Screening Algorithms in Dense Breasts: AJR Expert Panel Narrative Review.

Screening mammography reduces breast cancer mortality; however, when used to examine women with dense breasts, its performance and resulting benefits are reduced. Increased breast density is an independent risk factor for breast cancer. Digital breast tomosynthesis (DBT), ultrasound (US), molecular breast imaging (MBI), MRI, and contrast-enhanced mammography (CEM) each have shown improved cancer detection in dense breasts when compared with 2D digital mammography (DM). DBT is the preferred mammographic technique for producing a simultaneous reduction in recalls (i.e., additional imaging). US further increases cancer detection after DM or DBT and reduces interval cancers (cancers detected in the interval between recommended screening examinations), but it also produces substantial additional false-positive findings. MBI improves cancer detection with an effective radiation dose that is approximately fourfold that of DM or DBT but is still within accepted limits. MRI provides the greatest increase in cancer detection and reduces interval cancers and late-stage disease; abbreviated techniques will reduce cost and improve availability. CEM appears to offer performance similar to that of MRI, but further validation is needed. Dense breast notification will soon be a national standard; therefore, understanding the performance of mammography and supplemental modalities is necessary to optimize screening for women with dense breasts.

Effect of age on breast cancer screening using tomosynthesis in combination with digital mammography.

PURPOSE: To determine the effect of tomosynthesis imaging as a function of age for breast cancer screening. METHODS: Screening performance metrics from 13 institutions were examined for 12 months prior to introduction of tomosynthesis (period 1) and compared to those after introduction of tomosynthesis (period 2, range 3-22 months). Screening metrics for women ages 40-49, 50-59, 60-69, and 70+ , included rates per 1000 screens for recalls, biopsies, cancers, and invasive cancers detected. RESULTS: Performance parameters were compared for women screened with digital mammography alone (n = 278,908) and digital mammography + tomosynthesis (n = 173,414). Addition of tomosynthesis to digital mammography produced significant reductions in recall rates for all age groups and significant increases in cancer detection rates for women 40-69. Largest recall rate reduction with tomosynthesis was for women 40-49, decreasing from 137 (95% CI 117-156) to 115 (95% CI 95-135); difference, -22 (95% CI -26 to -18; P < .001). Simultaneous increase in invasive cancer detection rate for women 40-49 from 1.6 (95% CI 1.2-1.9) to 2.7 (95% CI 2.2-3.1) with tomosynthesis (difference, 1.1; 95% CI 0.6-1.6; P < .001) was observed. CONCLUSIONS: Addition of tomosynthesis to digital mammography increased invasive cancer detection rates for women 40-69 and decreased recall rates for all age groups with largest performance gains seen in women 40-49. The similar performance seen with tomosynthesis screening for women in their 40s compared to digital mammography for women in their 50s argues strongly for commencement of mammography screening at age 40 using tomosynthesis.

Comparison of intra-operative specimen mammography to standard specimen mammography for excision of non-palpable breast lesions: a randomized trial.

Standard specimen mammography (SSM) is performed in the radiology department after wire-localized excision of non-palpable breast lesions to confirm the presence of the target and evaluate margins. Alternatively, intra-operative specimen mammography (ISM) allows surgeons to view images in the operating room (OR). We conducted a randomized study comparing ISM and SSM. Women undergoing wire-localized excision for breast malignancy or imaging abnormality were randomized to SSM or ISM. For SSM, the specimen was transported to the radiology department for imaging and interpretation. For ISM, the specimen was imaged in the OR for interpretation by the surgeon and sent for SSM. Interpretation time was from specimen leaving OR until radiologist interpretation for SSM and from placement in ISM device until surgeon interpretation for ISM. Procedure and interpretation times were compared. Concordance between ISM and SSM for target and margins was evaluated. 72 patients were randomized, 36 ISM and 36 SSM. Median procedure times were similar, 48.5 (17-138) min for ISM, and 54 (17-40) min for SSM (p = 0.72), likely since specimens in both groups traveled to radiology for SSM. Median interpretation time was significantly shorter with ISM, 1 (0.5-2.0) and 9 (4-16) min for ISM and SSM, respectively (p < 0.0001). Among specimens with ISM and SSM, concordance was 100 % (35/35) for target and 93 % (14/15) for margins. In this randomized trial, use of ISM compared with SSM significantly reduced interpretation times, while accurately identifying the target. This could result in decreased operative costs from shorter OR times with use of ISM.

