Advances in Digital Breast Tomosynthesis.

OBJECTIVE: Digital breast tomosynthesis (DBT) has rapidly emerged as an important new imaging tool that reduces the masking effect of overlapping fibroglandular tissue, thereby improving breast cancer detection. This article will review key features of DBT including technique, clinical implementation, and benign and malignant imaging findings. We will also present the benefits of DBT in screening, diagnostic workup, and image-guided biopsy. CONCLUSION: Tomosynthesis improves interpretive performance and will likely replace conventional 2D mammography in clinical practice.

Knowledge of Density and Screening Ultrasound.

To determine breast density awareness and attitudes regarding supplemental breast ultrasound screening since implementation of the nation's first breast density notification law, Connecticut Public Act 09-41. A self-administered survey was distributed at a Connecticut academic breast imaging center between February 2013 and February 2014. Women with prior mammography reports describing heterogeneous or extremely dense breast tissue were invited to participate when presenting for screening mammography, screening ultrasound, or both. Data were collected on breast density awareness, history of prior ultrasounds, attitudes toward ultrasound and breast-cancer risk, and demographics. Data were collected from 950 completed surveys. The majority of surveyed women (92%) were aware of their breast density, and 77% had undergone a prior screening ultrasound. Forty-three percent of participants who were aware of their breast density also expressed increased anxiety about developing breast cancer due to having dense breast tissue. Caucasian race and higher education were significantly associated (p < 0.05) with knowledge of personal breast density (93% and 95%, respectively) and having a prior screening breast ultrasound (79% and 80%, respectively). Patients with less than a college degree (82%) were significantly more likely to rely exclusively on their provider's recommendation regarding obtaining screening ultrasound (p < 0.05). Breast density awareness is strongly associated with higher education, higher income, and Caucasian race. Non-Caucasian patients and those with less than a college education rely more heavily on their physicians' recommendations regarding screening ultrasound. Among women aware of their increased breast density, nearly half reported associated increased anxiety regarding the possibility of developing breast cancer.

Tomosynthesis in the Diagnostic Setting: Changing Rates of BI-RADS Final Assessment over Time.

Purpose To evaluate the effect of tomosynthesis in diagnostic mammography on the Breast Imaging Reporting and Data System (BI-RADS) final assessment categories over time. Materials and Methods This retrospective study was approved by the institutional review board. The authors reviewed all diagnostic mammograms obtained during a 12-month interval before (two-dimensional [2D] mammography [June 2, 2010, to June 1, 2011]) and for 3 consecutive years after (tomosynthesis year 1 [2012], tomosynthesis year 2 [2013], and tomosynthesis year 3 [2014]) the implementation of tomosynthesis. The requirement to obtain informed consent was waived. The rates of BI-RADS final assessment categories 1-5 were compared between the 2D and tomosynthesis groups. The positive predictive values after biopsy (PPV3) for BI-RADS category 4 and 5 cases were compared. The mammographic features (masses, architectural distortions, calcifications, focal asymmetries) of lesions categorized as probably benign (BI-RADS category 3) and those for which biopsy was recommended (BI-RADS category 4 or 5) were reviewed. The χ(2) test was used to compare the rates of BI-RADS final assessment categories 1-5 between the two groups, and multivariate logistic regression analysis was performed to compare all diagnostic studies categorized as BI-RADS 3-5. Results There was an increase in the percentage of cases reported as negative or benign (BI-RADS category 1 or 2) with tomosynthesis (58.7% with 2D mammography vs 75.8% with tomosynthesis at year 3, P < .0001). A reduction in the percentage of probably benign (BI-RADS category 3) final assessments also occurred (33.3% with 2D mammography vs 16.4% with tomosynthesis at year 3, P < .0001). Although the rates of BI-RADS 4 or 5 assessments did not change significantly with tomosynthesis (8.0% with 2D mammography vs 7.8% with tomosynthesis at year 3, P = .2), there was a significant increase in the PPV3 (29.6% vs 50%, respectively; P < .0001). These trends increased during the 3 years of tomosynthesis use. Conclusion Tomosynthesis in the diagnostic setting resulted in progressive shifts in the BI-RADS final assessment categories over time, with a significant increase in the proportion of studies classified as normal, a continued decrease in the rate of studies categorized as probably benign, and improved diagnostic confidence in biopsy recommendations. (©) RSNA, 2016.

