The distinction between diagnostic breast imaging for the assessment of breast symptoms and breast screening is an important one.
Screening is an assessment for women who have no breast symptoms. These women are being assessed, usually using mammography alone, with the aim of detecting breast cancer at an early stage. Women with breast symptoms are most appropriately assessed at a diagnostic imaging facility, often using both mammography and ultrasound, to provide an explanation for their symptoms and exclude breast cancer as a cause.
The sensitivity of mammography increases with increasing age. Sensitivity is improved with the addition of ultrasound over all ages though the size of this benefit is greater in women under the age of 50 years.
Given the limitations of both mammography and ultrasound, they are often used in a complementary capacity to give information in the evaluation of breast abnormalities. Mammography and ultrasound used in combination will correctly identify about 95% of breast cancers in symptomatic women. Therefore, a small but significant proportion of breast cancers will not be diagnosed on imaging alone and clinical opinion is crucial in determining whether further testing such as biopsy is needed, despite normal imaging findings.