Intraoperative micro-computed tomography (micro-CT): a novel method for determination of primary tumour dimensions in breast cancer specimens.

OBJECTIVES: Micro-CT is a promising modality to determine breast tumour size in three dimensions in intact lumpectomy specimens. We compared the accuracy of tumour size measurements using specimen micro-CT with measurements using multimodality pre-operative imaging. METHODS: A tabletop micro-CT was used to image breast lumpectomy specimens. The largest tumour dimension on three-dimensional reconstructed micro-CT images of the specimen was compared with the measurements determined by pre-operative mammography, ultrasound and MRI. The largest dimension of pathologic invasive cancer size was used as the gold standard reference to assess the accuracy of imaging assessments. RESULTS: 50 invasive breast cancer specimens in 50 patients had micro-CT imaging. 42 were invasive ductal carcinoma, 6 were invasive lobular carcinoma and 2 were other invasive cancer. Median patient age was 63 years (range 33-82 years). When compared with the largest pathologic tumour dimension, micro-CT measurements had the best correlation coefficient (r = 0.82, p < 0.001) followed by MRI (r = 0.78, p < 0.001), ultrasound (r = 0.61, p < 0.001) and mammography (r = 0.40, p < 0.01). When compared with pre-operative modalities, micro-CT had the best correlation coefficient (r = 0.86, p < 0.001) with MRI, followed by ultrasound (r = 0.60, p < 0.001) and mammography (r = 0.54, p < 0.001). Overall, mammography and ultrasound tended to underestimate the largest tumour dimension, while MRI and micro-CT overestimated the largest tumour dimension more frequently. CONCLUSION: Micro-CT is a potentially useful tool for accurate assessment of tumour dimensions within a lumpectomy specimen. Future studies need to be carried out to see if this technology could have a role in margin assessment. ADVANCES IN KNOWLEDGE: Micro-CT is a promising new technique which could potentially be used for rapid assessment of breast cancer dimensions in an intact lumpectomy specimen in order to guide surgical excision.

How to approach breast lesions in children and adolescents.

UNLABELLED: Assessment of a pediatric breast lesion always starts with clinical evaluation. When imaging of a pediatric breast is indicated, ultrasound is the mainstay. The vast majority of pediatric breast complaints are of benign etiology, therefore the diagnostic/management approach emphasizes "first do no harm". Correlation with age and clinical history helps to direct diagnosis. It is essential to be familiar with the imaging appearance of the normal developing breast at various Tanner stages, in order to diagnose physiologic breast findings and to minimize unnecessary biopsies in young breasts vulnerable to injury. Normal anatomic structures, developmental conditions, benign neoplastic and non-neoplastic lesions are common causes of breast complaints in children. Uncommon benign masses and rarely, secondary more than primary malignancies may present in a pediatric breast. Chest wall masses such as Ewing's sarcoma or rhabdomyosarcoma occur in children and may involve the breast via contiguous growth or locoregional metastasis. In addition, special attention should be given to any breast lesion in a child with risk factors predisposing to breast cancer, such as known extramammary malignancy, genetic mutations, prior mantle irradiation, or strong family history of breast cancer, which usually requires biopsy to exclude the possibility of malignancy. CONCLUSION: The developing breast is vulnerable to injury, and because breast malignancy is uncommon in children, diagnostic and management approach emphasizes "first do no harm". Understanding normal breast development and the spectrum of common and uncommon pediatric breast lesions are key to the correct diagnosis.

Preoperative Tomosynthesis-guided Needle Localization of Mammographically and Sonographically Occult Breast Lesions.

