Comparison between electronic zoom and geometric magnification of clusters of microcalcifications on digital mammography

• Published in: Journal de radiologie Vol. 91; no. 9 Pt 1; pp. 879 - 883
• Main Authors: Moraux-Wallyn, M, Chaveron, C, Bachelle, F, Taieb, S, Ceugnart, L
• Format: Journal Article
• Language: French
• Published: France 01.09.2010
• Subjects: Biopsy; Breast - pathology; Breast Neoplasms - diagnostic imaging; Breast Neoplasms - pathology; Breast Neoplasms - surgery; Calcinosis - diagnostic imaging; Calcinosis - pathology; Calcinosis - surgery; Female; Follow-Up Studies; Humans; Image Processing, Computer-Assisted; Mammography - methods; Observer Variation; Radiographic Image Enhancement - methods; Radiographic Magnification - methods; Sensitivity and Specificity; Software
• ISSN: 0221-0363
• DOI: 10.1016/S0221-0363(10)70129-3

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. 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. 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. Geometric magnification remains necessary in routine clinical practice for the characterization of microcalcifications and BI-RADS classification.