Quantitative assessment of chronic lung disease of infancy using computed tomography.

The aims of this study were to determine whether infants and toddlers with chronic lung disease of infancy (CLDI) have smaller airways and lower lung density compared with full-term healthy controls. Multi-slice computed tomography (CT) chest scans were obtained at elevated lung volumes during a brief respiratory pause in sedated infants and toddlers; 38 CLDI were compared with 39 full-term controls. For CLDI subjects, gestational age at birth ranged from 25 to 29 weeks. Airway size was measured for the trachea and the next three to four generations into the right lower lobe; lung volumes and tissue density were also measured. The relationship between airway size and airway generation differed between the CLDI and full-term groups; the sizes of the first and second airway generations were larger in the shorter CLDI than in the shorter full-term subjects. The increased size in the airways in the CLDI subjects was associated with increasing mechanical ventilation time in the neonatal period. CLDI subjects had a greater heterogeneity of lung density compared with full-term subjects. Our results indicate that quantitative analysis of multi-slice CT scans at elevated volumes provides important insights into the pulmonary pathology of infants and toddlers with CLDI.

Computed tomography score and pulmonary function in infants with chronic lung disease of infancy.

Chronic lung disease of infancy (CLDI) remains a common outcome among infants born extremely prematurely. In older children and adults with lung disease, pulmonary function and computed tomography (CT) scores are used to follow up respiratory disease and assess disease severity. For infants and toddlers, however, these outcomes have been used very infrequently and most often, a dichotomous respiratory outcome (presence or absence of CLDI) is employed. We evaluated the performance of CT score and pulmonary function to differentiate infants and toddlers with CLDI from a control group. CT scans, forced expiratory flows and pulmonary diffusing capacity were obtained in 39 CLDI patients and 41 controls (aged 4-33 months). CT scans were quantified using a scoring system, while pulmonary function was expressed as Z-scores. CT score outperformed pulmonary function in identifying those with CLDI. There were no significant correlations between CT score and pulmonary function. CT score had a better performance than pulmonary function in differentiating individuals with CLDI; however, these outcomes may reflect differing components of the pulmonary pathophysiology of CLDI. This new information on pulmonary outcomes can assist in designing studies with these parameters. Future studies will be required to evaluate which of the outcomes can better detect improvement with therapeutic intervention and/or lung growth.