Ultrasound of The Breast
Part 2
Holdorf PhD, MPA, RDMS (Ob/Gyn, Ab), RVT, LRT(AS)
Instrumentation
 Breast Sonography is extremely operator-dependent.
Therefore, it is essential to use appropriate equipment and
be properly schooled in breast Sonography in order to
achieve diagnostic accuracy.
 Sonographic images are created using the B-Mode
(brightness) principle. This offers a gray scale image of the
breast.
 The set-up of the ultrasound system (machine) should
include selecting the most appropriate transducer and
optimizing the depth, overall gain, TGC, output power,
focus, and gray scale. Color and power Doppler techniques
continue to play a useful role in breast imaging and also
require fine adjustment.
Transducers
 Transducer selection is critical in breast imaging.
 Frequency
 A 10.0 – 18.0 MHz frequency is optimal
 Need high frequency probe for superior axial and lateral
resolution (detail) while maintaining penetration to
chest wall.
 A broadband transducer (wide frequency range) is
optimal.
 Trade-off; High frequency probes yield superior image
detail while losing penetration ability. Low frequency
probes penetrate deeper but lose image detail.
Probe Design
 A linear Array transducer is optimal.
 Produces a rectangular image
 Allows direct contact scanning perpendicular to the chest
wall.
 Accurate measurements can be recorded by avoiding beam
divergence artifact (this is achieved with a rectangular image
vs. a sector image).
 Interventional procedures (i.e., cyst aspiration, biopsy, and
needle localization, etc.) can be accurately guided with a
linear array probe.
 A curved Array transducer may be used to supplement the
sonographic examination if a mass is too large to fit on a
linear image.
 Using the lower frequency curved array probe provides a
larger field of view at the expense of lost resolution.
Depth
 Depth should be sufficient to visualize the breast
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tissue from skin to chest wall. Breast size will vary from
one patient to the next. However, an imaging depth
between 3 and 6 cm should be adequate.
Imaging of the breast should include
1. skin
2. breast parenchyma
3. pectoral muscle
4. chest wall
Gain
 Receiver gain is the amount of amplification applied to a
returning echo. An echo’s brightness is controlled by gain.
Gain is the most frequently adjusted control. It is
optimized for each patient depending on several factors.
These factors include breast size, thickness, and tissue
density.
 There are typically three adjustments for gain on the
ultrasound control panel:
 1. Overall Gain
 2. TGC
 3. Auto Gain Optimization
 OVERALL GAIN
 Controls the level of brightness of all echoes appearing on the
image. The Sonographer has the ability to increase or
decrease the overall brightness by using this control.
TGC (Time Gain Compensation)
 Allows for brightness to be controlled at varying
depths throughout the image. The top control adjusts
brightness in the near field of the image. The bottom
controls adjust brightness in the far field.
Output Power
 Output power is the amount of voltage applied to the
transducer to create a sound wave. This control
determines the patient’s exposure to ultrasound
energy. Therefore, the sonogphaer should consider
prudent use of output power. All state-of-the-art
sonographic systems, however, function at a safe power
setting while operating at 100% output power.
 Sonographers should remember the ALARA principle:
 Output power should be set “As low as reasonably
achievable.”
Focus
 Multi-focus
or variable (Adjustable) electronic
focusing will achieve optimal breast detail.
 The use of multiple focal zones will provide excellent
resolution of full depth of the image. This may
significantly reduce the frame rate. Multiple focal
zones, however, are still recommended.
 Trade-off: Multiple focal zones will yield the best
resolution throughout the entire image at the expense
of a slow frame rate.
 Increased focal zones = decreased frame rate.
Multiple focal zones
Single focal zone (single focus)
Gray Scale
 Echoes returning from breast tissue are assigned to a
specific shade of gray based on their echo strength. This
function of the ultrasound system is known as Gray Scale
Mapping or Dynamic Range. The sonographer controls the
selection of the gray scale map or dynamic range by using
the breast or small part examination preset or protocol
control. Fine adjustments to the dynamic range may also be
made during scanning.
