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Ultrasound
Wendie A. Berg, MD, PhD, FACR, FSBI
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KEY FACTS

  • Imaging

    • Clinical Issues

      TERMINOLOGY

      • Synonyms

        • Sonography
      • Definitions

        • Targeted US: Directed to area of clinical, mammographic, MR, or other imaging abnormality
        • MR-directed US: Directed to abnormality on MR
        • Automated breast US: Typically 3D acquisition obtained in axial plane and reconstructed in coronal plane
        • Spatial compounding: Averaging of signal from multiple (usually off-angle) beams to reduce noise
          • Loss of posterior features
        • Harmonic imaging: Insonates tissue at 1 frequency; receives at multiples of that frequency (usually 2x, e.g., 12 → 24 MHz)
          • Preserves posterior features; reduces noise
        • Elastography: Method to measure stiffness of lesion and surrounding tissue
          • Downgrade soft BI-RADS 4A masses to surveillance and upgrade hard BI-RADS 3 masses to biopsy to ↑ specificity of breast US
      • General Performance Statistics

        • Not limited by breast density
        • ↓ performance in very large breasts (> 4-cm thick) and deep lesions
        • Invasive ductal carcinoma (IDC)
          • 96% sensitivity across series (range: 95-97%) vs. 84% for mammography (range: 81-89%)
        • Invasive lobular carcinoma (ILC)
          • 88% sensitivity across series (range: 68-98%) vs. 71% for mammography (range: 34-92%)
        • DCIS: Wide range of sensitivities, depending on gold standard: ~ 50% in most scenarios
      • Indications

        • Palpable abnormality
          • In combination with mammography: 97.3% sensitivity; 99.4% negative predictive value (NPV) across 9 series
          • Opportunity for direct real-time correlation of imaging and clinical findings
          • Normal fatty lobulation is common source of palpable concern
          • Layer of subcutaneous fat focally thins → underlying dense tissue palpable
          • Use US as initial test for women < 30 years or for those who are pregnant or lactating
            • Mammogram often done initially for women ≥ 30 years, certainly if ≥ 40 years, if not pregnant or lactating
              • Sensitivity of mammography at site of symptoms 78% vs. 98% for US
              • Supplemental cancer detection rate (CDR) of mammography after US in women with symptoms 2/1,000 age 30-39
            • US has greater sensitivity than mammography until ~ age 45
        • Mammographic abnormality
          • Mass, asymmetry, architectural distortion; further evaluation, guided biopsy if needed
        • Guide biopsy
          • ↑ accuracy in sampling palpable masses
            • < 2% miss for US-guided core needle biopsy (CNB) vs. 13% without US guidance; 91% definitive
          • Inflammatory breast cancer: Identify mass, biopsy
          • Nonpalpable masses, US-guided 14-gauge CNB is sufficient in vast majority
            • Definitive result in 93% across series; 2% false-negative rate
            • Poor performance for fine-needle aspiration biopsy (FNAB): 77% overall accuracy, 10% insufficient
          • Suspicious Ca⁺⁺ visible on US
            • US-visible Ca⁺⁺: More likely malignant, more likely invasive carcinoma; specimen x-ray needed on biopsy
            • Benefit to obtaining more material: Possible indication for vacuum-assisted US biopsy
          • Targeted US after MR: Highly variable performance
            • Average 58% success (range: 23-71%)
              • Average 81% (range: 58-100%) of invasive cancers seen
              • Average 50% (range: 20-100%) of DCIS identified
              • Average 52% (range: 16-71%) of benign lesions found
              • 66% of all masses and 33% of nonmass enhancement (NME) seen: 50% of masses ≤ 5 mm, 56% if 6-10 mm, 73% if 11-15 mm, 86% if > 15 mm
            • Average 12% (range: 6-28%) malignancy rate among lesions not seen on targeted US: Need for MR-guided biopsy
        • Pathologic nipple discharge
          • 93% sensitivity to cause of discharge vs. 68% for galactography (2 series)
          • Central papilloma is most common cause; 56-80% sensitivity for US vs. 15-32% for mammography
        • Guide aspiration
          • Aspirate cysts only if painful to patient and requested (BI-RADS 2) or if diagnostic uncertainty (BI-RADS 4)
            • Round, tense cysts most likely to be symptomatic
          • Aspirate/drain breast abscess: Drain can be placed
        • Guide localization for surgery
          • Provide depth ± wire or seed localization; mark overlying skin (optional)
      • US Appropriate

