[Comparison between electronic zoom and geometric magnification of clusters of microcalcifications on digital mammography].
OBJECTIVE
With the advent of digital mammography with electronic zoom capabilities, we have sought to determine the need for geometric magnification for the evaluation of clusters of microcalcifications.


METHODS
Eighty-eight clusters of microcalcifications were reviewed by two experienced radiologists using electronic zoom (ZOOM) and geometric magnification (MAG). The following criteria were evaluated: image quality, shape and number of microcalcifications, size and shape of the clusters. The clusters were classified based on malignancy risk using the BI-RADS criteria. Histological results from macrobiopsy or surgery as well as 2 year follow-up were used as reference for statistical analysis.


RESULTS
Sensitivity (100% for MAG and 90% for ZOOM), specificity (52% versus 39%), positive predictive value (51% versus 44%) and negative predictive value (100% versus 88%) were superior for geometric magnification compared to electronic zoom irrespective of the reviewer but without reaching statistical significance. However, image quality was significantly superior with geometric magnification (p<<0.05). In addition, reviewers were more confident in their interpretation of geometric magnification images.


CONCLUSIONS
Geometric magnification remains necessary in routine clinical practice for the characterization of microcalcifications and BI-RADS classification.
Moraux-Wallyn
M
M
Centre Oscar Lambret, Lille, France. mariemoraux@yahoo.fr
Chaveron
C
C
Bachelle
F
F
Taieb
S
S
Ceugnart
L
L
D001706:Biopsy; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008327:Mammography / Q000379:methods*; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D011858:Radiographic Magnification / Q000379:methods*; D012680:Sensitivity and Specificity; D012984:Software