[Detection of microcalcifications in breast specimens by 4-fold DIMA direct magnification radiography compared to 1.5-fold conventional magnification radiography]

Abstract

Aims of study: The purpose of this study was to investigate the efficacy of 4-fold magnification breast specimen radiography (direct magnification, DIMA) compared to conventional 1.5-fold magnification radiography in evaluating the presence or absence of carcinoma at the surgical margins by detection of microcalcification.

Methods: Fifty breast specimens with non-palpable microcalcifications were examined during surgical biopsy using both DIMA (4-fold) and conventional (1.5-fold) magnification specimen radiography. The number of detected microcalcifications of the whole specimen, of an area of 5 mm distance to the margins and of the area of the suspicious cluster of microcalcifications was counted and the results compared with the histological examination as a gold standard.

Results: In 50 specimen 2821 (1305 within 3 mm distance to the margins) microcalcifications were detected with the DIMA mammography technique compared to 1608 (446) microcalcifications with the conventional technique. This increased detection rate by DIMA-magnification radiography was accompanied by a decreased specificity in comparison to the conventional magnification radiography (33.3% DIMA versus 83.3% conventional) regarding the evaluation of presence or absence of carcinoma at the surgical margins. Differentiating the microcalcifications into calcifications belonging to the suspicious cluster and those that are located outside the cluster led to an increase in specificity (83.3% DIMA versus 100% conventional).

Conclusions: The efficacy of breast specimen radiography in evaluating the presence or absence of carcinoma at the surgical margins by detection of microcalcification is not improved by 4-fold magnification radiography (direct magnification, DIMA) compared to conventional 1.5-fold magnification radiography due to an increase in false-positive results. Analysis of the attachment of the microcalcifications to the cluster can improve the specificity.