PURPOSE:To quantitatively compare computed radiography (CR) and screen-film radiography (SFR) in the detection of pneumothorax in an animal model that simulates the neonate.MATERIALS AND METHODS:Three rabbits underwent placement of 5-F catheters in the right pleural space. Eight CR and eight SFR images were obtained. Volume-controlled pneumothorax was induced by incrementally injecting 4 cm3 of air (24 cm3 total) and four CR and four SFR images were obtained after each injection. Four radiologists blindly viewed the images twice (eight readings per image, 1,600 total observations). A dichotomous yes-no score for the presence of pneumothorax was used to calculate the volume detection threshold (VDT), defined as the air volume at which 50% of the pneumothoraces can be detected. The authors plotted the likelihood of a pneumothorax against the air volume by using the confidence indicator.RESULTS:Intraobserver VDT values for CR and SFR were not significantly different.CONCLUSION:CR is as accurate as SFR in the detection of pneumothorax in this quantitative animal model.

RATIONALE AND OBJECTIVES:The feasibility of developing an animal model to simulate radiographic features of neonatal pneumothorax was investigated, and supine computed radiography (CR) and film-screen radiography (FS) images were compared. METHODS:5-Fr pigtail catheters were inserted into the right pleural space of three New Zealand white rabbits. Two CR and two FS supine images were obtained using identical technique. After serial 4-mL injections of air, one CR and one FS supine image were obtained. The images were masked and randomized, and four radiologists reviewed the images for typical signs of pneumothorax. Chest computed tomography (CT) was performed before the injection of any air and after completion of the study. RESULTS:At zero-mL air volume, radiologists did not perceive a pneumothorax. As the air volume increased, the number of signs of a pneumothorax increased; there was no significant difference between CR and FS in the number of signs of pneumothorax detected at any volume. Chest CT confirmed that there was no unexplained air leak. The volume of air injected correlated with the calculated volume from the CT. CONCLUSIONS:This induced, volume-controlled, animal model simulated the supine radiographic features of neonatal pneumothorax.