Breast anatomy and scan technique Flashcards
How many lobes are in the breast?
15-20
What are the three layers of breast tissue and their divisions?
Subcutaneous zone (between skin and anterior mammary fascia), mammary zone (between anterior and posterior mammary fascia), and retromammary zone (contains mostly fat, blood vessels, and lymphatics).
What breast layer is most likely affected by pathology?
Middle mammary zone
What are the different levels of axillary LN’s and what are their boundaries?
Level 1 - lateral and inferior to pec minor
Level 2 - deep to pec minor
Level 3 - superior and medial to pec minor
What are Rotter’s LN’s?
LN’s that lie between pec minor and pec major (interpectoral space).
Which LN’s of the breast area are most likely to be affected by pathology first?
Axillary LN’s (level 1).
Where are the internal mammary LN’s located?
Just lateral to the sternum
What other LN’s should be checked to see if invasion is extensive?
Supraclavicular and jugular LN’s.
What are Cooper’s ligaments?
Fibrous connections which run between the undersurface of the breast skin and the pectoral muscles.
What is the sentinel node?
The first LN that lymph and thus cancer drains into.
What are the four criteria of breast annotations to include upon discovery of a mass?
Side
Clock face position
Distance from nipple in cm
Transducer orientation
What is radial and antiradial scanning?
Scanning around the nipple in a clock fashion. Antiradial scanning is perpendicular to the line of this type of scanning.
What is the advantage of radial scanning?
Ducts lie radially in comparison to nipple so components of DCIS will be seen better.
What are some techniques that can be used to differentiate between a solid vs cystic breast mass?
Colour Doppler and ballotment (differentiates solid mass from cystic mass with internal echoes)
How can spatial compounding be utilised in breast imaging?
Turning it off can highlight posterior acoustic enhancement
Turning it on will mean the internal contents of the mass is less affected by artifact
What pathologies are associated with pain on ballotment?
Acutely inflamed cysts and acute periductal mastitis
How can Doppler be used to differentiate between benign reactive vs. metastatic LN’s?
Mets have transcapsular vascularity and high resistance waveform
What are the different types of benign cystic structures/features in the breast?
Simple
MOC cysts
Fat fluid level
Eggshell calcs (most often seen on mammo and don’t require US)
Clustered macrocysts
Cysts of skin origin
Foam and acorn cysts
What is the functional unit of the breast called and what is it comprised of?
Terminal duct lobular unit
Ductule drains into the interlobular terminal duct then into the extralobular terminal duct - these make up the TDLU
What should you have on the deepest portion of your screen when scanning the breast?
Pectoralis muscle
What technique can you use to prevent shadowing from Cooper’s ligaments?
Heel-toeing the transducer
What are the different descriptors we can use/assess when analysing breast lesions?
Margins (well-circumscribed, indistinct, angular, micro-lobulated, spiculated; is there a capsule - is it hyper/hypoechoic, is it thin or thick?)
Echogenicity
Posterior acoustic features
Surrounding tissue (any invasion into the ducts, changes to Cooper’s ligaments, architectural distortion, retraction. oedema?)
Vascularity (within, feeding vessel, surrounding the lesion?)