Cost-Effectiveness of Tomosynthesis in Annual Screening Mammography.

OBJECTIVE: The purpose of this study was to evaluate the cost-effectiveness of the addition of annual screening tomosynthesis to 2D digital mammography alone for women beginning at 40 years old and to determine differences for age decade subgroups. MATERIALS AND METHODS: Decision-tree analysis comparing annual tomosynthesis versus 2D mammography alone from a federal payer perspective and lifetime horizon was created from published multiinstitutional data, published institutional data, literature values, and Medicare reimbursement rates. Cost-effectiveness was calculated through incremental cost-effectiveness ratios and net monetary benefit calculations. Sensitivity analyses were performed to determine the implication of different variables including changes in recall rate and disutility for false-positives. RESULTS: Base-case analysis showed an incremental cost per quality-adjusted life year gained for tomosynthesis over 2D alone for all ages (≥ 40 years old) of $20,230, 40- to 49-year-old subgroup of $20,976, 50- to 59-year-old subgroup of $49,725, 60- to 69-year-old subgroup of $44,641, and ≥ 70-year-old subgroup of $82,500. Net monetary benefit per decade in the 40- to 49-year-old subgroup was $1,598, 50- to 59-year-old subgroup of $546, 60- to 69-year-old subgroup of $535, and ≥ 70-year-old subgroup of $501. Tomosynthesis was the better strategy in 63.2% of the iterations according to probabilistic sensitivity analysis. CONCLUSION: Addition of annual screening tomosynthesis to 2D mammography beginning at the age of 40 years was cost-effective compared with 2D mammography alone in our analysis. Three times greater net monetary benefits were found in women 40-49 years old compared with those 50-59 years old.

Tomosynthesis-detected Architectural Distortion: Management Algorithm with Radiologic-Pathologic Correlation.

As use of digital breast tomosynthesis becomes increasingly widespread, new management challenges are inevitable because tomosynthesis may reveal suspicious lesions not visible at conventional two-dimensional (2D) full-field digital mammography. Architectural distortion is a mammographic finding associated with a high positive predictive value for malignancy. It is detected more frequently at tomosynthesis than at 2D digital mammography and may even be occult at conventional 2D imaging. Few studies have focused on tomosynthesis-detected architectural distortions to date, and optimal management of these distortions has yet to be well defined. Since implementing tomosynthesis at our institution in 2011, we have learned some practical ways to assess architectural distortion. Because distortions may be subtle, tomosynthesis localization tools plus improved visualization of adjacent landmarks are crucial elements in guiding mammographic identification of elusive distortions. These same tools can guide more focused ultrasonography (US) of the breast, which facilitates detection and permits US-guided tissue sampling. Some distortions may be sonographically occult, in which case magnetic resonance imaging may be a reasonable option, both to increase diagnostic confidence and to provide a means for image-guided biopsy. As an alternative, tomosynthesis-guided biopsy, conventional stereotactic biopsy (when possible), or tomosynthesis-guided needle localization may be used to achieve tissue diagnosis. Practical uses for tomosynthesis in evaluation of architectural distortion are highlighted, potential complications are identified, and a working algorithm for management of tomosynthesis-detected architectural distortion is proposed.

Early clinical experience with digital breast tomosynthesis for screening mammography.

