Pulmonary abnormalities on high-resolution CT demonstrate more rapid decline than FEV1 in adults with cystic fibrosis.

BACKGROUND: FEV1 may remain stable while high-resolution CT (HRCT) appearances deteriorate in children with cystic fibrosis (CF). However, spirometry results commonly decline in older age groups.
OBJECTIVES: To compare the rate of decline in HRCT abnormalities and spirometry results over time in an adult cohort with CF.
METHODS: The HRCT scans of 39 consecutive patients (19 males and 20 females; mean age, 22 years; range, 16 to 48 years) with two HRCT scans > 18 months apart were randomly and blindly scored using a modified Bhalla scoring system by two independent chest radiologists. Age, body mass index, spirometry, and sputum cultures were recorded at the time of both HRCTs. Rates of change in clinical parameters and HRCT abnormalities were calculated and compared using repeated-measures analysis of variance.
RESULTS: Mean FEV1 declined at a rate of - 2.3% per year, while mean HRCT total score declined at a rate of -2.7% per year. Several individual HRCT abnormalities as well as HRCT total scores declined significantly faster than FEV1 (p < 0.001). Six patients showed stable spirometry results but worsening HRCT scores. Mucus plugging and extent of bronchiectasis deteriorated at a more rapid rate in the group with mildly impaired lung function. Air trapping, collapse/consolidation, peribronchial thickening, severity of bronchiectasis, and generations of bronchial divisions involved deteriorated at a more rapid rate in the group with moderate-to-severely impaired lung function.
CONCLUSIONS: Adult CF patients have more rapid rates of decline in HRCT abnormalities than in spirometry results. Individual HRCT abnormalities decline at different rates depending on the degree of lung function impairment.