospective comparative study was performed on 95 children under the age of 15 years with a diagnosis of TB based on World Health Organization criteria and laboratory data (smear and culture positive for Mycobacterium tuberculosis). Investigations were performed on children admitted to the National Research Institute of Tuberculosis and Lung Disease for detection of TB between 2008 and 2012. Samples were collected from direct smear or gastric lavage method. We also performed HRCT on all of the children. The children were divided into two groups based on the results of their smear test. A multivariate analytical model was used for comparison of HRCT abnormalities in these two groups.Results: Consolidation, tree-in-bud pattern, upper lobe nodular infiltration, and cavitation were the most prevalent findings in the positive smear group. Lymphadenopathy, consolidation, collapse, and nodular infiltration in the upper lobe were dominant in the negative smear group.Conclusion: We found an association between cavity, tree-in-bud, and upper lobe nodular infiltration, and smear positivity in children with TB. Furthermore, we also found an association between lymphadenopathy and collapse in the negative smear group. Moreover, the positive smear group had radiologic manifestation of postprimary TB, whereas the negative smear group had primary TB manifestation