PURPOSE: To assess the feasibility and accuracy of digital breast tomosynthesis (DBT)-guided needle localization for DBT-detected suspicious abnormalities not visualized with other modalities and to analyze the imaging and pathologic characteristics of abnormalities detected only with DBT to determine the positive predictive value for malignancy. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board, and the requirement to obtain informed consent was waived. A retrospective query of the imaging database identified 34 consecutive women (average age, 55 years; age range, 28-84 years) with 36 lesions who underwent DBT-guided needle localization between April 2011 and January 2013 with use of commercially available equipment. Imaging findings and medical records were reviewed. Findings that were attributable to previous surgical changes were classified as benign or probably benign and excluded from analysis because the lesions did not proceed to localization. RESULTS: Architectural distortion was the imaging finding identified in all 36 abnormalities (100%). Findings from pathologic examination after the first attempt at localization were concordant with those from imaging in 35 of the 36 lesions (97%), which is suggestive of appropriate sampling. Histologic findings were malignant in 17 of the 36 lesions (47%; 95% confidence interval: 30.4%, 64.5%). Thirteen of the 17 lesions (76%; 95% confidence interval: 50.1%, 93.1%) were invasive malignancies. Twenty-two of the 36 abnormalities (61%) were either malignant or high-risk lesions (atypical ductal hyperplasia, lobular carcinoma in situ, atypical lobular hyperplasia). CONCLUSION: DBT-guided needle localization is an accurate and feasible method with which to biopsy DBT-detected suspicious architectural distortions not visualized at mammography or sonography. The high risk of malignancy in abnormalities detected only with DBT (47%) confirms that routine biopsy is required for histologic analysis.

To do or not to do: axillary nodal evaluation after ACOSOG Z0011 Trial.

Methods of axillary evaluation in invasive breast cancer continue to evolve. The recent American College of Surgeons Oncology Group Z0011 Trial is a prospective, randomized, multicenter trial that compared the survival and locoregional recurrence rates after complete axillary lymph node dissection (ALND) versus sentinel node biopsy (SNB) alone in women with a positive sentinel node in an effort to avoid the complications associated with ALND. As the results of this trial are implemented clinically, affecting surgical management of axillary metastatic disease, radiologists may need to redefine their role in the preoperative assessment of the axilla. Before the Z0011 trial, breast imagers worked to identify axillary metastases preoperatively, allowing appropriate patients to proceed directly to ALND and avoiding the need for SNB. However, the Z0011 trial concluded that ALND may not be necessary in women with metastatic axillary disease who meet the trial criteria. In the Z0011 trial, after 6 years of median follow-up there was no difference in either locoregional recurrence or survival among the women who underwent SNB alone compared with those who underwent ALND, suggesting that ALND is unnecessary in a subset of women with a positive node at SNB. These results raise questions about how aggressively radiologists should pursue percutaneous sampling of axillary nodes, as some practitioners conclude that, in an otherwise eligible woman, positive results from imaging-guided percutaneous biopsy preclude a Z0011 trial-directed pathway. Debate about the best way to implement the results of the Z0011 trial into daily clinical practice exists. It is important for breast imagers to work closely with breast surgeons to provide the most appropriate treatment course for each patient.

Clinical evaluation of a mobile digital specimen radiography system for intraoperative specimen verification.

OBJECTIVE: Use of mobile digital specimen radiography systems expedites intraoperative verification of excised breast specimens. The purpose of this study was to evaluate the performance of a such a system for verifying targets. MATERIALS AND METHODS: A retrospective review included 100 consecutive pairs of breast specimen radiographs. Specimens were imaged in the operating room with a mobile digital specimen radiography system and then with a conventional digital mammography system in the radiology department. Two expert reviewers independently scored each image for image quality on a 3-point scale and confidence in target visualization on a 5-point scale. A target was considered confidently verified only if both reviewers declared the target to be confidently detected. RESULTS: The 100 specimens contained a total of 174 targets, including 85 clips (49%), 53 calcifications (30%), 35 masses (20%), and one architectural distortion (1%). Although a significantly higher percentage of mobile digital specimen radiographs were considered poor quality by at least one reviewer (25%) compared with conventional digital mammograms (1%), 169 targets (97%), were confidently verified with mobile specimen radiography; 172 targets (98%) were verified with conventional digital mammography. Three faint masses were not confidently verified with mobile specimen radiography, and conventional digital mammography was needed for confirmation. One faint mass and one architectural distortion were not confidently verified with either method. CONCLUSION: Mobile digital specimen radiography allows high diagnostic confidence for verification of target excision in breast specimens across target types, despite lower image quality. Substituting this modality for conventional digital mammography can eliminate delays associated with specimen transport, potentially decreasing surgical duration and increasing operating room throughput.