        • Supplemental screening in dense breasts: Handheld or automated
          • After mammography, average CDR 2.8 per 1,000
          • CDR 1-2/1,000 after tomosynthesis (studies ongoing)
          • CDR 4.8-13 cancers per 1,000 high-risk women screened
          • Same incremental CDR for prevalence and incidence screens
          • 88% of cancers seen only on screening US are invasive; median size 10 mm; 85% are node (-); ↑ detection of ILC
          • Average 3.3% risk of US-induced biopsy
          • Average 10% of biopsies prompted only by US prove malignant (range: 5-31%)
          • Performed by physician or technologist
        • Extent of disease in breast
          • Of breasts suspected to have unifocal cancer on mammography and clinically, ~ 48% have additional tumor foci at histopathology
          • Combined mammogram + US depicts ~ 90% of all tumor foci
          • May underestimate tumor size, especially if > 2-3 cm
        • Axillary nodal staging
          • Node can be identified and sampled using FNAB or CNB: Sensitivity 71% for metastasis, specificity 100%
          • Axillary nodal US and biopsy is indicated when mastectomy or neoadjuvant chemotherapy is planned or if palpable suspicious node(s) are present
          • For lumpectomy, no palpable nodes, surgeons may plan only sentinel lymph node excision
            • Preoperative node biopsy is not indicated
        • Intraoperative US: May help achieve clear margins
        • Distinguishing recurrence from scar
          • Lumpectomy scar should ↓ over time, extend to skin incision
          • Recurrence tends to be convex, focal mass near scar
            • May be hypervascular on Doppler
        • Focal breast pain
          • 0.3% of women with focal pain found to have malignancy; not indicated for work-up of nonfocal/diffuse breast pain
      • US Not Appropriate

        • Not a substitute for mammographic screening unless patient unable to cooperate (e.g., some disability patients)
        • Assessing chest wall invasion
          •  Posterior shadowing obscures evaluation
        • Saline breast implant integrity: Clinical diagnosis
        • Silicone breast implant integrity better assessed by MR
          • US low sensitivity for uncollapsed rupture
            • Folds can mimic rupture
          • Particularly poor for double-lumen implants
          • Pathognomonic appearance of siliconoma on US ("snowstorm") can be helpful in documenting extracapsular silicone

