Iademarco, Michael F.

Lönnroth, Knut

O'Grady, Justin

English

Michael F. Iademarco

Justin O'Grady

Knut Lönnroth

Crossref

The International Journal of Tuberculosis and Lung Disease

Chest radiography for tuberculosis screening is back on the agenda [Editorial]

University of East Anglia digital repository

INT J TUBERC LUNG DIS 16(11):1421–1422© 2012 The Unionhttp://dx.doi.org/10.5588/ijtld.12.0774EDITORIALChest radiography for tuberculosis screening is back on the agendaTO SOME, the title may seem overstated and to oth-ers perhaps ironic, from a total lung health perspec-tive. In 1974, following similar policy changes in many countries, the World Health Organization (WHO) Committee on Tuberculosis concluded that case fi nd-ing by mass screening using chest radiography should be abandoned.1 The WHO Committee placed a strong emphasis on pursuing a diagnosis among symptom-atic patients by sputum smear microscopy because chest radiography could not be used independently for diagnosis and was too expensive. Even after such recommendations, and although it was often criticized over the decades for its insuffi cient specifi city and sen-sitivity, the use of chest radiography was maintained in clinical practice, including in many low-resource country settings, as part of the diagnostic algorithm.Chest radiography screening has been used for prevalence surveys, and more recently it has been re-vived using targeted approaches among high-risk populations. Its importance is being recognized again, including in persons infected with the human immuno-defi ciency virus and in children with tuberculosis. As early as 1992, the WHO’s Essential Technologies group made recommendations that stressed the role of and access to chest radiographs (and ultrasound) at the primary referral level.2 With the advent of dig-ital technology, the operational and expense barriers are declining for radiography as they are with myco-bacterial culture, including in low-resource countries. In 2006, the International Standards for Tuberculosis Care carefully defi ned the role of chest radiography in a clinical context,3 and the International Union Against Tuberculosis and Lung Disease has also been active in this area.* The use of mobile digital technol-ogy, dedicated expertise, and emerging techniques for computer-aided reading may help address the chal-lenges with observer error and experience.4In this issue of the Journal, Story and colleagues measured the accuracy of digital chest radiography (using state-of-the-art, low-dose equipment) on a mo-bile unit for screening high-risk urban populations in a low-incidence, high-resource setting.5 The excellent performance of the mobile unit radiography in this study is probably derived from the targeted screening of a high-risk population, a discriminatory categori-zation of radiographic interpretations, and readings done by one of two well-trained radiographers (what in other contexts might be termed ‘radiologic techni-cians’ or, in prevalence surveys, ‘fi eld readers’). It should be noted that the categorization data in Ta-ble 1 comes from the radiographers’ immediate, on-the-spot readings. Not part of the study, radiologists provided a second reading later, for the purposes of quality assurance. A live teleradiology system was not used. Limitations of the study include the fact that patients with radiographic results negative for active tuberculosis in this hard-to-reach group were not examined by culture and are less likely to seek further medical attention; the sensitivity may therefore be overestimated. It should be noted that the very high specifi city achieved is infl uenced by using a dis-crete radiographic category for active tuberculosis. More inclusive criteria for positive screening, such as further testing people with any type of abnormality, would typically lead to a higher sensitivity and lower specifi city.6 Regardless, this article provides important data from a large cohort merging two sizable program-matic databases that are very valuable from a practi-cal public health survey perspective. It is important to note the substantive benefi ts of using this targeted screening approach among a diverse population that faces many barriers to accessing medical services. This service in London is helping to control the spread of tuberculosis, the prevalence of which continues to rise annually in the city. A recent meta-analysis that demonstrated very high tuberculosis prevalence in homeless people, but with large heterogeneity across settings, argued for the need for local surveys.7 The Find and Treat mobile unit service provides the quan-titative evidence base to justify making this public health intervention a priority in London. This analysis also provides important information as interest in chest radiography re-emerges in various international settings for active case-fi nding interven-tions, the emphasis on the practical approach to lung health framework (termed ‘PAL’), and the possible critical role radiography may play in tuberculosis screening and diagnostic algorithms that use rapid molecular or point-of-care testing.8 Accordingly, the WHO has commissioned a systematic review on the accuracy of screening chest radiography, to inform our understanding about the optimal use of radiography in combination with our expanding diagnostic options. It will contribute data to a planned WHO guideline on screening for active tuberculosis. Furthermore, the Journal plans on publishing a state-of-the-art series on tuberculosis screening next year where the impor-tance of chest radiography will be highlighted.* http://www.theunion.org/index.php/en/what-we-do/tuberculosis/cxr-chest-radiographs, accessed September 20121422 The  International  Journal  of  Tuberculosis  and  Lung  DiseaseDisclaimer: The views here are of the authors and do not necessar-ily represent the views of the Centers for Disease Control and Pre-vention or the World Health Organization.Michael F. Iademarco*Justin O’Grady†Knut Lönnroth‡ *Division of Tuberculosis EliminationCenters for Disease Control and PreventionAtlanta, Georgia, USA† Centre for Clinical MicrobiologyUniversity College LondonLondon, UK‡ Stop TB DepartmentWorld Health OrganizationGeneva, Switzerlande-mail: miademarco@cdc.gov j.ogrady@ucl.ac.uklonnrothk@who.intReferences1 World Health Organization. WHO Expert Committee on Tu-berculosis, ninth report. Technical Report Series no. 552. Ge-neva, Switzerland: WHO, 1974.2 World Health Organization. WHO Study Group on the func-tions of hospitals at the fi rst referral level. The hospital in rural and urban districts. Technical Report Series no. 819. Geneva, Switzerland: WHO, 1992.3 Hopewell P C, Pai M, Maher D, Uplekar M, Raviglione M C. International standards for tuberculosis care. Lancet Infect Dis 2006; 6: 710–725. 4 Koppaka R, Bock N. How reliable is chest radiography? In: Frieden T, ed. Toman’s tuberculosis. Geneva, Switzerland: World Health Organization, 2004.5 Story A, Aldridge R W, Abubakar I, et al. Active case fi nding for pulmonary tuberculosis using mobile digital chest radiography: an observational study. Int J Tuberc Lung Dis 2012; 16: 1461–1467. 6 World Health Organization. Tuberculosis prevalence surveys: a handbook. WHO/HTM/TB/2010.17. Geneva, Switzerland: WHO, 2011.7 Beijer U, Wolf A, Fazel S. Prevalence of tuberculosis, hepatitis C virus, and HIV in homeless people: a systematic review and meta-analysis. Lancet Infect Dis 2012; August 17. [epub ahead of print]8 World Health Organization. Rapid implementation of the Xpert MTB/RIF diagnostic test. Technical and operational ‘how-to’. Practical considerations. WHO/HTM/TB/2011.2. Geneva, Swit-zerland: WHO, 2011.

Chest radiography for tuberculosis screening is back on the agenda

Chest Radiography for Tuberculosis Screening is Back on the Agenda

Chest Radiography for Tuberculosis Screening is Back on the Agenda

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