HomeA chest x-ray is required for the initial evaluation of children with suspected intrathoracic TB.41 In addition to an anterior-posterior view, a lateral radiograph is recommended to assess for hilar and mediastinal lymphadenopathy, the most frequent radiologic manifestations of intrathoracic TB in children.42,43 Good-quality chest x-rays in children are essential because the common radiologic manifestations are more subtle than in adult-type disease and often located proximally to other structures in the mediastinum. This requires optimal positioning and cooperation of the child to avoid rotational and motion artifacts. Repeating chest x-rays with better positioning and inspiration may clarify questionable abnormalities and are always encouraged if the initial images are of suboptimal quality. Interpretation by a radiologist with experience in pediatric TB is important; there is a high level of inter-reader and intra-reader variability for detecting lymphadenopathy.44,45 Computer-aided detection to improve the sensitivity of radiographs is an area of active research but not available in most settings at this time.46,47
Children are more susceptible to the long-term effects of the increased radiation exposure from computed tomography (CT) for intrathoracic disease.48–51 The risk/benefits of CT scans and their impact on patient management should be assessed on a case-by-case basis. In general, we would only consider a chest CT in a child in very limited circumstances and only in children who have an abnormal initial chest x-ray. These may include diagnostic uncertainty in an ill child, a questionable radiograph in a child in contact with drug-resistant TB and planning for future diagnostic procedures. In adolescents with pulmonary disease, rapidly obtaining sputum for AFB smear and culture may reduce unnecessary CTs.49 For extra-thoracic TB diagnosis, imaging should be performed according to clinical signs and symptoms, where the optimal modality is site specific (see Chapter 7: Extra-pulmonary Tuberculosis). However, for young children, considerations include the need for sedation, the ability of the child to cooperate and the risks of additional radiation exposure. For abdominal and lymph node TB, ultrasound is effective and as sensitive as CT.52,53 CT may be more helpful in differentiating abdominal TB from other noninfectious pathologies.54 For bone and joint TB, magnetic resonance imaging (MRI) is helpful in distinguishing osteoarticular from soft-tissue lesions. CNS TB is a significant concern in young children, who frequently present with hydrocephalus. Contrast enhancement is essential in identifying leptomeningeal enhancement and MRI is better at identifying both leptomeningeal enhancement and characteristic parenchymal disease (tuberculoma) than CT.55,56 Finally, newer modalities such as positron emission tomography (PET)/CT scans may have a role in select cases of extra-pulmonary TB where available. They have the advantage of being quick (without need for heavy sedation) and can identify multiple sites of disease.57
Good practice statement
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Good quality anterior-posterior and lateral chest x-rays are required for the initial evaluation of TB disease in children. Computed tomography is not routinely recommended.
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