      IMAGING

      • Anatomy-Based Imaging Issues

        Selected References

        1. Barr RG et al: Diagnostic performance and accuracy of the 3 interpreting methods of breast strain elastography: a systematic review and meta-analysis. J Ultrasound Med. ePub, 2018
        2. Chen Y et al: Value of mammography for women 30-39 years old presenting with breast symptoms. AJR Am J Roentgenol. 211(6):1416-24, 2018
        3. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Breast Imaging of Pregnant and Lactating Women. J Am Coll Radiol. 15(11S):S263-S275, 2018
        4. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Breast Pain. J Am Coll Radiol. 15(11S):S276-S282, 2018
        5. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Evaluation of the Symptomatic Male Breast. J Am Coll Radiol. 15(11S):S313-S320, 2018
        6. Jung I et al: Ultrasonography-guided 14-gauge core biopsy of breast: results of 7 yrs of experience. Ultrasonography. 37(1):55-62, 2018
        7. Kushwaha AC et al: Overutilization of healthcare resources for breast pain. AJR Am J Roentgenol. 211(1):217-23, 2018
        8. Tagliafico AS et al: A prospective comparative trial of adjunct screening with tomosynthesis or ultrasound in women with mammography-negative dense breasts (ASTOUND-2). Eur J Cancer. 104:39-46, 2018
        9. Vourtsis A and Berg WA: Breast density implications and supplemental screening. Eur Radiol. ePub, 2018
        10. Moy L et al: ACR Appropriateness Criteria® Palpable Breast Masses. J Am Coll Radiol. 14(5S):S203-S224, 2017
        11. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer. J Am Coll Radiol. 14(11S):S462-S475, 2017
        12. Knabben L et al: Breast cancer and pregnancy. Horm Mol Biol Clin Investig. 32(1), 2017
        13. Parker S et al: Spectrum of pregnancy- and lactation-related benign breast findings. Curr Probl Diagn Radiol. 46(6):432-40, 2017
        14. Xue Y et al: Value of shear wave elastography in discriminating malignant and benign breast lesions: A meta-analysis. Medicine (Baltimore). 96(42):e7412, 2017
        15. Berg WA: Current status of supplemental screening in dense breasts. J Clin Oncol. ePub, 2016
        16. Berg WA et al: Ultrasound as the primary screening test for breast cancer: analysis from ACRIN 6666. J Natl Cancer Inst. 108(4), 2016
        17. Monticciolo DL et al: Six-Month Short-Interval Imaging Follow-Up for Benign Concordant Core Needle Biopsy of the Breast: Outcomes in 1444 Cases With Long-Term Follow-Up. AJR Am J Roentgenol. 1-6, 2016
        18. Moon HJ et al: Short-term follow-up in 6 months is unnecessary for asymptomatic breast lesions with benign concordant results obtained at ultrasonography-guided 14-gauge core needle biopsy. Am J Surg. 211(1):152-8, 2016
        19. Bahl M et al: Diagnostic value of ultrasound in female patients with nipple discharge. AJR Am J Roentgenol. 205(1):203-8, 2015
        20. Berg WA et al: Quantitative maximum shear wave stiffness of breast masses as a predictor of histopathologic severity. AJR Am J Roentgenol. 205(2):448-55, 2015
        21. Berg WA et al: Technologist-performed handheld screening breast US imaging: how is it performed and what are the outcomes to date? Radiology. 272(1):12-27, 2014
        22. Lehman CD et al: Imaging management of palpable breast abnormalities. AJR Am J Roentgenol. 203(5):1142-53, 2014
        23. Spick C et al: Diagnostic utility of second-look ultrasound for breast lesions identified at MR imaging: systematic review and metaanalysis. Radiology. 273(2):401-9, 2014
        24. Hooley RJ et al: Breast ultrasonography: state of the art. Radiology. 268(3):642-59, 2013
        25. Mendelson EB et al: Breast Imaging Reporting and Data System, BI-RADS: Ultrasound. 2nd ed. Reston: American College of Radiology, 2013
        26. Berg WA et al: Detection of breast cancer with addition of annual screening ultrasound or a single screening MRI to mammography in women with elevated breast cancer risk. JAMA. 307(13):1394-404, 2012
        27. Cho N et al: Distinguishing benign from malignant masses at breast US: combined US elastography and color doppler US--influence on radiologist accuracy. Radiology. 262(1):80-90, 2012
        28. Giess CS et al: Risk of malignancy in palpable solid breast masses considered probably benign or low suspicion: implications for management. J Ultrasound Med. 31(12):1943-9, 2012
        29. Hooley RJ et al: Screening US in patients with mammographically dense breasts: initial experience with Connecticut Public Act 09-41. Radiology. 265(1):59-69, 2012
        30. Lehman CD et al: Accuracy and value of breast ultrasound for primary imaging evaluation of symptomatic women 30-39 years of age. AJR Am J Roentgenol. 199(5):1169-77, 2012
        31. Abe H et al: MR-directed ("Second-Look") ultrasound examination for breast lesions detected initially on MRI: MR and sonographic findings. AJR Am J Roentgenol. 194(2):370-7, 2010
        32. Berg WA et al: Cystic breast masses and the ACRIN 6666 experience. Radiol Clin North Am. 48(5):931-87, 2010
        33. Loving VA et al: Targeted ultrasound in women younger than 30 years with focal breast signs or symptoms: outcomes analyses and management implications. AJR Am J Roentgenol. 195(6):1472-7, 2010
        34. Demartini WB et al: Utility of targeted sonography for breast lesions that were suspicious on MRI. AJR Am J Roentgenol. 192(4):1128-34, 2009
        35. Meissnitzer M et al: Targeted ultrasound of the breast in women with abnormal MRI findings for whom biopsy has been recommended. AJR Am J Roentgenol. 193(4):1025-9, 2009
        36. Alvarez S et al: Role of sonography in the diagnosis of axillary lymph node metastases in breast cancer: a systematic review. AJR Am J Roentgenol. 186(5):1342-8, 2006
        37. Berg WA et al: Operator dependence of physician-performed whole-breast US: lesion detection and characterization. Radiology. 241(2):355-65, 2006
        38. Dillon MF et al: The accuracy of ultrasound, stereotactic, and clinical core biopsies in the diagnosis of breast cancer, with an analysis of false-negative cases. Ann Surg. 242(5):701-7, 2005
        39. Berg WA et al: Diagnostic accuracy of mammography, clinical examination, US, and MR imaging in preoperative assessment of breast cancer. Radiology. 233(3):830-49, 2004
        40. Berg WA: Supplemental screening sonography in dense breasts. Radiol Clin North Am. 42(5):845-51, vi, 2004
        41. Berg WA: Rationale for a trial of screening breast ultrasound: American College of Radiology Imaging Network (ACRIN) 6666. AJR Am J Roentgenol. 180(5):1225-8, 2003
        42. Soo MS et al: Sonographic detection and sonographically guided biopsy of breast microcalcifications. AJR Am J Roentgenol. 180(4):941-8, 2003
        43. Dennis MA et al: Breast biopsy avoidance: the value of normal mammograms and normal sonograms in the setting of a palpable lump. Radiology. 219(1):186-91, 2001
        44. Stavros AT et al: Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology. 196(1):123-34, 1995
        Related Anatomy
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        Related Differential Diagnoses
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        References
        Tables

