Comparison of quiet breathing and controlled ventilation in the high-resolution CT assessment of airway disease in infants with cystic fibrosis

Background: Respiratory motion and low lung volumes limit the quality of HRCT examinations in infants and young children. Objective: To assess the effects of respiratory motion and lung inflation on the ability to diagnose airway abnormalities and air trapping (AT) using HRCT in infants with cystic fibrosis (CF). Materials and methods: HRCT images of the lungs were obtained at four anatomical levels in 16 sedated children (age 2.4 +/- 1.1 years, mean +/- SD) with CF using controlled ventilation at full lung inflation (CVCT-I), at resting end exhalation (CVCT-E), and during quiet breathing (CT-B). Two blinded reviewers independently and then by consensus scored all images for the presence or absence of bronchiectasis (BE), bronchial wall thickening (BWT), and AT. Results: Of the 64 images evaluated, BE was identified in 19 (30%) of the CVCT-I images compared to 6 (9%) of the CVCT-E images (P=0.006) and 4 (6%) of the CT-B images (P=0.044). AT was seen in 29 (45%) of the CVCT-E images compared to 14 (22%) of the CVCT-I images (P=0.012) and 12 (19%) of the CT-B images (P=0.012). There were no significant differences in the detection of BWT among the three methods. Summary: In infants with CF, fully inflating the lung improved the ability to diagnose early BE, and obtaining motion-free images at end exhalation enhanced the detection of AT.