Potential usefulness of similar images in the differential diagnosis of clustered microcalcifications on mammograms.
OBJECTIVE
To evaluate the potential usefulness of images of lesions of a known disease that have a similar appearance to lesions of an unknown disease in distinguishing between benign and malignant clustered microcalcifications on mammograms by removing the unusual cases from the database.


METHODS
Institutional review board approval for this retrospective HIPAA-compliant study of images from a publicly available database was obtained. Unusual lesions, such as malignant-looking benign lesions and benign-looking malignant lesions, were removed from the database. A total of 20 benign and 20 malignant lesions were selected with a stratified randomization method, and it was these lesions that served as unknown cases in this observer study. For each unknown case, eight similar images of benign lesions and eight similar images of malignant lesions were preselected with a computerized scheme. From these preselected images, a breast radiologist subjectively selected the four most similar images of benign lesions and the four most similar images of malignant lesions. Five attending breast radiologists and three breast-imaging fellows participated in the observer study. Observers provided their confidence level regarding malignancy of the unknown case before and after they viewed the similar images. The results were evaluated with multireader multicase receiver operating characteristic (ROC) analysis.


RESULTS
For all observers, the areas under the ROC curves (AUCs) were improved when similar images were used. The average AUC for all observers increased from 0.692 without use of similar images to 0.790 with use of similar images (P = .0009).


CONCLUSIONS
The presentation of similar images can improve radiologists' performance in the differential diagnosis of clustered microcalcifications on mammograms.
Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, University of Chicago, 5841 S Maryland Ave, MC 2026, Chicago, IL 60637, USA. nakayama@clin.medic.mie-u.ac.jp
Ryohei
R
Nakayama
Hiroyuki
H
Abe
Junji
J
Shiraishi
Kunio
K
Doi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002983:Clinical Competence; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies