1 INTRODUCTION
Bronchiolitis obliterans (BO) is a chronic obstructive lung disease that
leads to the irreversible obliteration of the small
airways1,2. BO can occur with various etiologic
factors, including infection, allogeneic hematopoietic stem cell
transplantation (HSCT), and organ transplantation3.
Bronchiolar epithelial cell and subepithelial structural damage and
inflammation are the major pathogenesis of BO4.
Early diagnosis of BO in young children is particularly important, as it
affects permanent lung function in the future. The diagnosis of BO is
generally based on chest computed tomography (CT) images, along with a
combination of PFTs or histologic findings. Common CT findings in
patients with BO include bronchiectasis, bronchial wall thickening, and
air trapping5. Conventionally, spirometry and chest CT
findings have been suggested as the two most important standards for the
diagnosis of BO. However, a clear diagnosis or assessment of the
severity of early childhood BO can often be challenging, as the presence
of lumen dilatation and bronchial wall thickening may be discrete or
absent in the early stages, and poor coordination often makes PFTs
difficult to complete. Hence, it is desirable to develop additional
tools that can improve the diagnosis of BO among young children.
The purpose of this study was to evaluate the quantitative diagnostic
performance of CT in pediatric BO patients by analyzing various lung
density indices (LDIs) based on mean lung density (MLD) measured during
inspiration and exhalation using the chest CT quantitative method.