title: Relation between smear positivity and imaging findings in children with pulmonary tuberculosis.
abstract: OBJECTIVE
  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 15years 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pediatric Respiratory Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic address: Mar_hassanzad@yahoo.com.
authors.forename: Maryam
authors.initials: M
authors.lastname: Hassanzad
authors.affiliation: Department of Pediatric Respiratory Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Bolursaz
authors.affiliation: Department of Pediatric Respiratory Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Payam
authors.initials: P
authors.lastname: Mehrian
authors.affiliation: Department of Pediatric Respiratory Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Farahnaz
authors.initials: F
authors.lastname: Aghahosseini
authors.affiliation: Department of Pediatric Respiratory Medicine, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Velayati
keywords: Children; High-resolution computed tomography; Pulmonary tuberculosis; Smear positivity