Preliminary report from the World Health Organisation Chest Radiography in Epidemiological Studies project

Abstract

Childhood pneumonia is among the leading infectious causes of mortality in children younger than 5 years of age globally. Streptococcus pneumoniae (pneumococcus) is the leading infectious cause of childhood bacterial pneumonia. The diagnosis of childhood pneumonia remains a critical epidemiological task for monitoring vaccine and treatment program effectiveness. The chest radiograph remains the most readily available and common imaging modality to assess childhood pneumonia. In 1997, the World Health Organization Radiology Working Group was established to provide a consensus method for the standardized definition for the interpretation of pediatric frontal chest radiographs, for use in bacterial vaccine efficacy trials in children. The definition was not designed for use in individual patient clinical management because of its emphasis on specificity at the expense of sensitivity. These definitions and endpoint conclusions were published in 2001 and an analysis of observer variation for these conclusions using a reference library of chest radiographs was published in 2005. In response to the technical needs identified through subsequent meetings, the World Health Organization Chest Radiography in Epidemiological Studies (CRES) project was initiated and is designed to be a continuation of the World Health Organization Radiology Working Group. The aims of the World Health Organization CRES project are to clarify the definitions used in the World Health Organization defined standardized interpretation of pediatric chest radiographs in bacterial vaccine impact and pneumonia epidemiological studies, reinforce the focus on reproducible chest radiograph readings, provide training and support with World Health Organization defined standardized interpretation of chest radiographs and develop guidelines and tools for investigators and site staff to assist in obtaining high-quality chest radiographs.

Keywords: Bacterial vaccine efficacy trials; Chest radiograph; Child; Haemophilus influenzae type b; Pneumonia; Streptococcus pneumoniae; World Health Organization defined standardized interpretation.

Fig. 1

Anteroposterior radiograph cropped to the right hemithorax of a 2 month old male hospitalized with WHO-defined very severe clinical pneumonia and meningitis. Reference measurement of one posterior rib and the adjacent rib space (double-arrow a). Estimated maximum short-axis diameter of an oval-shaped dense opacity (double-arrow b)

Fig. 2

Anteroposterior radiograph cropped to the right hemithorax of a 2 month old female hospitalized with WHO-defined very severe clinical pneumonia. Reference measurement of one posterior rib and the adjacent rib space (double-arrow a). Estimated maximum short-axis diameter of a wedge-shaped dense opacity (double-arrow b)

Fig. 3

Anteroposterior chest radiograph of an 11 month old male hospitalized with WHO-defined very severe clinical pneumonia demonstrates the silhouette sign with partial loss of the right heart border in the presence of an adjacent opacity, demonstrating endpoint consolidation