Breast Anatomy and Sonography PDF

The Breast Anatomy and Sonography Dalhousie School of Health Sciences DMUT 2050 – Topic 11 Anatomy of the Breast ⚫ Modified sweat glands ⚫ Main function A= ribs B= pectoralis minor  To secrete milk for lac...

The Breast Anatomy and Sonography Dalhousie School of Health Sciences DMUT 2050 – Topic 11 Anatomy of the Breast ⚫ Modified sweat glands ⚫ Main function A= ribs B= pectoralis minor  To secrete milk for lactation C= pectoralis major ⚫ Location  Anterior to the pectoralis muscle (major and minor) and ribs  Lateral to sternum  Medial to axilla Anatomy of the Breast ⚫Size of breast tissue is variable Age, functional state, amount of tissue of individual ⚫ in tissue with puberty and pregnancy Due to  in estrogen ⚫ in tissue (atrophy) after menopause Often fatty replacement Anatomy of the Breast ⚫Composed of 4-20 lobes of parenchymal tissue ⚫Interspersed with supporting tissue Fat (adipose) and fibrous connective tissue ⚫Lobes consist of: Lobules Ducts Small branch ducts Anatomy of the Breast Functional Unit ⚫Terminal DuctoLobular Unit (TDLU) A lobule ⚫Ductules ⚫Intralobular terminal duct ⚫Fibrous tissue (stroma) Extralobular terminal duct TDLUs are the site of origin of most breast pathologies and ANDIs Most breast carcinomas are thought to arise from the terminal duct near the junction of the Intralobular and Extralobular segments Anatomy of the Breast Ducts and Sinuses ⚫Smaller ducts unite to form larger ducts ⚫Eventually form lactiferous ducts May function as milk reservoirs ⚫Normal duct size fatty tissue More echogenic ⚫Breasts are more “dense” Causes issues with mammo Older women ⚫Fatty tissue > parenchymal tissue More hypoechoic ⚫Atrophy of mammary layer ⚫Other layers may appear more prominent Rumack Fig 20-10 Variable Appearances Rib 74 y.o. female, increased fatty tissue 24 y.o. female, increased glandular tissue The Breast Sonographic Appearance Hypoechoic duct Apposed walls ⚫ Ductal Variations Non-ectatic ducts ⚫ Purely anoechoic, hypoechoic or isoechoic or ⚫ Central, echo surrounded by isoechoic tissue Apposition of duct walls Ectatic ducts ⚫ Common, especially with increasing age ⚫ Anechoic or hypoechoic fluid separates duct walls Rumack Fig 20-11 Ectatic ducts Correlating US to a Mammogram ⚫We must ensure that the mammographic finding and the US finding are the same lesion ⚫The sonographer should have a basic understanding of mammography Mammography The Basics ⚫Radiographic procedure ⚫Non-invasive means of examining the breast However, uses ionizing radiation ⚫Gold-standard for breast screening exams ⚫Uses a compression paddle to compress breast between paddle and equipment Multiple positions and views are recorded Mammography - The Basics Standard Views ⚫Cranio-Caudal (CC) X-ray is directed from head (cranium) to feet (caudal) Cranio-Caudal (CC) View ⚫Determines whether a lesion is medial or lateral in the breast Markers indicate towards axilla “Lateral” Line perpendicular through nipple to chest wall Above line is lateral aspect Below line is medial aspect Mammography - The Basics Standard Views ⚫Medio-Lateral Oblique (MLO) X-ray is directed from medial (inner) to lateral (outer) aspects of breast Breast is at an oblique orientation Allows inclusion of axillary tail and muscle Medio-Lateral Oblique (MLO) View ⚫Determines whether a lesion is superior or inferior in the breast Line perpendicular through nipple to chest wall Above line is superior aspect Below line is inferior aspect Mammography-US Correlation Basic Lesion Location Lesion is above Lesion is line on CC view above line on in lateral aspect MLO view  in superior aspect Mammography-US Correlation Basic Lesion Location Lesion was found in RT Upper (Superior) Outer (Lateral) Quadrant (UOQ) on US Mammography Alternate Views ⚫90 Lateral 90 to Cranio-caudal No muscle or axillary tail is included  information is lost ⚫Spot Compression Focal compression on a suspected lesion (seen on mammo) BI-RADS Nomenclature – Table 21-1 ⚫ Breast Imaging - Reporting And Data System ⚫ Developed by the American College of Radiology To standardize reporting of breast lesions Clearly indicates management recommendations ⚫ Should be reported for every breast ultrasound ⚫ Uses same rules as mammographic reporting BI-RADS Nomenclature and Management Category Definition Examples Management BI-RADS 0 Incomplete assessment, needs Order another test (mammo, additional evaluation US or MRI) BI-RADS 1 Negative (Normal) Sonographically normal tissues Routine screening/follow-up 0% risk of malignancy that cause mammographic or clinical abnormalities BI-RADS 2 Benign findings Lymph nodes, simple cysts, Routine screening/follow-up 0% risk of malignancy ectatic ducts, definitively benign solid nodules (lipomas) BI-RADS 3 Probably benign findings Complex cysts, intraductal Surgical biopsy  2% risk of malignancy papillomas, some fibroadenomas Image guided biopsy Short interval US follow-up BI-RADS 4a Mildly suspicious findings Do not meet BIRADS 3 criteria Require biopsy >2-10% risk of malignancy May demonstrate some (Surgical or image-guided) malignant characteristics BI-RADS 4b Moderately suspicious findings >10-50% risk of malignancy BI-RADS 4c Moderately suspicious findings >50-94% risk of malignancy BI-RADS 5 Highly suggestive of malignancy Demonstrate multiple malignant Require biopsy ≥95% risk of malignancy characteristics (Surgical or image-guided) BI-RADS 6 Known biopsy-proven malignancy Patients pre-treatment Planning for chemo, radiation and/or surgery Breast Intervention Biopsy Cyst Aspiration Needle Localization Breast Intervention ⚫Breast Biopsy Large needle Solid lesions ⚫Breast Cyst Aspiration Thin needle Cystic lesions FNA Biopsy Breast Intervention ⚫Breast Lesion Localization Needle placed in lesion prior to biopsy or surgery Needle has “hook” to keep it in place Allows for precise localization of the lesion to be removed References ⚫ Demirkazik, F. B. (2008). Palpable and nonpalpable breast masses [Electronic version], Ultrasound Clinics, 3:3, 277-287. ⚫ Esen, G. & Olgun, D. C. (2008). Ultrasonography of the postsurgical breast including implants [Electronic version], Ultrasound Clinics, 3:3, 295-329. ⚫ Fahey, T. Digital mammography and breast ultrasound correlation [PDF document]. Retrieved from http://www.camrt.ca/english/pro_dev/AGC09-Presentations/Saturday/T_Fahey.pdf ⚫ Introduction to mammography (2004). Retrieved from http://www.e- radiography.net/technique/mammography/mammography_intro.htm ⚫ Mittelstaedt, C. A. (Ed.). (1992). General ultrasound. New York, NY: Churchill Livingstone Inc. ⚫ Rumack, C. M. & Levine, D. (Eds.). (2018). Diagnostic ultrasound (5th ed.). Philadelphia, PA: Elsevier Inc.