Variables that minimized procedure duration were number of image acquisitions, number of patient insertions or removals from the magnet, and assistance of a breast imaging fellow-in-training. No patient-related or target-related variables impacted procedure time.

Overlap of breast tissue is a frequent consequence of the necessary positioning and compression of the three-dimensional breast to obtain two-dimensional mammograms. The mammary glands contain fewer anatomically fixed landmarks than solid organs do; thus, variability in positioning can have an even greater effect on mammography than it has on other imaging examinations. Most often, areas of overlapping fibroglandular tissue, also known as summation shadows, are seen on only one of the two standard mammographic views. While striving to detect breast cancer as early as possible, radiologists must learn to visually compensate for apparent abnormalities in the breast that are produced by such tissue overlap. Mammographic interpretation in this setting is made even more challenging by the fact that the only manifestation of breast cancer might be a subtle change on a single mammographic view. Breast cancer might be obscured on one of the two standard views because of the density of surrounding breast tissue, mammographic technique, lesion size or location within the breast, histopathologic characteristics of the tumor, or lack of effect by the tumor on the appearance of surrounding tissues. To heighten awareness of the factors that can lead to either unnecessary recalls or failure to identify breast cancer, cases are reviewed in which false-positive findings and breast cancers were visible on only one mammographic view. Strategies for interpreting screening mammograms and determining which findings merit diagnostic evaluation are outlined so as to help minimize false-positive findings and aid in cancer detection.

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To evaluate imaging and histopathologic differences between screen-detected benign and malignant upgraded lesions initially assessed as BI-RADS 3 at diagnostic evaluation. An IRB approved retrospective review of the mammography data base from January 1, 2004 to December 31, 2008 identified 1,188 (1.07%) of 110,776 screening examinations assessed as BI-RADS 3 following diagnostic evaluation at our academic center (staffed by breast specialists) or our outpatient center (staffed by general radiologists), 1,017 with at least 24 months follow-up or biopsy. Sixty (5.9%) BI-RADS 3 lesions were upgraded to BI-RADS 4 or 5 during imaging surveillance (study population). Prospective reports, patient demographics, and clinical outcomes were abstracted from the longitudinal medical record. Mean patient age was 54.1 years (range 35-85). Lesions consisted of 7 masses, 12 focal asymmetries and 41 calcifications. Fifteen (25%) of 60 lesions upgraded from initial BI-RADS 3 assessment were malignant (1.47% of total; 15/1,017 BI-RADS 3 studies). Malignancy rates by upgraded lesion type showed no significant difference: Thirty-three (73.3%) of 45 benign upgraded lesions were calcifications compared to 8 (53.3%) of 15 malignant upgraded lesions (p = 0.202). Twelve (26.7%) of 45 benign upgraded lesions were masses or focal asymmetries, compared to 7 (46.7%) of 15 upgraded malignant lesions (p = 0.202). Six (85.7%) of 7 malignant upgraded masses/focal asymmetries had no US correlate at initial BI-RADS 3 assessment compared to 7 (58.3%) of 12 benign upgraded masses/focal asymmetries (p = 0.33). Breast-imaging specialists interpreted 21 studies, 3 (14.3%) malignant; general radiologists interpreted 39 studies, 12 (30.8%) malignant (p = 0.218). There was no significant difference in malignancy rate among different types of upgraded mammographic lesions, nor depending on subspecialty interpretation versus nonsubspecialist interpretation. Although calcifications made up a majority of upgraded lesions, most were benign, suggesting that decreased surveillance of calcifications may be appropriate.