Rationale: In cystic fibrosis (CF), lung disease is the predominant cause of morbidity and mortality. Little is known about the spectrum of structural abnormalities on computed tomography (CT) scans from CF patients with severe advanced lung disease (SALD). No specific CT scoring system for SALD is available.
Objectives: To design a quantitative CT scoring system for SALD, to determine the spectrum of structural abnormalities in patients with SALD, and to correlate the SALD system with an existing scoring system for mild CF lung disease and pulmonary function tests (PFTs).
Methods: 57 CF patients contributed one CT made during screening for lung transplantation. For the SALD system, lung tissue was divided into 4 components: infection/inflammation (including bronchiectasis, airway wall thickening, mucus and consolidations) air trapping/hypoperfusion, bulla/cysts, and normal/hyperperfused tissue. The volume proportion of the components was estimated on a 0-100% scale, mean volumes for the whole lung were computed. Scores were correlated with Brody-II scores and PFTs.
Results: The SALD system identified a wide spectrum of structural abnormalities ranging from predominantly infection/inflammation to predominantly air trapping/hypoperfusion. SALD infection/inflammation scores correlated with Brody-II scores (rs 0.36 to 0.64) and SALD normal/hyperperfusion scores correlated with FEV1 (rs = 0.37). Reproducibility for both systems was good.
Conclusions: We developed a CT scoring system to characterize the structural abnormalities in patients with SALD. A wide spectrum was observed in SALD ranging from predominantly air trapping to predominantly infection/inflammation-related changes. This spectrum may have clinical implications for patients with SALD.