Download Breast Ultrasonography. An Introduction Part I

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)
1 Annual screening (> 40 yearly)
2 Annual screening
3 Short-term follow-up (usually 6 months)
4 Tissue sampling is required
5 Definitive treatment required (biopsy or surgery)
6 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:
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 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 selfexamination
(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:
1.
2.
3.
4.
5.
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:
1.
2.
3.
4.
5.
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
The three main reasons mammography is rarely indicated for
patients under age 20 are:
That breast cancer is rare under age 25
2. That breast tissue is generally dense
3. Young breast tissue is more sensitive to damage from
radiation
1.
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 methodLateral 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 noncompressible.
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.
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