Imaging the Breast

Question 1

In what 4 scenarios might women be referred for breast imaging?

Answer 1

• if they are symptomatic and notice an abnormality of the breast, such as:

1. lumps / masses
2. skin changes
3. shape changes
4. nipple discharge
5. pain (rarely a sign of malignancy)

• as part of a breast screening programme (asymptomatic women)
• for surveillance after breast cancer
• for surveillance due to family history

Question 2

What is meant by the “triple assessment” for breast changes?

Answer 2

• the “triple assessment” comprises clinical examination, imaging and histology

Question 3

What are the risk factors for breast cancer?

What is the epidemiology like?

Answer 3

1. smoking
2. obesity
3. nulliparity
4. increasing age
5. late menopause
6. previous family history

• around 50,000 women are diagnosed with invasive breast cancer each year and 8/10 are >50

Question 4

Who is invited to the UK screening programme for breast cancer?

Answer 4

• asymptomatic women between 50 - 71** are invited for screening **every 3 years
• women < 50 may be screened if they are at a high risk of developing breast cancer
• women > 71 are not invited to screening, but can have screening if they wish

Question 5

What symptoms / signs would result in referral to a breast clinic for further investigation into possible breast cancer?

Answer 5

1. a lump in the breast or chest wall
2. an area of thickened breast tissue
3. change in the size / shape of one or both breasts
4. discharge from the nipple (may be streaked with blood)
5. lumps / swellings in the armpit
6. dimpling of the skin around the breasts
7. rash on or around the nipple
8. change in appearance of the nipple (becoming sunken into the breast)

pain is not usually a sign of cancer

Question 6

What are the first line techniques for imaging the breast?

Answer 6

• mammography
• ultrasound

Question 7

How does mammography work?

Answer 7

• it uses X-rays that are equivalent to a couple of months’ background radiation
• the X-rays are specialised and lower energy as normal and pathological breast tissue have similar properties
• the breast is compressed prior to taking the image

Question 8

Why is the breast compressed in mammography?

How many images are usually taken?

Answer 8

• the breast is compressed to decrease tissue thickness** and **minimise image artefact / blurring
• it is difficult to spot small lesions on mammograms due to the superimposition of strutures in a 2D image of a 3D structure
  
  • this is particularly the case in dense breasts
• taking multiple projection images of the breast from different angles allows reconstruction of a 3D image that provides more detail of breast tissue
• usually craniocaudal and mediolateral views are obtained
• tomosynthesis involves 9 views and gives more information

Question 9

What is the benefit of using digital mammography over analogue?

Answer 9

• digital mammography allows for image manipulation

Question 10

What views of the breast are shown here?

Answer 10

right mediolateral oblique and left craniocaudal views

Question 11

What is Chassaignac bursa?

Why is it important to identify?

Answer 11

• it is a lucency on the mammogram that represents connective tissue between the breast and chest wall
• it should be seen on all CC and MLO mammograms
• if it is not seen, the image is not technically adequate

Question 12

As well as the presence of Chassaignac bursa, what other technical details must be present in both CC and MLO views in order for the image to be adequate?

Answer 12

• all glandular breast tissue must be seen
• image must be correctly annotated
• no movement artefact
• no skin folds
• images should be symmetrical

Question 13

What technical details specific to CC and MLO images need to be present in order for the image to be adequate?

Answer 13

Craniocaudal view (CC):

• the nipple should be in profile and in the midline of the image

Mediolateral oblique view (MLO):

• the pectoral shadow should be seen down to the level of the nipple or lower

Question 14

When is mammography the first line investigation?

Answer 14

• for routine screening (asymptomatic women) over 35 years of age
• for symptomatic women over 35 years of age

women <35 have denser breast tissue, so USS is the first line imaging technique

Question 15

What are the advantages and disadvantages of mammography?

Answer 15

Advantages:

1. relatively cheap and quick
2. non-invasive
3. very good visualisation
4. can be used to guide biopsy (but US is usually used)

Disadvantages:

1. can be uncomfortable for some patients
2. difficult if breasts are small
3. not as effective if breast tissue is dense

Question 16

How do invasive carcinomas typically appear on a mammogram?

Answer 16

• they are spiculated
• they have poorly defined / irregular margins
• they distort the architecture of surrounding tissue

Question 18

What is shown in these images?

Answer 18

Question 19

What is meant by 3D digital tomosynthesis and why is it performed?

Answer 19

• it is difficult to spot small lesions on mammograms due to the superimposition of structures in a 2D image of a 3D structure
• it is more difficult to spot lesions in dense breasts
• taking multiple projection images of the breast from different angles allows for reconstruction into a 3D image that provides more detail of breast tissue
• an X-ray tube rotates through 50^o to obtain 9 projections

Question 20

What is the difference between these images?

Answer 20

the lesion is much easier to identify when 3D tomosynthesis is used compared to a 2D image

Question 21

When is USS used to image the breast?

Answer 21

• USS is the first line imaging technique in women <35 due to denser breast tissue
• USS is performed after mammography in women >35 to further evaluate a breast mass

Question 22

What are the advantages and disadvantages of US scanning?

