Abstract
Aim: To determine the repeatability and the discriminate validity of gas trapping score in infants with cystic fibrosis (CF) using thoracic computed tomography imaging during normal breathing (CT-b).
Method: 41 CF infants were included with 2 CT-b respectively at 10.5 ± 1.7 and 57.5 ± 6.0 weeks old. Imagings were compared to healthy infants groups of similar age. At end expiratory level, image was acquired with 0.4 s of exposition time. Images was acquired 1 cm below the interclavicular notch, and interval between images was 5 mm for the first and 8 mm for the second CT-b. The extent of gas trapping for each of the 6 Zones (upper, mid, and lower; right and left) was graded as: absent = 0, <50% = 1; >50% = 2. Images were read in random order, on a soft copy reporting station and were analyzed twice in blind test at 6 month interval by the same pediatric thoracic radiologist. Results are express as Z-score created from our healthy control.
Results: All CT-b scan showed a good concordance between the 2 scores: ICC = 0.98 [ 0.97 , 0.99 ]. In our CF compare to healthy infants, we observed a significant increase of air trapping score expressed in Z-score, at 10 weeks (4.4 ± 5.1 vs 0.64 ± 1.0) and 13 month old (7.52 ± 9.7 vs 0.56 ± 0.7). At 10 weeks old 50 % of our CF infants and 70 % at 13 month present a Z score for air trapping higher then 1.64.
Conclusion: In a ethical context which will progressively reduces the possibility to sedate infants for lung exploration, with the constant decrease of exposition time due to technical progress, CT-b could be an alternative method without anesthesia, to evaluate presence of gas trapping in young CF infant.
- Copyright ©ERS 2015
