Synopsis
Develop the ability to select breast imaging according to the clinical question, age and physiological context while recognising each modality’s limitations and the need for image-guided resolution, while explaining uncertainty and arranging reliable review.
- Use ultrasound first in women under 40 and during pregnancy or lactation; target the palpable or axillary site and use ultrasound to guide a needle when it displays the lesion.
- Use mammography first from age 40, adding ultrasound as indicated. Perform mammography at any age for confirmed malignancy and for a U4 or U5 lesion, preferably before biopsy; consider it below 40 for P4 or P5 clinical findings.
- Use dynamic contrast-enhanced MRI for defined oncological questions such as selected local staging, lobular extent, mammographically occult cancer or an occult breast primary, rather than as a generic superior test.
Reasoning priorities
Resolve a focal palpable, inflammatory or axillary question and guide intervention.
Correlate the transducer finding with the exact clinical site; a benign incidental lesion elsewhere does not explain a separate palpable abnormality.
Worked reasoning
A 34-year-old pregnant patient has a new hard 2 cm breast mass. They are worried that any imaging could harm the fetus and ask to wait until after delivery.
- Define and map the mass clinically, document gestation and explain that pregnancy changes test selection but does not justify delaying diagnosis of a suspicious lesion.
- Request targeted breast and axillary ultrasound first, using it to characterise the palpable target and provide a route for image-guided core biopsy.
- If ultrasound is U4 or U5, complete mammography preferably before biopsy; perform mammography irrespective of age once malignancy is confirmed, without presenting abdominal shielding as routinely necessary.
- Avoid substituting breast MRI for tissue diagnosis during pregnancy. Current RCR guidance advises against pregnancy MRI because background enhancement reduces sensitivity; seek specialist radiology input only for an exceptional unresolved question.
- Verify that imaging and core sampled the same coordinates, and ensure the result reaches both breast and obstetric teams with a named next appointment.