Functional significance of the decreased attenuation sign on expiratory CTin pulmonary sarcoidosis - Report of four cases

We describe four patients with proven sarcoidosis and minor pulmonary invol vement according to high-resolution CT (HRCT) findings in whom the recently described sign of decreased attenuation on expiratory HRCT scan appeared a ssociated with the reduction of the single-breath diffusing capacity of the lung for carbon monoxide (DLCO) and the DLCO adjusted for alveolar volume. These alterations were, in part, reversible under steroid treatment. Major indexes of airway obstruction (FEV1/vital capacity ratio and FEV1) were no rmal, while the maximum expiratory flow at 25% above the residual volume of FVC was reduced. These observations suggest that an expiratory HRCT mosaic pattern and diffusion impairment may be early findings in pulmonary sarcoi dosis and may be useful for its detection and follow-up.