 Generally for Breast imaging, a broad gray scale map or
dynamic range is used. This provides a wide range of gray
shades to be displayed while demonstrating subtle tissue
differences. A map with too few gray shades may not
accurately demonstrate low-level echoes within a cyst or
solid lesion.
Artifacts
 Artifacts exist in breast sonography as they do imaging
any other organ structure. Some artifacts have proven
helpful and may aid in determining certain
characteristics about tissue. Artifacts also hinder
imaging capabilities.
 Helpful artifacts
 Acoustic enhancement – Generally associated with a
cystic/benign lesion.
 Shadowing – generally associated with a solid/malignant
lesion.
Shadowing artifact with breast
cancer
Unwanted artifacts
 Reverberation – artifactual linear echoes parallel to a strong
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interface. Has a distinct “stepladder” or “venetian blind”
appearance.
Side or Grating lobe – Secondary sound sources off the main
sound beam that place artifactual echoes within a cyst.
Slice (section) Thickness – Unwanted echoes from the thickness
of the sound beam in the elevation plane that place artifacts
within a cyst.
Nipple Shadowing – shadowing in the subareolar region may be
eliminated by angling the transducer posterior to the nipple or
by using the “rolled nipple” technique.
Volume Averaging – decreases contrast resolution and spatial
resolution (both axial and lateral). Places unwanted echoes in
cysts.
 Doppler is helpful in distinguishing:
 Solid vs. Cystic – Positive flow within a lesion confirms a solid
nature.
 Inflamed vs. non-inflamed tissue- Doppler signal will
increase due to increased flow to an inflammation.
 Complicated Cyst vs. complex cyst – vs. intraductal papilloma
– Doppler signal will be absent in the debris of a complicated
cyst but may be evident within the solid component of a
complex cyst or intraductal papilloma.
 PRESSURE: Minimal transducer pressure should be used with
Doppler scanning techniques of the breast. The small vessels
within the breast tissue are easily compressed.
 Doppler technique: In order to optimize Doppler
imaging, the sonographer should establish a technique
for low velocity flow states:
 This includes
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1. Low velocity Scale
2. Low filter setting
3. Optimal Doppler Gain Setting
4. Increased PRF for high flow velocities.
Solid or Cystic? Conventional color Doppler reveals solid mass
Elastography
 Elastography is a diagnostic method that evaluates the
elastic properties of tissue. Breast tissues and masses
vibrate or compress differently based on their firmness.
 It is well known that breast fat is highly elastic and
compresses significantly. It is also known that benign
lesions tend to be soft (compressible) and malignant
lesions tend to be hard (very firm and non-compressible.
 Therefore, elastography may have the potential to
differentiate benign from malignant breast tumors
(distinguish BIRADS 3 form BIRADS 4 lesions) and
potentially reduce the number of biopsies.
Skin
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The skin is composed of the epidermis and dermis layers
The thickness is 0.5 to 2 mm
It is slightly thicker in young females and thins with age.
NIPPLE
 Consists of dense connective tissue and erectile muscle.
 It contains many sensory nerve endings.
 15 to 20 collecting (lactiferous) duct openings may be seen
(each of which arise from a breast lobe)
 AREOLA
 Circular area of dark pigmentation seen around the nipple.
 Consists of smooth muscle.
 Slightly thicker than surrounding skin.
 Contains Montgomery glands- sebaceous glands seen as small
bumps in the areola.
 1. Subcutaneous (Premammary Layer)
 2. Superficial layer
 3. Deep layer
 4. Superficial fascia
 5. Mammary Layer
Subcutaneous (Premammary )
Layer
 Lies just beneath the skin extending to the mammary
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layer
Consists primarily of fat
It is not seen posterior to the nipple
Amount of fat increases with age, pregnancy, and
obesity
Cooper’s ligaments appear as prominent structures
within the subcutaneous layer.
Standard Anatomic Reference
 Quadrant Method
 Each breast can be divided into quadrants (4):
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UO – Upper Outer
UI – Upper Inner
LO- Lower Outer
LI – Lower Inner
Glandular tissue is usually thicker in the Upper-Outer
quadrant of both breasts
Therefore, a larger percentage of cancers are found there.
Clock method
 Regions of the breast are correlated with positions of a
clock. This method allows a more precise location to
be documented.