Answer 22

Advantages:

1. ​relatively cheap
2. non-invasive
3. portable
4. can be used to guide biopsy
5. excellent for showing features of a mass - size, shape, fluid-filled/solid, vascularity

Disadvantages:

1. image quality is operator dependent
2. more difficult in larger patients
3. can take time

Question 23

What other structure can be evalutated with USS?

Why is this significant?

Answer 23

• the axilla can also be evaluated with USS
• lymph nodes may look suspicious for infiltration
• if so, fine needle aspiration cytology is undertaken
• if the nodes are negative on cytology then sentinel node biopsy is performed during surgery

Question 24

What are examples of benign breast lesions?

What features do they all share on US?

Answer 24

• benign lesions include fibroadenomas, lipomas and simple cysts
• they all appear as well-defined, hypoechoic lesions that are uniform in shape** with **normal vascularity

Question 25

How do cysts / complex cysts appear on US?

Answer 25

**_Cysts:_** * **well-defined** and **oval** in shape * they have **posterior acoustic enhancement** and are **_uniformally hypoechoic (black)_** as they are filled with fluid **_Complex cysts:_** * these may have **internal echoes, irregular walls** and **septations** within them

Question 26

How do fibroadenomas, abscesses and galactocoeles appear on US?

Answer 26

**_Fibroadenomas:_** * appear **well-defined** and **hypoechoic (black)** **_Galactocoeles:_** * can appear as either **simple or complex** **_Abscesses:_** * can have a varied appearance as some appear more like **simple cysts**, whereas others appear more **solid with internal echoes**

Question 27

What are the US features of malignant lesions? When do lymph nodes arouse suspicion?

Answer 27

* carcinomas appear as **_irregular masses_** (less uniform in shape) that are **_poorly defined_** * they are **hypoechoic** * they may show **posterior acoustic shadowing** * they may have **internal echoes / shadowing** or **calcifications** * colour doppler can show **_abnormal vascularity_** * they tend to be **taller** rather than wide * lymph nodes are suspicious when they are **_enlarged**_ or have _**thickened cortices_**

Question 28

How is a vacuum-assisted breast biopsy (mammotome / minimally invasive breast biopsy) performed? When is this used?

Answer 28

* a core biopsy needle is attached to a vacuum that **sucks the tissue into the needle** * a **rotating cutting device** takes the sample * it may place a **clip in-situ** for **localisation** once the procedure is finished * it uses local anaesthetic * it is suitable for **_small impalpable lesions under image guidance_**

Question 29

When does CT imaging play a role in imaging the breast?

Answer 29

* it does not play a role in the initial assessment of breast lumps / masses * it has an important role when **_breast malignancy is confirmed_**, especially if **lymph nodes are involved** or **metastatic disease** is suspected

Question 30

What are the indications for using CT to image the breast? Which regions of the body should be imaged?

Answer 30

* CT is used to **_stage disease_** when there is confirmation on **lymph node involvement** or other features suggesting **metastases** * **_CT thorax, abdomen and pelvis_** performed to look for signs of **visceral mets** * CT can be used to assess for **presence and extent of mets in the _skeleton_** * clinical suspicion of metastatic spread to other regions based on symptoms/signs can prompt imaging of that region

Question 31

In what 2 situations does MRI imaging have a role in breast imaging?

Answer 31

* contrast-enhanced MRI can be used in the **_assessment of breast tissue**_ and after _**malignancy is confirmed_**

Question 32

When is contrast-enhanced MRI used in the assessment of breast tissue?

Answer 32

* if the breasts are **_very dense_** * if the **_lesions are very small_** * if **routine imaging** (mammography and US) fails to allow **adequate evaluation** of masses * for **_screening in high-risk women_**

Question 33

When can contrast-enhanced MRI be used in confirmed malignancy?

Answer 33

* lesions rapidly take up contrast, showing **_increased vascularity_ around malignancies** * can be used in **_lobar carcinomas_**, which tend to be **multifocal** * in **axillary lymph node assessment** * to evaluate **tumour response to chemotherapy** prior to surgery and to **_detect recurrence_** * to assess **scars at lumpectomy site**s and **_differentiate scar tissue from recurrence_** * to assess **_invasion of malignancy_** (i.e. into underlying muscle) and the presence / extent of **_visceral and/or bony metastases_**

Question 35

When is nuclear medicine used in imaging the breast?

Answer 35

**_sentinel node imaging_** * **_technetium-99m_** attached to **_sulphur colloid particles_** is injected into a tumour * the particles migrate through the lymphatic system to the **nearest lymph node**, where they are **phagocytosed and retained** * this allows identification of the **_sentinel lymph nodes_** * this aids **_staging of cancer_** and allows for **planning of future surgery**

Question 36

What is bone scintigraphy? What symptoms might be present that lead to this being performed?

Answer 36

* bone scintigraphy is performed in patients to assess the **_presence / extent of bone metastases_** * metastatic spread to bone is common in breast cancer * signs / symptoms suggestive of bone metastases are **_unremitting bony pain**_ or _**pathological / low trauma fracture_**