        Tables

        KEY FACTS

        • Imaging

          • Clinical Issues

            TERMINOLOGY

            • Synonyms

              • Sonography
            • Definitions

              • Targeted US: Directed to area of clinical, mammographic, MR, or other imaging abnormality
              • MR-directed US: Directed to abnormality on MR
              • Automated breast US: Typically 3D acquisition obtained in axial plane and reconstructed in coronal plane
              • Spatial compounding: Averaging of signal from multiple (usually off-angle) beams to reduce noise
                • Loss of posterior features
              • Harmonic imaging: Insonates tissue at 1 frequency; receives at multiples of that frequency (usually 2x, e.g., 12 → 24 MHz)
                • Preserves posterior features; reduces noise
              • Elastography: Method to measure stiffness of lesion and surrounding tissue
                • Downgrade soft BI-RADS 4A masses to surveillance and upgrade hard BI-RADS 3 masses to biopsy to ↑ specificity of breast US
            • General Performance Statistics

              • Not limited by breast density
              • ↓ performance in very large breasts (> 4-cm thick) and deep lesions
              • Invasive ductal carcinoma (IDC)
                • 96% sensitivity across series (range: 95-97%) vs. 84% for mammography (range: 81-89%)
              • Invasive lobular carcinoma (ILC)
                • 88% sensitivity across series (range: 68-98%) vs. 71% for mammography (range: 34-92%)
              • DCIS: Wide range of sensitivities, depending on gold standard: ~ 50% in most scenarios
            • Indications