 Correlating clock locations from right to left side is
important in evaluating the breast for symmetry. For
example, the 10:00 position in the right breast
correlates with the 2:00 position on the left.
Development Anomalies
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Amastia- absence of one or both breasts
Polymastia – accessory breast or more than two breasts.
Athelia- absence of the nipple.
Polythelia – accessory nipple (most common breast
anomaly).
 Amazia- absence of the breast tissue with development of
the nipple.
 Nipple flattening or Nipple inversion.
 Unilateral early ripening – asymmetric growth of the
breasts.
 Polythelia is more common in men than in women.
Intra-mammary Lymph Node
 Approximately 75% of lymphatic drainage is to the axilla.
Therefore, the axillary lymph node chain becomes
extremely important in predicting the spread of breast
cancer.
The axillary lymph node chain consists of 6 groups of nodes:
 1. External mammary group-located along the lateral
thoracic vessels.
 2. Scapular group-run with the subscapular vessels.
 3. Axillary group- run with the axillary vessels.
 4. Central group – run with the axillary vessels
 5. Subclavicular group – run with the subclavian vessels.
 6.Interpectoral (Rotter’s) nodes – found between pectoralis
major and minor muscles.
Lymph nodes of the axillary region
Mature female breast
 The mature female breast is sensitive to the menstrual
cycle and responds to fluctuating hormone levels
every month. Early in the proliferative phase of the
menstrual cycle, changes in the epithelium occur.
Later in the secretory phase, the ducts and veins
increase in size, the stroma becomes edematous, and
the epithelium produces secretions. These changes
may account for premenstrual breast discomfort. At
the onset of menses, the breast tissues decrease in size.
Pregnancy
 During pregnancy, there is considerable change in the
breast tissue. The TDLUs increase in size as the
epithelium begins to swell. The acinar cells enlarge in
response to a variety of hormones including estrogen
and progesterone, and lactogen, prolactin, and
chorionic gonadrotrophin from the placenta. Late in
the pregnancy, the lactiferous ducts increase in size.
Cartoons of Shapes
Sonography
Breast Sonography
 Sonography has been shown to be highly valuable in
the diagnosis and management of breast disease. The
use of breast sonography as a screening tool for breast
cancer, especially for younger patients, continues to
gain popularity. Using sonography as a screening tool
for all patients is highly debated.
 There are several approaches for using Breast
Sonography or Breast Ultrasound (BUS) in the
diagnosis of disease: Targeted Examination and Whole
Breast Examination.
Targeted Exam
 Sonography is used to evaluate a specific area of breast
only. Usually performed as a follow-up to
mammography. The entire breast and opposite breast
are not evaluated.
Whole Breast Exam
 Sonography is used to survey the entire breast for the
presence of disease, often with attention to a specific
area.
 Sonography
also plays a crucial role in the
management of breast disease. Real-time visualization
of the needle’s path using 2D or 3D/4D technique
allows sonography to guide interventional procedures.
Indications for Breast Sonography
 Characterize masses as cystic or solid
 Follow-up to Mammography
 Evaluate palpable masses in young women (less than 30) avoiding
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mammography.
Evaluate masses in pregnant and lactating women.
Evaluate dense breast tissue
Evaluate a mass seen in only one view on mammography
Evaluate inflammation
Evaluate the irradiated breast
Evaluate the augmented breast
Evaluate axillary lymph nodes
Evaluate nipple discharge
Evaluate patients when mammography is not possible
Serial evaluation of a benign mass
Evaluate the male breast
Guide interventional procedures
Patient History
 The sonographic examination begins with a through
patient history. Sonographers should use a questioning
technique to obtain as much personal history that the
patient can provide.
 Patient history should include:
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Patient’s name
Personal history of breast disease
Personal history of cancer
Family history of breast disease
Medications: especially hormones
Previous breast surgeries and findings
Breast pain and location
Findings from monthly breast self-examinations (BSE)
Findings from clinical breast examination (CBE)
 The sonographer should also make a visual inspection of
the breast for:
 Size, shape, contour, and symmetry
 Skin redness, edema, dimpling or retraction, protrusions, and
thickening.
