Digital radiographic measurement of the main bronchi: a pilot study

Abstract

Conventional chest radiographs do not afford consistently good visualisation of the main bronchi and sub-carinal angle. Improved visualisation would facilitate accurate measurement of the airways, definition of normal radiographic anatomy and, possibly, earlier identification of extrinsic compression or displacement. The main objective of this study was to establish whether the paediatric main bronchi and sub-carinal angle could be measured consistently on AP supine chest images obtained using a specific digital radiographic system (DRS). The proximal bronchial diameters were measured on supine DRS chest images of 102 children between the ages of 6 months and 13 years. The left and right main bronchi could be seen clearly and measured in over 90% of cases, with intraclass correlation co-efficients of reliability indicating high intra- and inter-observer agreement. The sub-carinal angle had lower intra- and inter-observer agreement. Supine chest images acquired using DRS facilitate accurate measurement of the main bronchi and sub-carinal angle in children. Further work is required to establish population-specific age-related norms for bronchial dimensions. These could serve as reference standards for early detection of deviations from normal.