Detecting early structural lung damage in cystic fibrosis.

In cystic fibrosis (CF) patients, both severe lung inflammation and severe lung damage occur early and persist throughout life. High-resolution computed tomography (HRCT), a more sensitive method of detecting structural abnormalities than chest X-ray, shows that airways undergo substantial thickening in early CF lung disease. Lung function tests, which are an indirect measure of structural integrity, are insensitive to localized or early damage. Thickening of the peripheral airways causes a reduction in maximal expiratory flow at 25% of forced vital capacity (MEF(25)) or other measurements of peripheral air flow. Reduced peripheral flows, even in the presence of normal forced expired volume in 1 sec (FEV(1)) and forced vital capacity (FVC), should be considered an early sign of substantial lung damage and should stimulate aggressive treatment to prevent further deterioration.