Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography.
OBJECTIVE
To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs.


METHODS
Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring <or=20mm and from 15 normal participants. Each dataset included standard and corresponding DES images. There were six non-solid, 10 part-solid, and 10 solid nodules. The mean size of the 26 nodules was 15+/-4.8mm. Receiver operating characteristic (ROC) analysis was performed to compare the performance of the eight board-certified radiologists.


RESULTS
For the eight radiologists, the mean value of the area under the ROC curve (AUC) without and with DES images was 0.62+/-0.05 and 0.68+/-0.05, respectively; the difference was statistically significant (p=0.02). For part-solid nodules, the difference of the mean AUC value was statistically significant (AUC=0.61+/-0.07 versus 0.69+/-0.05; p<0.01); for non-solid nodules it was not (AUC=0.62+/-0.1 versus 0.61+/-0.09; p=0.73), and for solid nodules it was not (AUC=0.75+/-0.1 versus 0.78+/-0.08; p=0.23). For nodules with overlapping bone shadows, the difference of the mean AUC value was statistically significant (p=0.03), for nodules without overlapping, it was not (p=0.26).


CONCLUSIONS
Use of a double-exposure DES technique at FPD chest radiography significantly improved the diagnostic performance of radiologists to detect small pulmonary nodules.
Oda
S
S
Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, Honjo, Kumamoto, Japan. seisei0430@nifty.com
Awai
K
K
Funama
Y
Y
Utsunomiya
D
D
Yanaga
Y
Y
Kawanaka
K
K
Nakaura
T
T
Hirai
T
T
Murakami
R
R
Nomori
H
H
Yamashita
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002983:Clinical Competence / Q000592:standards*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D018787:Radiation Oncology / Q000592:standards*; D015900:Radiography, Dual-Energy Scanned Projection / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D013382:Subtraction Technique / Q000295:instrumentation