              • Palpable abnormality
                • In combination with mammography: 97.3% sensitivity; 99.4% negative predictive value (NPV) across 9 series
                • Opportunity for direct real-time correlation of imaging and clinical findings
                • Normal fatty lobulation is common source of palpable concern
                • Layer of subcutaneous fat focally thins → underlying dense tissue palpable
                • Use US as initial test for women < 30 years or for those who are pregnant or lactating
                  • Mammogram often done initially for women ≥ 30 years, certainly if ≥ 40 years, if not pregnant or lactating
                    • Sensitivity of mammography at site of symptoms 78% vs. 98% for US
                    • Supplemental cancer detection rate (CDR) of mammography after US in women with symptoms 2/1,000 age 30-39
                  • US has greater sensitivity than mammography until ~ age 45
              • Mammographic abnormality
                • Mass, asymmetry, architectural distortion; further evaluation, guided biopsy if needed
              • Guide biopsy
                • ↑ accuracy in sampling palpable masses
                  • < 2% miss for US-guided core needle biopsy (CNB) vs. 13% without US guidance; 91% definitive
                • Inflammatory breast cancer: Identify mass, biopsy
                • Nonpalpable masses, US-guided 14-gauge CNB is sufficient in vast majority
                  • Definitive result in 93% across series; 2% false-negative rate
                  • Poor performance for fine-needle aspiration biopsy (FNAB): 77% overall accuracy, 10% insufficient
                • Suspicious Ca⁺⁺ visible on US
                  • US-visible Ca⁺⁺: More likely malignant, more likely invasive carcinoma; specimen x-ray needed on biopsy
                  • Benefit to obtaining more material: Possible indication for vacuum-assisted US biopsy
                • Targeted US after MR: Highly variable performance
                  • Average 58% success (range: 23-71%)
                    • Average 81% (range: 58-100%) of invasive cancers seen
                    • Average 50% (range: 20-100%) of DCIS identified
                    • Average 52% (range: 16-71%) of benign lesions found
                    • 66% of all masses and 33% of nonmass enhancement (NME) seen: 50% of masses ≤ 5 mm, 56% if 6-10 mm, 73% if 11-15 mm, 86% if > 15 mm
                  • Average 12% (range: 6-28%) malignancy rate among lesions not seen on targeted US: Need for MR-guided biopsy
              • Pathologic nipple discharge
                • 93% sensitivity to cause of discharge vs. 68% for galactography (2 series)
                • Central papilloma is most common cause; 56-80% sensitivity for US vs. 15-32% for mammography
              • Guide aspiration
                • Aspirate cysts only if painful to patient and requested (BI-RADS 2) or if diagnostic uncertainty (BI-RADS 4)
                  • Round, tense cysts most likely to be symptomatic
                • Aspirate/drain breast abscess: Drain can be placed
              • Guide localization for surgery
                • Provide depth ± wire or seed localization; mark overlying skin (optional)
            • US Appropriate

              • Supplemental screening in dense breasts: Handheld or automated
                • After mammography, average CDR 2.8 per 1,000
                • CDR 1-2/1,000 after tomosynthesis (studies ongoing)
                • CDR 4.8-13 cancers per 1,000 high-risk women screened
                • Same incremental CDR for prevalence and incidence screens
                • 88% of cancers seen only on screening US are invasive; median size 10 mm; 85% are node (-); ↑ detection of ILC
                • Average 3.3% risk of US-induced biopsy
                • Average 10% of biopsies prompted only by US prove malignant (range: 5-31%)
                • Performed by physician or technologist
              • Extent of disease in breast
                • Of breasts suspected to have unifocal cancer on mammography and clinically, ~ 48% have additional tumor foci at histopathology
                • Combined mammogram + US depicts ~ 90% of all tumor foci
                • May underestimate tumor size, especially if > 2-3 cm
              • Axillary nodal staging
                • Node can be identified and sampled using FNAB or CNB: Sensitivity 71% for metastasis, specificity 100%
                • Axillary nodal US and biopsy is indicated when mastectomy or neoadjuvant chemotherapy is planned or if palpable suspicious node(s) are present
                • For lumpectomy, no palpable nodes, surgeons may plan only sentinel lymph node excision
                  • Preoperative node biopsy is not indicated
              • Intraoperative US: May help achieve clear margins
              • Distinguishing recurrence from scar
                • Lumpectomy scar should ↓ over time, extend to skin incision
                • Recurrence tends to be convex, focal mass near scar
                  • May be hypervascular on Doppler
              • Focal breast pain
                • 0.3% of women with focal pain found to have malignancy; not indicated for work-up of nonfocal/diffuse breast pain
            • US Not Appropriate