PURPOSE: To examine recall rates from screening mammography and the mammographic findings that caused recall in women who underwent digital breast tomosynthesis with conventional mammography (referred to as two-dimensional [ 2D two-dimensional ] with three-dimensional [ 3D three-dimensional ] imaging [ 2D two-dimensional + 3D three-dimensional ]) and in women who underwent conventional mammography alone (referred to as 2D two-dimensional ). MATERIALS AND METHODS: This was an institutional review board-approved, HIPAA-compliant study with waivers of informed consent. A retrospective review of 2D two-dimensional + 3D three-dimensional and 2D two-dimensional screening mammograms from August 1, 2011, to December 31, 2012, was performed. Recall rates and abnormalities that caused recall were compared by controlling for differences in patient age, breast density, and risk factors. Cancer detection rate was assessed from this time period and from 1 year before the introduction of tomosynthesis for a historic control. RESULTS: This study included 17 955 screening mammograms; of the total, there were 8591 (47.8%) 2D two-dimensional + 3D three-dimensional screening examinations and 9364 (52.2%) 2D two-dimensional examinations. The recall rate was 7.8% (671 of 8592) for 2D two-dimensional + 3D three-dimensional and 12.3% (1154 of 9364) for 2D two-dimensional (P < .0001); the rate of recall was 36.6% lower in the 2D two-dimensional + 3D three-dimensional group than in the 2D two-dimensional group. Recall rates for the 2D two-dimensional + 3D three-dimensional group were significantly lower for patients with asymmetries, ( 2D two-dimensional + 3D three-dimensional vs 2D two-dimensional , 3.1% [267 of 8591] vs 7.4% [689 of 9364], respectively; P < .0001) and calcifications ( 2D two-dimensional + 3D three-dimensional vs 2D two-dimensional , 2.4% [205 of 8591] vs 3.2% [297 of 9364], respectively; P = .0014). For patients with masses and architectural distortion, the difference in recall rates was not significant (masses: 2D two-dimensional + 3D three-dimensional vs 2D two-dimensional , 2.5% [215 of 8591] vs 2.5% [237 of 9364], respectively; P = .90; architectural distortion: 2D two-dimensional + 3D three-dimensional vs 2D two-dimensional , 0.68% [58 of 8591] vs 0.69% [65 of 9364]; P = .88). Cancer detection was highest in the 2D two-dimensional + 3D three-dimensional group at 5.9 cancers per 1000 examinations, with 5.7 cancers per 1000 examinations in the concurrent 2D two-dimensional group, and 4.4 cancers per 1000 examinations in the historic control. CONCLUSION: Use of tomosynthesis ( 2D two-dimensional + 3D three-dimensional ) compared with conventional mammography ( 2D two-dimensional ) is associated with a lower recall rate of screening mammography, most often for asymmetries.

Diagnostic accuracy and recall rates for digital mammography and digital mammography combined with one-view and two-view tomosynthesis: results of an enriched reader study.

OBJECTIVE: The purpose of this study was to compare two methods of combining tomosynthesis with digital mammography by assessing diagnostic accuracy and recall rates for digital mammography alone and digital mammography combined with one-view tomosynthesis and two-view tomosynthesis. SUBJECTS AND METHODS: Three hundred ten cases including biopsy-proven malignancies (51), biopsy-proven benign findings (47), recalled screening cases (138), and negative screening cases (74) were reviewed by 15 radiologists sequentially using digital mammography, adding one-view tomosynthesis, and then two-view tomosynthesis. Cases were assessed for recall and assigned a BI-RADS score and probability of malignancy for each imaging method. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analysis. Screening recall rates were compared using pooled logistical regression analysis. A p value of < 0.0167 was considered significant. RESULTS: The area under the ROC curve (AUC) for digital mammography (DM), DM plus one-view tomosynthesis, and DM plus two-view tomosynthesis was 0.828, 0.864, and 0.895, respectively. Both one-view and two-view tomosynthesis plus DM were significantly better than DM alone (Δ AUCs 0.036 [p = 0.009] and 0.068 [p < 0.001]). Average noncancer recall rates for digital mammography, DM plus one-view tomosynthesis, and DM plus two-view tomosynthesis were 44.2%, 27.2%, and 24.0%, respectively. Combined with DM, one-view and two-view tomosynthesis both showed significantly lower noncancer recall rates than digital mammography alone (p < 0.001). Digital mammography with two-view tomosynthesis showed a significantly lower recall rate than digital mammography with one-view tomosynthesis (p < 0.001). Diagnostic accuracy for dense (Δ AUC, 0.091%; p < 0.001) and nondense (Δ AUC, 0.035%; p = 0.001) breasts improved with DM plus two-view tomosynthesis compared with digital mammography alone. Compared with digital mammography, diagnostic sensitivity for invasive cancers increased with the addition of both one-view (Δ12.0%, p < 0.001) and two-view (Δ21.7%, p < 0.001) tomosynthesis. CONCLUSION: The addition of one-view tomosynthesis to conventional digital mammography improved diagnostic accuracy and reduced the recall rate; however, the addition of two-view tomosynthesis provided twice the performance gain in diagnostic accuracy while further reducing the recall rate.

