Comparison of diagnostic accuracy of breast masses using digitized images versus screen-film mammography.
BACKGROUND
Medical film digitizers play an important transitory role as digital-analogue bridges in radiology. Digitized mammograms require evaluation of performance to assure medical image quality.


OBJECTIVE
To compare the diagnostic accuracy in the interpretation of breast masses using original screen-film mammograms versus digitized images.


METHODS
A total of 72 female patients between 55 and 81 years of age suspected of having breast cancer were selected by two non-observing radiologists. Of these, 31 cases were benign lesions and 41 cases were cancer. The mammography films were digitized using a laser film digitizer. Three radiologists, each with more than 10 years of experience in mammography, interpreted the screen-film mammograms and digitized images respectively. The time interval was 4 weeks. A four-point malignancy scale was used, with 1 defined as definitely not malignant, 2 as probably not malignant, 3 as probably malignant, and 4 as definitely malignant. Receiver operating characteristic (ROC) curves, sensitivity, and specificity were compared.


RESULTS
The average area-under-the-curve (Az) value of the original screen-film mammograms was 0.921, and the average Az value of the digitized images was 0.859. This difference was not statistically significant (P=0.131). The detection specificity of extremely dense breasts was lower than that for other breast compositions for both digitized images and screen-film mammograms. No statistical significance in sensitivity and specificity was observed between digitized images and mammograms for each breast composition. Original screen-film mammograms were observed to perform better than digitized images.


CONCLUSIONS
Digitized images with a spatial resolution of 175 microm can be used instead of screen-film mammograms in the diagnosis of breast cancer.
Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China.
Zhigang
Z
Liang
Xiangying
X
Du
Jiabin
J
Liu
Xinyu
X
Yao
Yanhui
Y
Yang
Kuncheng
K
Li
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008327:Mammography / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014963:X-Ray Intensifying Screens