Ultrasound of the Breast Part 1 Cross-Sectional Anatomy Holdorf

BI-RADS Breast Imaging-Reporting and Data System (ACR) Assessment Codes: 0 Incomplete 1 Negative 2 Benign findings (100%) CYST 3 Probably benign (< 2% chances of cancer) 4 Suspicious (3-94% chance of cancer) Sub cats 5 Highly suggestive of malignancy (> 95%) 6 Known biopsy proven cancer

Mammography Reports BI-RADS Recommendations 0 Needs additional imaging evaluation (incomplete study) Annual screening (> 40 yearly) Annual screening Short-term follow-up (usually 6 months) Tissue sampling is required Definitive treatment required (biopsy or surgery) Definitive treatment required

Sub cats for BI-RAD 4 4A: low suspicion for malignancy 4B: intermediate suspicion of malignancy 4C: moderate concern, but not classic for malignancy

Breast Composition Categories 1: Almost entirely fatty 2: Scattered fibro-glandular densities 3: Heterogeneously dense 4: Extremely dense

The Breast is a modified sweat gland located in the superficial fascia of the anterior chest wall.

The major portion of the breast tissue is situated between the second or third rib superiorly… the sixth or seventh costal cartilage inferiorly… the anterior axillary line laterally… and the sternal border medially.

In many women, the breast extends deep toward the lateral upper margin of the chest and into the axilla. This extension (the axillary tail of the breast) is referred to as the tail of Spence. Actually, the breast is TEAR SHAPED.

The tail of Spence

The surface of the breast is dominated by the nipple and the surrounding areola.

A few women may have ectopic breast tissue or accessory (supernumerary) nipples.

Ectopic breast tissue and accessory nipples are usually located along the mammary milk line, which extends superiorly from the axilla downward and medially in the oblique line to the symphysis pubis of the pelvis.

Sonographically, the breast is divided into three layers: Sonographically, the breast is divided into three layers: The subcutaneous layer-8 The mammary (glandular) layer-9 the retro-mammary layer-10

The subcutaneous and retromammary layers are usually quite thin and consists of fat surrounded by connective tissue speta.

The fatty tissue appears hypoechoic while the ducts, glands, and supporting ligaments appear echogenic.

The mammary/glandular layer includes the functional portion of the breast and the surrounding supportive (stromal) tissue.

The lobes emanate from the nipple in a pattern resembling the spokes of a wheel.

The upper-outer quadrant of the breast contains the highest concentration of lobes.

This concentration of lobes in the upper-outer quadrant of the breast is the reason a majority of tumors are found there.

Connective tissue septa are collectively called Cooper’s ligaments.

Muscles sonographically appear as a hypoechoic interface between the retromammary layer of the breast and the ribs.

Subcutaneous fat generally appears hypoechoic, whereas Cooper’s ligaments and other connective tissue appear echogenic and are dispersed in a linear pattern.

The mammary/glandular layer lies between the subcutaneous fatty layer anteriorly and the retromammary layer posteriorly.

The ribs sonographically appear as hyperechoic rounded structures with dense posterior shadowing.

The size and shape of the breast varies remarkably from woman to woman The size and shape of the breast varies remarkably from woman to woman. The size and shape of the breast varies over time because of the changes that occur during the menstrual cycle, with pregnancy/breast feeding, and during menopause.

Breast Pain Cycle

Generally, in a young woman, fibrous tissue elements predominate and the resulting appearance on mammography and ultrasound is a dense, echogenic pattern of tissue.

As a woman ages, the glandular breast tissue undergoes cell death and is remodeled by the infiltration of fatty tissue.

Lymphatic drainage from all parts of the breast generally flows to the axillary lymph nodes. Only about 3% of lymph is eliminated by the internal chain, whereas 97% of lymph is removed by the axillary chain.

Physiology of the Breast The primary function of the breast is to transport fluid. The breast includes the fat, ligaments, glandular tissue, and ductal system that work together to provide a fluid transport, and only one entity in this group produces milk.

The ductal system is critical in the transport of fluids within the breast and it is also a source for ductal pathologic conditions. Ducts consist of epithellum cells, which line the interior of the ducts, and a myoepithelium set of cells, which controls the contractibility of the ducts. Milk is produced within the acini and is carried to the nipple by the ducts.

Hormones The female breast is affected by hormonal levels during each menstrual cycle and is further affected by both pregnancy and lactation.

Breast Screening The primary purpose of breast screening is the detection and diagnosis of breast cancer in its earliest and most curable stage. Breast cancer screening is recommended in women without clinical signs of breast cancer. According to the American Cancer Society, breast cancer screening involves a monthly breast self-examination (BSE), regular clinical breast examinations (CBE) by a physician or another health care provider, and an annual screening mammography.

Mammography, Sonography, and MRI are the primary imaging tools used for diagnostic breast evaluation. Mammography provides a sensitive method of screening for breast cancer, whereas ultrasound and MRI are used to provide additional characterization and further interrogation of breast lesions that are not well visualized by mammography. Ultrasound may be used for screening purposes in young, dense breasts, which are difficult to penetrate by mammography. Ultrasound is able to evaluate palpable masses that are not visible on a mammogram and to image the deep juxtathoracic tissue not normally visible by mammography.