Breast ultrasonography: state of the art.

Ultrasonography (US) is an indispensable tool in breast imaging and is complementary to both mammography and magnetic resonance (MR) imaging of the breast. Advances in US technology allow confident characterization of not only benign cysts but also benign and malignant solid masses. Knowledge and understanding of current and emerging US technology, along with the application of meticulous scanning technique, is imperative for image optimization and diagnosis. The ability to synthesize breast US findings with multiple imaging modalities and clinical information is also necessary to ensure the best patient care. US is routinely used to guide breast biopsies and is also emerging as a supplemental screening tool in women with dense breasts and a negative mammogram. This review provides a summary of current state-of-the-art US technology, including elastography, and applications of US in clinical practice as an adjuvant technique to mammography, MR imaging, and the clinical breast examination. The use of breast US for screening, preoperative staging for breast cancer, and breast intervention will also be discussed.

Comparison of tomosynthesis plus digital mammography and digital mammography alone for breast cancer screening.

PURPOSE: To compare screening recall rates and cancer detection rates of tomosynthesis plus conventional digital mammography to those of conventional digital mammography alone. MATERIALS AND METHODS: All patients presenting for screening mammography between October 1, 2011, and September 30, 2012, at four clinical sites were reviewed in this HIPAA-compliant retrospective study, for which the institutional review board granted approval and waived the requirement for informed consent. Patients at sites with digital tomosynthesis were offered screening with digital mammography plus tomosynthesis. Patients at sites without tomosynthesis underwent conventional digital mammography. Recall rates were calculated and stratified according to breast density and patient age. Cancer detection rates were calculated and stratified according to the presence of a risk factor for breast cancer. The Fisher exact test was used to compare the two groups. Multivariate logistic regression was used to assess the effect of screening method, breast density, patient age, and cancer risk on the odds of recall from screening. RESULTS: A total of 13 158 patients presented for screening mammography; 6100 received tomosynthesis. The overall recall rate was 8.4% for patients in the tomosynthesis group and 12.0% for those in the conventional mammography group (P < .01). The addition of tomosynthesis reduced recall rates for all breast density and patient age groups, with significant differences (P < .05) found for scattered fibroglandular, heterogeneously dense, and extremely dense breasts and for patients younger than 40 years, those aged 40-49 years, those aged 50-59 years, and those aged 60-69 years. These findings persisted when multivariate logistic regression was used to control for differences in age, breast density, and elevated risk of breast cancer. The cancer detection rate was 5.7 per 1000 in patients receiving tomosynthesis versus 5.2 per 1000 in patients receiving conventional mammography alone (P = .70). CONCLUSION: Patients undergoing tomosynthesis plus digital mammography had significantly lower screening recall rates. The greatest reductions were for those younger than 50 years and those with dense breasts. A nonsignificant 9.5% increase in cancer detection was observed in the tomosynthesis group.

Assessing radiologist performance using combined digital mammography and breast tomosynthesis compared with digital mammography alone: results of a multicenter, multireader trial.