Breast cancer screening using tomosynthesis in combination with digital mammography.

IMPORTANCE: Mammography plays a key role in early breast cancer detection. Single-institution studies have shown that adding tomosynthesis to mammography increases cancer detection and reduces false-positive results. OBJECTIVE: To determine if mammography combined with tomosynthesis is associated with better performance of breast screening programs in the United States. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of screening performance metrics from 13 academic and nonacademic breast centers using mixed models adjusting for site as a random effect. EXPOSURES: Period 1: digital mammography screening examinations 1 year before tomosynthesis implementation (start dates ranged from March 2010 to October 2011 through the date of tomosynthesis implementation); period 2: digital mammography plus tomosynthesis examinations from initiation of tomosynthesis screening (March 2011 to October 2012) through December 31, 2012. MAIN OUTCOMES AND MEASURES: Recall rate for additional imaging, cancer detection rate, and positive predictive values for recall and for biopsy. RESULTS: A total of 454,850 examinations (n=281,187 digital mammography; n=173,663 digital mammography + tomosynthesis) were evaluated. With digital mammography, 29,726 patients were recalled and 5056 biopsies resulted in cancer diagnosis in 1207 patients (n=815 invasive; n=392 in situ). With digital mammography + tomosynthesis, 15,541 patients were recalled and 3285 biopsies resulted in cancer diagnosis in 950 patients (n=707 invasive; n=243 in situ). Model-adjusted rates per 1000 screens were as follows: for recall rate, 107 (95% CI, 89-124) with digital mammography vs 91 (95% CI, 73-108) with digital mammography + tomosynthesis; difference, -16 (95% CI, -18 to -14; P < .001); for biopsies, 18.1 (95% CI, 15.4-20.8) with digital mammography vs 19.3 (95% CI, 16.6-22.1) with digital mammography + tomosynthesis; difference, 1.3 (95% CI, 0.4-2.1; P = .004); for cancer detection, 4.2 (95% CI, 3.8-4.7) with digital mammography vs 5.4 (95% CI, 4.9-6.0) with digital mammography + tomosynthesis; difference, 1.2 (95% CI, 0.8-1.6; P < .001); and for invasive cancer detection, 2.9 (95% CI, 2.5-3.2) with digital mammography vs 4.1 (95% CI, 3.7-4.5) with digital mammography + tomosynthesis; difference, 1.2 (95% CI, 0.8-1.6; P < .001). The in situ cancer detection rate was 1.4 (95% CI, 1.2-1.6) per 1000 screens with both methods. Adding tomosynthesis was associated with an increase in the positive predictive value for recall from 4.3% to 6.4% (difference, 2.1%; 95% CI, 1.7%-2.5%; P < .001) and for biopsy from 24.2% to 29.2% (difference, 5.0%; 95% CI, 3.0%-7.0%; P < .001). CONCLUSIONS AND RELEVANCE: Addition of tomosynthesis to digital mammography was associated with a decrease in recall rate and an increase in cancer detection rate. Further studies are needed to assess the relationship to clinical outcomes.

Auditing a breast MRI practice: performance measures for screening and diagnostic breast MRI.

