Mammography

Chapter 23

2/21/2012

Radiographic studies of the breast

Breast Anatomy

Breast =mammary gland

Secondary sex characteristic

Consist of glandular, fat, and fibrous tissue

Base overlies pectoralis major muscles & serratus anterior

Part of breast extends into axillary fossa

(armpit)

Anatomy (cont’d)

Anatomy cont’d

• divided into 15 – 20 lobes

• each made up of lobules

• supported by Cooper’s ligament which determines firmness

Lobule size

• Affected by age and hormones (pregnancy)

• Involution: process of decreasing lobule size with age and after pregnancy

= flatter, saggier breasts

Anatomy (cont’d)

• Axillary nodes often evaluated on mammograms

• Because lymphatic vessels of breast drain into:

• Axillary lymph nodes, laterally

• Internal mammary lymph nodes, medially

Tissue Variations

Breasts consists of both glandular and connective

Ability to visualize depends upon amount of fat within and around breast lobules- provides contrast

Postpuberty breasts contain primarily dense connective tissue- harder to visualize

19 yr. old (never pregnant) 24 yr. old (has children)

Mammograms comparing 2 different women

Cancer that forms in tissues of breast – usually in ducts (tubes that carry milk to nipple)

and lobules (glands that make milk)

Can men get breast cancer?

Yes, but rare

Definition of breast cancer

Breast Cancer

Ranks Nationally as the 2nd leading cause of cancer-related deaths in women

What is first?lung cancer

Breast cancer in United States in 2009 (estimated):

New cases: 192,370 (female)

Deaths: 40,170 (female)

While breast cancer is less common at a young age (i.e., in their thirties)-

Younger women tend to have more aggressive breast cancers than older women, which may explain why survival rates are lower for young women

Breast Cancer Risk increases with:

Age

Hormonal history early menses late menopause pregnancy after age 30 or never had a child

Family historyIf daughter, mother, or sister has breast cancer

Pt.s in early stages respond well to treatment

Patients with advanced disease do poorly

Earlier diagnosis, better chance of survival

Mammography is the best way for early detection!

Mammography- Risk vs. Benefit

In 2007, in US –

133 deaths /million from breast cancer

5 deaths/million from mammography induced radiation (using screen film mammography)

Chances are 26 times more likely that a mammogram will save you rather than harm you!

More risky to refuse mammography!

What are your chances beating Breast Cancer ?

Excellent if diagnosed early!

If cancer is confined to breast, what is the survival rate for 5 years?

97%

Incidence of breast cancer stable since 1988

-but mortality rate decreased by 29%- mainly do to early detection

At what age should a woman have her first mammogram?

• In November 2009, the U.S. Preventive Services Task Force (USPSTF) changed their recommendations for routine mammography screening for woman aged 40-49:

• USPSTF now recommends against routine screening mammography in women aged 40 to 49 years!

• Decision to start regular, biennial screening mammography before age of 50 years should be an individual one and take into account family history and pt's values regarding specific benefits and harms

• 50-74 should have mammogram every other year

American College of Radiology and Society of Breast Imagingstrongly disagree!

Annual screening mammography should stay at age 40!

Mammography has reduced breast cancer death rate in United States by 30 percent since 1990

Based on data on performance of screening: mammography as currently practiced in US, one invasive cancer is found for every 556 mammograms performed in women in their 40s

Mammography only every other year in women 50-74 would miss 19 to 33 percent of cancers that could be detected by annual screening!

Did you get your annual mammogram?

In 2006: 56% of women of screening age (40 and up) reported having mammogram in past year

What race of women is most likely to have had a recent mammogram?

African American 68%

White 62%Latino/Hispanic 59%Asian American 55%

History of breast cancer detection

When was the first radical mastectomy introduced?1898

What year was the radiographic appearance of breast cancer first reported?

1913

When did mammography became a reliable diagnostic tool? in 1950s when industrial grade x-ray film introduced

History of breast cancer detection cont’d

1960’s Xerography introduced – excellent results and much lower dose than industrial film

1975 Low- dose mammography (High speed/resolution film) introduced by DuPont-

-(much lower dose- xerography discontinued)

Thermography

Thermography approved by United States FDA in 1983

Detects localized temperature elevations over cancers in the breast

In more than 90%, a "hot spot" will be evident if cancer is present

A complement to mammography only-

Can only spot superficial hot spots

MQSA (Mammography Quality Standards Act)

1992 – MQSA passed by Congress, enacted in 1994

Mammography became 1st and only federally regulated imaging exam, which mandated:

Formal training and continuing education

Required regular inspection of equipment

Documentation of quality assurance

Reporting results, follow-up, tracking pts, and monitoring outcomes

Types of Mammograms

Baseline mammogram: very 1st mammogram (or 1st mammo. after surgery)

Screening mammogram: all mammos after baseline- if pt. asymptomatic (no known breast problems)

Diagnostic Mammogram: when woman presents with clinical evidence of:

