The natural breathing methods used in dynamic chest radiography (DCR) offer more truthful representations to reflect treatment efficacy for pulmonary exacerbations in individuals with cystic fibrosis (CF) than the artificial breathing techniques used in spirometry, according to a new study published in Radiography.

Investigators analyzed data from 20 individuals with CF admitted to Liverpool Heart and Chest Hospital in the United Kingdom with pulmonary exacerbations between December 2019 and August 2020. They assessed treatment efficacy for pulmonary exacerbations and compared improvements in pulmonary function testing using spirometry with right and left hemidiaphragm excursion during both deep and tidal breathing, mean expiratory diaphragm velocity, and projected lung area using DCR.

After spirometry, the median percentage of predicted forced expiratory volume improved after treatment from 44% to 55% (interquartile range [IQR], 23%; P =.004), while the median percentage of predicted forced vital capacity improved from 58% to 76% (IQR, 18%; P =.004).

Read more about CF testing

Following DCR, right and left hemidiaphragm excursion during deep breathing increased from a median of 18 to 25 mm (P =.03) and 13 to 19 mm (P =.03), respectively. Right and left hemidiaphragm excursion during tidal breathing improved from a median of 12 to 15 mm (P =.03) and 11 to 13 mm (P =.04), respectively.

Right and left hemidiaphragm mean expiratory diaphragm velocity increased from a median of 6 to 9 mm/sec (P =.004) and 7 to 11 mm/sec (P =.004), respectively. DCR demonstrated that the projected lung area during full expiration improved following treatment from 42±16 cm2/sec to 56±24 cm2/sec (P =.03).

“Our study gives insights into pulmonary dynamics and suggests that it may be of particular use in individuals in whom spirometry is difficult to perform,” the authors concluded. “The ability to perform DCR away from the attending clinician, thus reducing exposure to potential aerosol generation by the participant, indicates that it may be a useful technique in individuals with transmissible respiratory infections.”

Reference

FitzMaurice TS, McCann C, Nazareth DS, McNamara PS, Walshaw MJ. Use of dynamic chest radiography to assess treatment of pulmonary exacerbations in cystic fibrosis. Radiology. Published online March 15, 2022. doi:10.1148/radiol.212641