PURPOSE: Breast MRI is increasingly used for both screening and diagnostic purposes. Although performance benchmarks for screening and diagnostic mammography have been published, performance benchmarks for breast MRI have yet to be established. The purpose of this study was to comprehensively evaluate breast MRI performance measures, stratified by screening and diagnostic indications, from a single academic institution. METHODS: Institutional review board approval was acquired for this HIPAA-compliant study. Informed consent was not required. Retrospective review of the institutional database identified all breast MRI examinations performed from April 1, 2007, to March 31, 2008. After application of exclusion criteria, the following performance measures for screening and diagnostic indications were calculated: cancer detection rate, positive predictive value (PPV), and abnormal interpretation rates. RESULTS: The study included 2,444 examinations, 1,313 for screening and 1,131 for diagnostic indications. The cancer detection rates were 14 per 1,000 screening breast MRI examinations and 47 per 1,000 diagnostic examinations (P < .00001). The abnormal interpretation rate was 12% (152 of 1,313) for screening and 17% (194 of 1,131) for diagnostic indications (P = .00008). The PPVs of MRI were lower for screening [PPV1 (abnormal findings) = 12%, PPV2 (biopsy recommended) = 24%, PPV3 (biopsy performed) = 27%] compared with diagnostic indications (PPV1 (abnormal findings) = 28%, PPV2 (biopsy recommended) = 36%, PPV3 (biopsy performed) = 38%]. CONCLUSIONS: Breast MRI performance measures differ significantly between screening and diagnostic MRI indications. Medical audits for breast MRI should calculate performance measures for screening and diagnostic breast MRI separately, as recommended for mammography.

Surgical excision of radial scars diagnosed by core biopsy may help predict future risk of breast cancer.

Radial scars (RS's) are benign breast lesions known to be associated with carcinomas and other high-risk lesions (HRL's). The upgrade rate to carcinoma after core biopsy revealing RS is 0-40 %. We sought to determine the outcomes of RS with and without HRL diagnosed by core biopsy. Patients who underwent core biopsy revealing RS without carcinoma at our institution between 1/1996 and 11/2012 were identified from a surgical pathology database. Retrospective chart review was utilized to classify patients as RS-no HRL or RS-HRL. HRL was defined as ADH, LCIS, and/or ALH. We determined upgrade rate to carcinoma at surgical excision, and upgrade to HRL for RS-no HRL patients. Univariate analysis was performed to identify risk factors for upgrade in RS-no HRL patients. 156 patients underwent core biopsy revealing RS, 131 RS-no HRL (84 %), and 25 RS-HRL (16 %). The overall rate of upgrade to invasive carcinoma was 0.8 % (1/124). 1.0 % (1/102) of RS-no HRL and 13.6 % (3/22) of RS-HRL patients were upgraded to DCIS (P = 0.0023). The upgrade of RS-no HRL to HRL at excision was 21.6 % (22/102). By univariate analysis, RS-no HRL with radiologic appearance of a mass/architectural distortion had a significantly higher rate of upgrade to HRL or carcinoma compared with calcifications (P = 0.03). Excision of RS to rule out associated invasive carcinoma is not warranted, given a <1 % rate of upgrade at excision. However, excision to evaluate for non-invasive cancer or HRL may be considered to help guide clinical decision-making about use of chemoprevention.

Digital breast tomosynthesis in the analysis of fat-containing lesions.

Digital breast tomosynthesis (DBT) is rapidly emerging as an important clinical tool for both screening and diagnosis. DBT improves upon mammography by depicting breast tissue on a dynamic sequence of cross-sectional images reconstructed in planes corresponding to their mammographic planes of acquisition. DBT results in markedly reduced summation of overlapping tissue and depicts the margins of masses in far greater detail than mammography. Fat is commonly recognized in both benign and malignant breast masses at DBT, even when no fat is appreciated at mammography. In cases of encapsulated fat-containing masses, the increased detail at DBT often allows the radiologist to definitively classify a mass as benign (eg, lipoma, hamartoma, galactocele, lipid cyst) when mammographic findings alone are equivocal, thereby avoiding unnecessary biopsy or workup. However, when learning to read DBT images, many radiologists misinterpret this rule, mistaking the presence of any fat within a mass for an indication of benignity or an artifact and falsely concluding that an otherwise suspicious mass is not worrisome. If fat seen in breast masses at DBT is not appropriately analyzed, malignant breast masses may be incorrectly classified as probably or even definitely benign. With use of radiologic-pathologic correlation, the authors illustrate cases in which the presence of fat can help correctly classify a mass as benign, and pitfalls in which the presence or absence of fat within a mass is irrelevant and should not influence analysis.

