Improved detection of lung nodules by using a temporal subtraction technique.
OBJECTIVE
To evaluate the effect of a temporal subtraction technique for digital chest radiography with regard to the accuracy of detection of lung nodules.


METHODS
Twenty solitary lung nodules smaller than 30 mm in diameter, including 10 lung cancers and 10 benign nodules, were used. The nodules were grouped subjectively according to their subtlety. For non-nodular cases, 20 nodules without perceptible interval changes were selected. All chest radiographs were obtained by using a computed radiographic system, and temporal subtraction images were produced by using a program developed at the University of Chicago. The effect of the temporal subtraction image was evaluated by using an observer performance study, with use of receiver operating characteristic analysis.


RESULTS
Observer performance with temporal subtraction images was substantially improved (A(z) = 0.980 and 0.958), as compared with that without temporal subtraction images (A(z) = 0.920 and 0.825) for the certified radiologists and radiology residents, respectively. The temporal subtraction technique clearly improved diagnostic accuracy for detecting lung nodules, especially subtle cases.


CONCLUSIONS
The temporal subtraction technique is useful for improving detection accuracy for peripheral lung nodules on digital chest radiographs.
Kakeda
Shingo
S
Department of Radiology, University of Occupational and Environmental Health School of Medicine, Iseigaoka 1-1, Yahatanisi-ku, Kitakyushu-shi 807-8555, Japan. kakeda@med.uoeh-u.ac.jp
Nakamura
Katsumi
K
Kamada
Koji
K
Watanabe
Hideyuki
H
Nakata
Hajime
H
Katsuragawa
Shigehiko
S
Doi
Kunio
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D013382:Subtraction Technique