 Nipple retraction and discharge
 Surgical scars
 If palpable lump is noted, the sonographer should
document:
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Location
Size
Shape (round, oval, lobulated, or irregular)
Consistency of lump (soft, rubbery, firm, hard, gritty)
Mobility (movable or fixed)
Distanced from the nipple
Date when it was first discovered and has it changed over
time.
 If
a previous Mammogram or BUS has been
performed, the prior examination should be reviewed
by the sonographer for comparison.
 It
is
essential
that
size,
shape,
and
density/echogenicity of a mass are consistent from one
exam to the next.
Skin dimpling
Positioning
 The patient is examined in a supine or supine-oblique
position with the ipsilateral (same) arm raised above
the head.
 A sponge or pillow may be used to support the
patient’s back. This maneuver allows a more even
distribution of the breast tissue over the chest wall
with the nipple centered.
 The thickness of the breast is minimized and allows
adequate penetration by the sound beam. This is also
identical to the position used during open excisional
biopsies.
 The right breast is best evaluated with the patient in
the LPO (left posterior oblique) position. The left
breast is best evaluated in the RPO (right posterior
oblique) position.
 The medial aspect of the breast is effectively evaluated
with the patient lying in the supine position.
 For larger breasted patients, lateral lesions may require
a steep oblique or decubitus position. A sitting or
upright position may be used as an alternative patient
position to simulate the cranio-caudal (CC)
mammographic view.
Transducer Pressure
 Moderate transducer pressure should be applied
during scanning.
 This will:
 Improve sound transmission
 Improve detail or resolution
 Decrease the tissue depth for better penetration
 May eliminate some artifacts
Scan Planes
 Sagittal and transverse scan planes may be used in
breast imaging. Sagittal and transverse scan planes
correspond to conventional sagittal and transverse to
the body.
 Radial and Anti-radial scan planes may also be used.
Radial and Anti-radial scan planes correlate with the
direction of the ductal system of the breast. Radial is
longitudinal or parallel with the ducts and anti-radial
is transverse or perpendicular to the ducts.
 Radial is the AIUM recommended scan plane for
breast imaging.
 Important note:
 If a solid lesion is found, the sonographer should scan
the lesion in the radial and anti-radial planes.
 This allows visualization of tumor or ductal extensions
branching toward or toward the nipple.
 These extensions could be missed in the sagittal and
transverse planes.
Annotation
 Labeling your images can be very time consuming, yet
very helpful for precise location of a lesion and followup studies. Most sonography departments use the
standard clock method for identifying the location of
lesions. This provides a more detailed description than
the quadrant method.
 SA may denote the subareolar region, and AX may
refer to the axillary region.
 In addition to the clock method, some Sonographers
also use the 123 and ABC methods of providing more
exact location.
123 Method
 The 123 method describes the location of a lesion in
comparison to its distance from the nipple.
 Location 1 is near the nipple.
 Location 2 is mid distance from the nipple.
 Location 3 is in the periphery of the breast.
123 Method
ABC Method
 The ABC method describes the depth of a lesion.
 Location A is superficial
 Location B is at mid depth (likely within the mammary
layer)
 Location C is near the chest wall.
Stand-off Pad
 A stand-off pad creates distance between the face of
the probe and the skin surface. Therefore, the fixed
elevation plane focus is moved more superficially.
 This allows improved focusing and greater detail in the
superficial layers of the breast.
 A stand-off pad improves imaging of:
 Superficial tumors of cysts
 Superficial vessels
 Superficial ducts
 Skin lesions
 Skin thickening
 Scanning surgical specimens
 Types of Stand-off Techniques include:
 Commercially produced gel pads
 Water bag
 Large “glob” of gel (used for imaging the nipple)
 Stand-off transducer attachments
 The ideal stand-off pad thickness for breast imaging is
1cm
 This places the elevation plane focus of a 10MHz
transducer at approximately 0.5cm depth within the
breast.
Normal Sonographic Appearance
 The echogenicity of breast tissue will vary with the amount
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and location of fat and fibrous tissue due to patient age,
functional state of the breasts, and body habitus.
For example, young women will tend to have more dense
fibroglandular tissue that appears HYPERECHOIC.