Percutaneous breast biopsy: effect on short-term quality of life.

PURPOSE: To examine the effects of percutaneous breast biopsy on short-term quality of life. MATERIALS AND METHODS: The institutional review board approved this HIPAA-compliant prospective study. From December 1, 2007, through February 28, 2010, women undergoing percutaneous breast biopsy in an academic medical center were recruited to participate in a mixed-mode survey 2-4 days after biopsy. Patients described their biopsy experience by using the Testing Morbidities Index (TMI), a validated instrument for assessing short-term quality of life related to diagnostic testing. The scale ranged from 0 (worst possible experience) to 100 (no adverse effects). Seven attributes were assessed: pain or discomfort before and during testing, fear or anxiety before and during testing, embarrassment during testing, and physical and mental function after testing. Demographic and clinical information were also collected. Univariate and multivariate linear regression analyses were performed to identify significant predictors of TMI score. RESULTS: In 188 women (mean age, 51.4 years; range, 22-80 years), the mean TMI score (±standard deviation) was 82 ± 12. Univariate analysis revealed age and race as significant predictors of the TMI score (P < .05). In the multivariate model, only patient age remained a significant independent predictor (P = .001). TMI scores decreased by approximately three points for every decade decrease in patient age, which suggests that younger women were more adversely affected by the biopsy experience. CONCLUSION: Younger patient age is a significant predictor of decreased short-term quality of life related to percutaneous breast biopsy procedures. Tailored prebiopsy counseling may better prepare women for percutaneous biopsy procedures and improve their experience.

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.

Addition of tomosynthesis to conventional digital mammography: effect on image interpretation time of screening examinations.

PURPOSE: To determine the effect of implementing a screening tomosynthesis program on real-world clinical performance by quantifying differences between interpretation times for conventional screening mammography and combined tomosynthesis and mammography for multiple participating radiologists with a wide range of experience in a large academic center. MATERIALS AND METHODS: In this HIPAA-compliant, institutional review board-approved study, 10 radiologists prospectively read images from screening digital mammography or screening combined tomosynthesis and mammography examinations for 1-hour-long uninterrupted sessions. Images from 3665 examinations (1502 combined and 2163 digital mammography) from July 2012 to January 2013 were interpreted in at least five sessions per radiologist per modality. The number of cases reported during each session was recorded for each reader. The experience level for each radiologist was also correlated to the average number of cases reported per hour. Analysis of variance was used to assess the number of studies interpreted per hour. A linear regression model was used to evaluate correlation between breast imaging experience and time taken to interpret images from both modalities. RESULTS: The mean number of studies interpreted in hour was 23.8 ± 0.55 (standard deviation) (range, 14.4-40.4) for combined tomosynthesis and mammography and 34.0 ± 0.55 (range, 20.4-54.3) for digital mammography alone. A mean of 10.2 fewer studies were interpreted per hour during combined tomosynthesis and mammography compared with digital mammography sessions (P < .0001). The mean interpretation time was 2.8 minutes ± 0.9 (range, 1.5-4.2 minutes) for combined tomosynthesis and mammography and 1.9 minutes ± 0.6 (range, 1.1-3.0) for digital mammography; interpretation time with combined tomosynthesis and mammography was 0.9 minute longer (47% longer) compared with digital mammography alone (P < .0001). With the increase in years of breast imaging experience, the overall additional time required to read images from combined tomosynthesis and mammography examinations decreased (R(2) = 0.52, P = .03). CONCLUSION: Addition of tomosynthesis to mammography results in increased time to interpret images from screening examinations compared with time to interpret images from conventional digital mammography alone.