Ultrasound is also useful in differentiating solid, round masses from fluid-filled cysts.

MRI is also a useful tool in breast imaging, but is prohibitively expensive for screening purposes.

Sonographic Evaluation of the Breast The Sonographer must have basic clinical information regarding any patient who is referred for breast ultrasound. Pertinent clinical information includes: The patient’s age Risk factors Symptoms Location of the lump Clinical impression of any breast lump

Sonography is normally used as an adjunct to mammography, but may be the initial method of imaging for the following patients: In a patient with a palpable breast lump In a young patient with dense breasts In a pregnant or lactating patient In a patient with breast augmentation In a patient with a difficult or compromised mammogram

That breast cancer is rare under age 25 The three main reasons mammography is rarely indicated for patients under age 20 are: That breast cancer is rare under age 25 That breast tissue is generally dense Young breast tissue is more sensitive to damage from radiation

Most breast masses that arise during the teen years are fibroadenomas.

Malignant breast lesions in patients under 20 years of age are extremely rare. Although Sonography is an invaluable aid to breast imaging, it should not be used as a substitute for a mammogram.

Moderate compression applied with the transducer during scanning will improve detail and decrease the depth of tissue the ultrasound beam must traverse.

Positioning: The patient is positioned with her arm behind her head on the side of the breast to be examined.

Scanning Technique: When examining for a palpable mass or for a correlation with an abnormal mammogram, some centers scan only the area of interest.

The mass is then thoroughly scanning in orthogonal planes (90 degrees apart) to evaluate the lesion in three dimensions.

This can be recorded using sagittal and transverse images or using radial/anti-radial transducer positions.

radial and anti-radial transducer positions.

Most imaging centers scan the breast not unlike a clock

Clock method-left breast

Distance from the nipple method-Lateral distance

Distance from the nipple-Depth

All dominant solid masses are generally recorded with three-dimensional measurements: Length Width Height

The distinction between a cyst and a solid mass is extremely important for management purposes.

A mass that meets the criteria of a simple cyst on ultrasound is universally considered benign - but solid masses have a malignant potential.

If a cyst has features not associated with a simple cyst, aspiration and/or biopsy should be considered.

The demonstration of increased vascular flow could accelerate the need for biopsy of this mass.

High-quality sonographic imaging of a solid breast mass is quite accurate at characterizing a lesion as probably benign or probably malignant in a majority of cases.

Benign lesions usually have smooth, rounded margins.

Malignant tumors are aggressive and tend to grow through tissue via finger-like extensions called spiculations.

Benign tumors are usually slow growing and do not invade surrounding tissue. They tend to grow horizontally within the tissue planes, parallel to the chest wall. Malignant lesions, on the other hand, tend to grow right through the normal breast tissue. Rule of thumb: Non cancerous mass - wider than tall, rubbery and compressible. Cancerous mass - taller than wide, hard and non-compressible.

Benign breast tumor/Mammography

Malignant breast tumor/Mammography

As malignant masses enlarge, they may cause retraction of the nipple or dimpling of the skin as the spiculations pull the Cooper’s ligaments.

Shape: A rounded or oval shape is usually associated with benign lesions, while sharp, angular margins are associated with malignancy.

Sharp, angular margins

Orientation: Benign lesions tend to grow within the normal tissue planes and their long axis lies parallel to the chest wall.

Orientation: Malignant lesions are able to grow through the connective tissue and may have a vertical orientation when imaging the breast from anterior to posterior.

A solid lesion that is hypoechoic relative to the normal breast parenchyma is more suspicious for malignancy.

While calcifications are not frequently visualized by Sonography, their detection in a hypoechoic mass is suspicious for malignancy.

Attenuation Effects: Enhancement behind a lesion is a characteristic associated with benign lesions.

Shadowing behind a solid breast mass is another suspicious sonographic sign for malignancy.

Mobility: Benign lesions will normally demonstrate a limited degree of mobility, whereas malignant lesions are normally very fixed or rigid in their position.

Malignant lesions are normally very hard and non-compressible.

Vascularity: Doppler interrogation of a breast lesion is an essential element of the study.

Malignant masses will often demonstrate increased vascularity Malignant masses will often demonstrate increased vascularity. Adenocarcinoma

Symptoms of a breast mass include: Pain A palpable mass Spontaneous or induced nipple discharge Skin dimpling Ulceration Nipple retraction

Skin dimpling or ulceration and nipple retraction nearly always result from cancer.

Benign tumors are rubbery, mobile, and well defined (as seen in a fibroadenoma). Malignant tumors are often stone hard.

Breast Cyst - anechoic

Complex Cyst

Breast cyst – edge shadowing and enhancement

Fibroadenoma – homogeneous and isoechoic

Cyst aspiration needle with reverberation

Calcified breast mass - shadowing