Detection of pulmonary edema in pigs: storage phosphor versus amorphous selenium-based flat-panel-detector radiography.
OBJECTIVE
To compare diagnostic accuracy of soft-copy selenium-based digital radiographic images and soft-copy computed radiographic images obtained for detection of pulmonary edema in pigs.


METHODS
Oleic acid was injected intraatrially into three pigs (weight, 20-25 kg) at doses of 0.04, 0.05, and 0.06 mL/kg to induce pulmonary edema. Thirty-seven sets of computed radiographic, digital radiographic, and thin-section computed tomographic (CT) scans were obtained every 20-30 minutes in three pigs over 4-6 hours. Images were masked for identity, randomly sorted, and displayed on a monitor. Four radiologists rated each image for presence of parenchymal opacities by using a dichotomous scoring system in two sessions. Presence of pulmonary edema was determined with thin-section CT and a severity scale. Intra- and interobserver variations were determined with the kappa statistic and the Z test and with the Cochran Q test and the McNemar test, respectively. True-positive, true-negative, false-positive, and false-negative rates were determined. McNemar test was used to determine statistical significance of differences in detection between computed and digital radiographic images.


RESULTS
There was no significant intra- or interobserver variation, except for one pair of observers during the first interpretative session with computed radiographic images (P =.016, McNemar test). Overall sensitivity (92.1%) and diagnostic accuracy (90.2%) of digital radiography were significantly higher than those of computed radiography (79.6% and 83.4%, respectively) (P <.001 for sensitivity, P =.01 for diagnostic accuracy, McNemar test). In detection of minimal and mild pulmonary edema, sensitivity of digital radiography (84%) was significantly higher than that of computed radiography (58%) (P <.001).


CONCLUSIONS
Soft-copy digital radiographic images are superior to soft-copy computed radiographic images obtained for detection of mild pulmonary edema in pigs.
Kim
Tae Sung
TS
Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Im
Jung-Gi
JG
Goo
Jin Mo
JM
Lee
Kyoung Ho
KH
Lee
Yu-Jin
YJ
Kim
Se Hyung
SH
Kim
Seonwoo
S
D000818:Animals; D015588:Observer Variation; D019301:Oleic Acid; D011654:Pulmonary Edema / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D013902:Radiography, Thoracic / Q000295:instrumentation*; D015203:Reproducibility of Results; D012643:Selenium; D012680:Sensitivity and Specificity; D013552:Swine; D014057:Tomography, X-Ray Computed; D014963:X-Ray Intensifying Screens
D019301:Oleic Acid; D012643:Selenium