Frequency and characteristics of pulmonary nodules in children at computed tomography

Atia Samim, Annemieke S. Littooij, Marry M. van den Heuvel-Eibrink, Frank J. Wessels, Rutger A. J. Nievelstein, Pim A. de Jong

Normative data on pulmonary nodules in children without malignancy are limited. Knowledge of the frequency and characteristics of pulmonary nodules in healthy children can influence care decisions in children with malignant disease. To provide normative data concerning the frequency and characteristics of pulmonary nodules on computed tomography (CT) in young children. All children ages 1 year-12 years who underwent chest CT after high-energy trauma were retrospectively investigated. Exclusion criteria were a history of malignancy, thick image slices, motion artefacts and extensive post-traumatic pulmonary changes. Two radiologists were asked to independently identify all nodules and to characterize each nodule with respect to location, size, perifissural location and calcification. Discrepancies were adjudicated by a third reader, who set the reference standard in this study. Interobserver agreement in detection and characterization was assessed using the kappa coefficient (κ). Identified were 120 patients, of whom 72 (75% male; median age: 8.0 years [interquartile range: 4-11]) were included. A total of 59 pulmonary nodules were present in 27 patients (38%; 95% confidence interval: 26-49%; range: 1-5 nodules per patient, with a mean diameter of 3.2 mm [standard deviation: 0.9 mm]). For nodule detection, the per-patient interobserver agreement was substantial (κ=0.78) and per-lobe agreement was moderate (κ=0.40). For characterization, there was fair to substantial agreement (κ=0.36-0.74). Small pulmonary nodules on chest CT are a common finding in otherwise healthy children, but detection and characterization have only moderate interobserver agreement.