              • Not a substitute for mammographic screening unless patient unable to cooperate (e.g., some disability patients)
              • Assessing chest wall invasion
                •  Posterior shadowing obscures evaluation
              • Saline breast implant integrity: Clinical diagnosis
              • Silicone breast implant integrity better assessed by MR
                • US low sensitivity for uncollapsed rupture
                  • Folds can mimic rupture
                • Particularly poor for double-lumen implants
                • Pathognomonic appearance of siliconoma on US ("snowstorm") can be helpful in documenting extracapsular silicone

            IMAGING

            • Anatomy-Based Imaging Issues

              Selected References

              1. Barr RG et al: Diagnostic performance and accuracy of the 3 interpreting methods of breast strain elastography: a systematic review and meta-analysis. J Ultrasound Med. ePub, 2018
              2. Chen Y et al: Value of mammography for women 30-39 years old presenting with breast symptoms. AJR Am J Roentgenol. 211(6):1416-24, 2018
              3. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Breast Imaging of Pregnant and Lactating Women. J Am Coll Radiol. 15(11S):S263-S275, 2018
              4. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Breast Pain. J Am Coll Radiol. 15(11S):S276-S282, 2018
              5. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Evaluation of the Symptomatic Male Breast. J Am Coll Radiol. 15(11S):S313-S320, 2018
              6. Jung I et al: Ultrasonography-guided 14-gauge core biopsy of breast: results of 7 yrs of experience. Ultrasonography. 37(1):55-62, 2018
              7. Kushwaha AC et al: Overutilization of healthcare resources for breast pain. AJR Am J Roentgenol. 211(1):217-23, 2018
              8. Tagliafico AS et al: A prospective comparative trial of adjunct screening with tomosynthesis or ultrasound in women with mammography-negative dense breasts (ASTOUND-2). Eur J Cancer. 104:39-46, 2018
              9. Vourtsis A and Berg WA: Breast density implications and supplemental screening. Eur Radiol. ePub, 2018
              10. Moy L et al: ACR Appropriateness Criteria® Palpable Breast Masses. J Am Coll Radiol. 14(5S):S203-S224, 2017
              11. Expert Panel on Breast Imaging et al: ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer. J Am Coll Radiol. 14(11S):S462-S475, 2017
              12. Knabben L et al: Breast cancer and pregnancy. Horm Mol Biol Clin Investig. 32(1), 2017
              13. Parker S et al: Spectrum of pregnancy- and lactation-related benign breast findings. Curr Probl Diagn Radiol. 46(6):432-40, 2017
              14. Xue Y et al: Value of shear wave elastography in discriminating malignant and benign breast lesions: A meta-analysis. Medicine (Baltimore). 96(42):e7412, 2017
              15. Berg WA: Current status of supplemental screening in dense breasts. J Clin Oncol. ePub, 2016
              16. Berg WA et al: Ultrasound as the primary screening test for breast cancer: analysis from ACRIN 6666. J Natl Cancer Inst. 108(4), 2016
              17. Monticciolo DL et al: Six-Month Short-Interval Imaging Follow-Up for Benign Concordant Core Needle Biopsy of the Breast: Outcomes in 1444 Cases With Long-Term Follow-Up. AJR Am J Roentgenol. 1-6, 2016
              18. Moon HJ et al: Short-term follow-up in 6 months is unnecessary for asymptomatic breast lesions with benign concordant results obtained at ultrasonography-guided 14-gauge core needle biopsy. Am J Surg. 211(1):152-8, 2016
              19. Bahl M et al: Diagnostic value of ultrasound in female patients with nipple discharge. AJR Am J Roentgenol. 205(1):203-8, 2015
              20. Berg WA et al: Quantitative maximum shear wave stiffness of breast masses as a predictor of histopathologic severity. AJR Am J Roentgenol. 205(2):448-55, 2015
              21. Berg WA et al: Technologist-performed handheld screening breast US imaging: how is it performed and what are the outcomes to date? Radiology. 272(1):12-27, 2014
