ROC analysis of detection of metastatic pulmonary nodules on digital chest radiographs with temporal subtraction.
OBJECTIVE
The authors' purpose was to evaluate the effect of temporal subtraction on digital chest radiographs in the detection of metastatic pulmonary nodules.


METHODS
The study included 21 cases with metastatic pulmonary nodule and 21 cases without metastatic nodule. Eleven radiologists, including eight residents and three certified radiologists, provided their confidence levels for the presence or absence of pulmonary nodules without and with temporal subtraction. Their performances without and with temporal subtraction were evaluated by means of receiver operating characteristic analysis with both independent and sequential tests.


RESULTS
For the independent test, the radiologists' Az (area under the receiver operating characteristic curve) values were 0.871 without and 0.954 with temporal subtraction, compared with 0.882 and 0.955, respectively, for the sequential test. Diagnosis accuracy was significantly improved with the use of temporal subtraction. There was no significant difference in Az values between the independent and sequential tests.


CONCLUSIONS
Temporal subtraction is useful in the detection of metastatic pulmonary nodules, and this technique augments the value of digital chest radiography.
Uozumi
T
T
Department of Radiology, University of Occupational and Environmental Health School of Medicine, Kitakyushu-shi, Japan.
Nakamura
K
K
Watanabe
H
H
Nakata
H
H
Katsuragawa
S
S
Doi
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D013382:Subtraction Technique