False-negative findings of malignant breast lesions on preoperative magnetic resonance mammography.

The aim of this study was to evaluate causes and percentages of false negative diagnoses of malignant breast lesions on preoperative dynamic magnetic resonance mammography (MRM). MRM was performed in 223 patients with 234 histopathologically proven malignant breast lesions (193 invasive carcinoma, 41 CIS) which were analyzed prospectively by routine analysis prior to surgery and re-analyzed by specialists, retrospectively. False negative findings were re-evaluated with respect to contrast enhancement, size and shape of lesions, reading errors, and technical problems. Preoperative analysis missed 27 of 234 malignant breast lesions (sensitivity 88.5%) including 15 of 193 invasive cancers (sensitivity 92%) and 12 of 41 CIS (sensitivity 71%). Five of 193 invasive cancers (four invasive lobular, one invasive tubular carcinoma) and five of 41 CIS lesions were missed due to delayed or no contrast enhancement. The remaining 17 false negative diagnoses were due to reading errors (n=8), previous core biopsies (n=3), metal induced artefacts (n=3), localization outside the field of view (n=1), incorrect injection (n=1) or movement artefacts (n=1). Using dynamic MR mammography, there were 4.3% slow contrast enhancing malignant breast lesions and a maximum sensitivity of 95.7% for detection of all malignant breast lesions (97.4% for invasive breast cancer, 87.8% for carcinoma in situ) can be achieved in a preselected preoperative population.