In this issue of the Journal, Jiménez et al describe a new technique in high resolution computed tomography (HRCT) of the chest in children with cystic fibrosis (CF).¹ HRCT is widely available to clinicians who care for children with CF; it has some advantages over plain chest radiography but exposes the child to more radiation. The HRCT technique described by Jiménez et al reduces the radiation exposure by limiting the number of slices to six. Will six slices be sufficient to provide the information that the clinician seeks?

Pulmonary disease in children with CF is characterised by impaired clearance of pathogens, resulting in intermittent and later permanent infection of the lower respiratory tract, with bacterial and fungal pathogens causing progressive mucous impaction and bronchiectasis. Asymptomatic infants with CF have been shown to have abnormalities in pulmonary function^2,3 and to have airway inflammation on lavage studies.^4,5 Plain chest radiographs traditionally have been the mainstay of radiological assessment to detect collapse, consolidation, peribronchial thickening, patches of fibrosis, and cystic change. Several scoring systems based on these changes have been developed and are used for annual data collection and within national databases,^6,7,8,9,10 and show low interobserver variability and good correlation with lung function and infective exacerbation rate in older children.¹¹ The current North American Cystic Fibrosis Foundation guideline¹² and the European Consensus on CF standards of care recommend an annual plain chest radiograph, the latter recommending use of the Northern score (to limit the radiograph to a single posterior–anterior view).^10,13

High resolution computed tomography of the chest has the ability to detect abnormalities in the airway and lung parenchyma including air trapping, mucoid impaction, and bronchiectasis that …