PURPOSE: To compare radiologists' diagnostic accuracy and recall rates for breast tomosynthesis combined with digital mammography versus digital mammography alone. MATERIALS AND METHODS: Institutional review board approval was obtained at each accruing institution. Participating women gave written informed consent. Mediolateral oblique and craniocaudal digital mammographic and tomosynthesis images of both breasts were obtained from 1192 subjects. Two enriched reader studies were performed to compare digital mammography with tomosynthesis against digital mammography alone. Study 1 comprised 312 cases (48 cancer cases) with images read by 12 radiologists; study 2, 312 cases (51 cancer cases) with 15 radiologists. Study 1 readers recorded only that an abnormality requiring recall was present; study 2 readers had additional training and recorded both lesion type and location. Diagnostic accuracy was compared with receiver operating characteristic analysis. Recall rates of noncancer cases, sensitivity, specificity, and positive and negative predictive values determined by analyzing Breast Imaging Reporting and Data System scores were compared for the two methods. RESULTS: Diagnostic accuracy for combined tomosynthesis and digital mammography was superior to that of digital mammography alone. Average difference in area under the curve in study 1 was 7.2% (95% confidence interval [CI]: 3.7%, 10.8%; P < .001) and in study 2 was 6.8% (95% CI: 4.1%, 9.5%; P < .001). All 27 radiologists increased diagnostic accuracy with addition of tomosynthesis. Recall rates for noncancer cases for all readers significantly decreased with addition of tomosynthesis (range, 6%-67%; P < .001 for 25 readers, P < .03 for all readers). Increased sensitivity was largest for invasive cancers: 15% and 22% in studies 1 and 2 versus 3% for in situ cancers in both studies. CONCLUSION: Addition of tomosynthesis to digital mammography offers the dual benefit of significantly increased diagnostic accuracy and significantly reduced recall rates for noncancer cases. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120674/-/DC1.

Screening US in patients with mammographically dense breasts: initial experience with Connecticut Public Act 09-41.

PURPOSE: To determine performance and utilization of screening breast ultrasonography (US) in women with dense breast tissue who underwent additional screening breast US in the 1st year since implementation of Connecticut Public Act 09-41 requiring radiologists to inform patients with heterogeneous or extremely dense breasts at mammography that they may benefit from such examination. MATERIALS AND METHODS: Informed consent was waived for this institutional review board-approved, HIPAA-compliant retrospective review of 935 women with dense breasts at mammography who subsequently underwent handheld screening and whole-breast US from October 1, 2009, through September 30, 2010. RESULTS: Of 935 women, 614 (65.7%) were at low risk, 149 (15.9%) were at intermediate risk, and 87 (9.3%) were at high risk for breast cancer. Of the screening breast US examinations, in 701 (75.0%), results were classified as Breast Imaging Reporting and Data System (BI-RADS) category 1 or 2; in 187 (20.0%), results were classified as BI-RADS category 3; and in 47 (5.0%), results were classified as BI-RADS category 4. Of 63 aspirations or biopsies recommended and performed in 53 patients, in nine, lesions were BI-RADS category 3, and in 54, lesions were BI-RADS category 4. Among 63 biopsies and aspirations, three lesions were malignant (all BI-RADS category 4, diagnosed with biopsy). All three cancers were smaller than 1 cm, were found in postmenopausal patients, and were solid masses. One cancer was found in each risk group. In 44 of 935 (4.7%) patients, examination results were false-positive. Overall positive predictive value (PPV) for biopsy or aspirations performed in patients with BI-RADS category 4 masses was 6.5% (three of 46; 95% confidence interval [CI]: 1.7%, 19%). Overall cancer detection rate was 3.2 cancers per 1000 women screened (three of 935; 95% CI: 0.8 cancers per 1000 women screened, 10 cancers per 1000 women screened). CONCLUSION: Technologist-performed handheld screening breast US offered to women in the general population with dense breasts can aid detection of small mammographically occult breast cancers (cancer detection rate, 0.8-10 cancers per 1000 women screened), although the overall PPV is low.