              22. Lehman CD et al: Imaging management of palpable breast abnormalities. AJR Am J Roentgenol. 203(5):1142-53, 2014
              23. Spick C et al: Diagnostic utility of second-look ultrasound for breast lesions identified at MR imaging: systematic review and metaanalysis. Radiology. 273(2):401-9, 2014
              24. Hooley RJ et al: Breast ultrasonography: state of the art. Radiology. 268(3):642-59, 2013
              25. Mendelson EB et al: Breast Imaging Reporting and Data System, BI-RADS: Ultrasound. 2nd ed. Reston: American College of Radiology, 2013
              26. Berg WA et al: Detection of breast cancer with addition of annual screening ultrasound or a single screening MRI to mammography in women with elevated breast cancer risk. JAMA. 307(13):1394-404, 2012
              27. Cho N et al: Distinguishing benign from malignant masses at breast US: combined US elastography and color doppler US--influence on radiologist accuracy. Radiology. 262(1):80-90, 2012
              28. Giess CS et al: Risk of malignancy in palpable solid breast masses considered probably benign or low suspicion: implications for management. J Ultrasound Med. 31(12):1943-9, 2012
              29. Hooley RJ et al: Screening US in patients with mammographically dense breasts: initial experience with Connecticut Public Act 09-41. Radiology. 265(1):59-69, 2012
              30. Lehman CD et al: Accuracy and value of breast ultrasound for primary imaging evaluation of symptomatic women 30-39 years of age. AJR Am J Roentgenol. 199(5):1169-77, 2012
              31. Abe H et al: MR-directed ("Second-Look") ultrasound examination for breast lesions detected initially on MRI: MR and sonographic findings. AJR Am J Roentgenol. 194(2):370-7, 2010
              32. Berg WA et al: Cystic breast masses and the ACRIN 6666 experience. Radiol Clin North Am. 48(5):931-87, 2010
              33. Loving VA et al: Targeted ultrasound in women younger than 30 years with focal breast signs or symptoms: outcomes analyses and management implications. AJR Am J Roentgenol. 195(6):1472-7, 2010
              34. Demartini WB et al: Utility of targeted sonography for breast lesions that were suspicious on MRI. AJR Am J Roentgenol. 192(4):1128-34, 2009
              35. Meissnitzer M et al: Targeted ultrasound of the breast in women with abnormal MRI findings for whom biopsy has been recommended. AJR Am J Roentgenol. 193(4):1025-9, 2009
              36. Alvarez S et al: Role of sonography in the diagnosis of axillary lymph node metastases in breast cancer: a systematic review. AJR Am J Roentgenol. 186(5):1342-8, 2006
              37. Berg WA et al: Operator dependence of physician-performed whole-breast US: lesion detection and characterization. Radiology. 241(2):355-65, 2006
              38. Dillon MF et al: The accuracy of ultrasound, stereotactic, and clinical core biopsies in the diagnosis of breast cancer, with an analysis of false-negative cases. Ann Surg. 242(5):701-7, 2005
              39. Berg WA et al: Diagnostic accuracy of mammography, clinical examination, US, and MR imaging in preoperative assessment of breast cancer. Radiology. 233(3):830-49, 2004
              40. Berg WA: Supplemental screening sonography in dense breasts. Radiol Clin North Am. 42(5):845-51, vi, 2004
              41. Berg WA: Rationale for a trial of screening breast ultrasound: American College of Radiology Imaging Network (ACRIN) 6666. AJR Am J Roentgenol. 180(5):1225-8, 2003
              42. Soo MS et al: Sonographic detection and sonographically guided biopsy of breast microcalcifications. AJR Am J Roentgenol. 180(4):941-8, 2003
              43. Dennis MA et al: Breast biopsy avoidance: the value of normal mammograms and normal sonograms in the setting of a palpable lump. Radiology. 219(1):186-91, 2001
              44. Stavros AT et al: Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology. 196(1):123-34, 1995