Older women tend to have more fatty replacement that
appears ISOECHOIC.
The lactating patient will have greater density appearing
HYPERECHOIC.
The obese patient will have more fat appearing
ISOECHOIC and the extremely thin patient will appear to
have more dense tissue appearing HYPERECHOIC.
 The breast is composed of three major tissue types
seen on sonography:
 Fat (superficial, intraparenchymal, and retromammary)
 Epithelium (TDLU and Acini)
 Stromal Tissue
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Loose stromal tissue (intralobular and periductal)
Dense stromal tissue (interlobular and Cooper’s ligaments.
Echogenicity
 Skin - HYPERECHOIC
 Thickness of 0.5 to 2mm. May see slight increase in
echogenicity at the gel/skin interface (sound beam entrance)
and the skin/superficial fat interface (exit).
 Fat – MEDIUM GRAY
 Found within the superficial layer, parenchymal layer, and
retromammary layer.
 All structures are compared to the mid-level echogenicity of
fat.
 Cooper’s Ligaments – HYPERECHOIC
 Considered part of the dense connective tissue. Best seen in
the subcutaneous fat layer as a thin, wavy linear structure.
May produce shadowing artifact- try changing the angle of
the transducer.
Sonographic Features of Benign
Disease
Shape and orientation
 Round
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Characteristic of tense cysts and small, solid, benign tumors
 Oval or Ellipsoid
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Typical of non-tense cysts and most benign tumors
 Horizontal orientation
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Also known as WIDER-THAN TALL, Length > AP, or Width >
Depth
Long axis of the tumor is parallel to chest wall
Benign tumors tend to grow within or along the tissue plane
(not crossing)
Margins
 Smooth, well-defined, or circumscribed
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Indicates the tumor is displacing adjacent tissues rather than
invading
 Macrolobulation
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Gentle, large lobulations
Border Thickness
 Thin, echogenic pseudocapsule
 Caused by compression or rimming of adjacent tissues
around the lesion (Opposite of Invasion)
Echogenicity
 Anechoic
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Simple cyst
 Hyperechoic
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Indicates a fibroglandular pseudomass or lipoma
 Mildly hypoechoic, isoechoic, or mildly hyperechoic
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Solid, benign tumors
Contradiction: some malignant tumors have same
echogenicity
 Homogeneous
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Internal echoes are a consistent, single shade of gray
Contradiction: some highly cellular malignant lesions may
appear homogeneous
Artifacts
 Acoustic Enhancement
 Caused by an increase in sound energy while passing through
tissue
 Most are cysts
 Solid, benign tumors may also display enhancement. This is
due to more uniform travel through the tumor than through
the surrounding tissue
 Enhancement artifact offers good visualization of the
posterior tumor wall.
 Contradiction: some highly cellular malignant tumors may
have A.E.
 Edge Shadowing
 Attenuation of the sound beam at the lateral margins of a
mass due to refraction.
Doppler
 Cysts have no internal flow
 Benign, solid masses demonstrate no flow or are hypovascular
(little Doppler signal)
Fibrous Planes
 Benign lesions tend to grow within or along fibrous planes,
compressing or displacing adjacent tissues
Ducts
 Ducts generally measure less than 3mm and increase in size
as they run toward the nipple
 Dilation or Duct Ectasia may occur due to a variety of normal
conditions: Lactation, 3rd trimester of pregnancy, and perimenopausal changes
 Duct dilatation may also be due to mastitis and fibrocystic
change or be seen with papillomas
 Contradiction: some duct dilatation may be associated with
ductal carcinoma or papillary carcinoma.
Margins
 Microlobulation
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Multiple small lobulations (usually 2mm)
 Ill-defined
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Obscured or indistinct margins that are poorly defined
Usually indicates tumor invasion into surrounding tissues
 Angular
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Irregular, jagged margins
Highly sensitive for malignancy
 Spiculated
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Straight lines which radiate from the center of a tumor
Radial Extensions
 Duct extension – extension of tumor into a duct
coursing toward the nipple
 Branch pattern – extension of tumor into a duct
coursing away from the nipple (usually involves multiple
ducts)
 Must be scanning in radial plane.