Quantitative density-time measurements in the lungs of children with suspected airway obstruction using ultrafast CT.

Fourteen children under 3 years of age with possible airway obstruction were evaluated with an ultrafast CT scanner, Imatron C-100. Serial 0.05-second multilevel scans were obtained through the chest at rates of 17 images per second. No patient sedation or contrast medium was used. Time-density curves generated over each lung and specific pulmonary zones were compared to characterize the normal variation of density during inspiration and expiration and to determine abnormal patterns associated with airway obstruction. There was a high, positive correlation value (r greater than 0.79) between time/density curves over those pulmonary regions in which there was no focal bronchial obstruction and a low, negative correlation value (r = less than -0.58) with bronchial obstruction. Three studies with reconstruction artifacts were excluded. Furthermore, the results indicate that young children generally have denser lungs, particularly in expiration, than older children or adults. This preliminary study suggests that ultrafast CT offers a promising, unique, rapid and noninvasive approach for diagnosing airway obstruction in childhood.