Low-dose, dynamic, expiratory thin-section CT of the lungs using a spiral CT scanner

Seventeen patients with lung transplants were evaluated with inspiratory, p ostexpiratory, and low-dose, dynamic expiratory thin-section computed tomog raphy (CT). Region of interest measurements were performed on inspiration a nd expiration images with both techniques, and mean lung attenuation change s between inspiration and expiration images were calculated and compared. D ynamic expiratory thin-section CT resulted in a significantly greater incre ase in lung attenuation than postexpiratory thin-section CT. Dynamic expira tory thin-section CT may prove useful in the evaluation of patients with lu ng diseases characterized by air flow obstruction with little increase in p atient radiation dose.