The investigators hypothesis is that the combined use of elastography and color doppler ultrasonography can increase positive-predictive value of breast screening with ultrasound.

• Asymptomatic women who undergo breast screening with ultrasound and has breast masses of Breast Imaging Reporting and Data System (BI-RADS) category 3 or higher will be examined with conventional B-mode US as well as combined elasto-doppler US by breast radiologists.
• The likelihood of malignancy and BI-RADS category of the breast masses are assessed for each dataset of B-mode US alone and B-mode US with elasto-doppler US, respectively.
• Reference standard: Biopsy or 1 year of follow-up examination.
• The positive-predictive value, sensitivity, specificity, and diagnostic accuracy (assessed by the area under the receiver operating characteristic curve) are evaluated and compared between B-mode US alone and B-mode US with elasto-doppler US.

Inclusion Criteria:

• Women aged 30 years or older screened with breast ultrasound without specific symptoms
• Women who underwent mammography within 3 months which showed no abnormality except for dense breast
• Women who had at least one breast mass of BI-RADS category 3 or higher.

Exclusion Criteria:

• Women with breast implants
• Women who are unwilling or unable to provide informed consent
• Lesions larger than 3 cm
• Lesions that are previously noted and followed-up in the same hospital

Population will consist of asymptomatic women who visit the hospital for breast screening.

The sites are located in 4 cities of South Korea.