Breast disease

Palpable mass or other symptom

Typical Mammography Unit

Equipment is C-arm

SID is fixed at 24 – 26”

Mammography Equipment

Designed to produce high-contrast and high-resolution images

More precise control of kVp, mA, and exposure time

Low kVp : 25 – 28

AEC (automated exposure control)

Grid with ratio: 4:1, or 5:1 200 lines/inch

Screen-Film Systems

Mammography cassettes contain a single screen

Film is single emulsion

Occasionally, extended time processing is used(reduces dose and increases contrast)

Now largely replaced by digital imaging

Digital Mammography

State of the art!• No film or chemical processing• Much better definition• Compression needed about 5% less• Radiation dose about 22% less• Fewer repeats do to poor technique selection• Images easily sent over internet• Can give pt. CD of imagesPossible downside:

if 1st digital compared to previous film mammo., can give false positives due to increased sensitivity!

Procedure

Complete, careful history and physical assessment!

Take notes on location of scars, palpable masses, skin abnormalities, and nipple alterations

Examine previous mammograms for positioning, compression, and exposure factors

Procedure (con’t)

Have Pt put on gown with opening in front

Breasts must be bared for imagingCloth will cause image artifact

Remove deodorant and powder from axilla and breast

It can mimic calcifications on image!

Procedure (cont’d)

Explain procedure to pt., including possibility for additional projections

Consider natural mobility of breast before positioning

Support breast firmly so that nipple is directed forward in profile

Apply proper compression

Place ID markers

Compression

Decreases thickness of breast- thus reduces exposure dose

Decreases magnification and scatter

Increases contrast

Reduces motion unsharpness

Compression Device

Made of firm plastic

Amount of compression: between 25 and 40 pounds pressure

Compression may be….

uncomfortable!

Magnification

Increases visibility of small structures

Uses increase OID

Uses air gap

Why does Radiation dose increase with magnification even though technique is not increased?

-(breast is closer to source)

Digital Mammography now makes “mag films” obsolete

Routine mammography projections

Craniocaudal (CC)

Mediolateral oblique (MLO)

Craniocaudal Projection

Pt positionStanding or seated facing IR holder

Part positionElevate inframammary fold to maximum height

Adjust IR height to inferior surface of breast

Gently pull breast onto IR holder with both hands while instructing pt to press chest to IR holder

Craniocaudal Projection (cont’d)

Rotate head away from breast being examined (watch out for hair!)

Lean pt. toward machine

Move opposite breast out of the way

Place hand on shoulder and slide skin over clavicle

Compress breast slowly until skin taut

Criteria for adequate Craniocaudal Projection

Nipple should be in profile

maximum amount of breast tissue radiographed

CR – Perpendicular to base of breast

Structures shown – Central, subareolar, medial fibroglandular breast tissue, pectoral muscle

Mediolateral Oblique Projection Position

• Center breast with nipple in profile

• Hold breast up and out

• Compress breast slowly until taut

• Pull down on abdominal tissue to open inframammary fold

• Instruct pt. to hold opposite breast laterally, out of anatomy of interest

• Expose on suspended respiration

• Release compression immediately!

Criteria for acceptable Mediolateral Oblique projection

Deep and superficial breast tissues should be well separated

Retroglandular fat well seen

Uniform tissue exposure(adequate compression)

Other positions

Mediolateral Lateromedial

Breast Implants

Implants can be in front of pectoral muscle or behind

Saline vs Silicone

Silicone implants have a more natural look and feel – silicone gel texture similar to breast tissue

But Silicone implant ruptures are harder to detect

When silicone implants rupture, breast often looks and feels same because silicone gel may leak into surrounding areas of breast without visible difference

When saline implants rupture, they deflate -results are seen almost immediately

(MRI and sonography can help determine rupture or leakage)

Saline vs Silicone cont’d

Replacing a ruptured silicone gel implant is more difficult than repairing saline implant Silicone implants have higher rate of capsular contracture (scarring and hardening around implant)

Saline implants inflated to desired size with saline, then valve is sealed by surgeon

Radiography Of Augmented Breast (implants)

Complications:

Increased fibrous tissue surrounding implant (contracture)

Shrinkage Hardening Leakage Pain!

Radiography Of Augmented Breast (implants)

8 projections must be obtained (2x4) (twice as many as non-implants)

Four images of breast including anterior breast and implant

Four images with implant displaced posteriorly into chest wall are obtained

Eklund Technique for Radiographyof the Augmented Breast

What is Gynecomastia?

The development of abnormally large mammary glands in males- almost entirely fat

Can sometimes cause secretion of milk

Male Mammography

Approximately 1000 males develop breast cancer every year

Standard CC and MLO are obtained

Males not screened- mammogram only if lump discovered

Treatment For Breast Cancer

Lumpectomy

Partial or radical mastectomy

Radiation

Chemotherapy

(recent study shows that lumpectomy or mastectomy may be no more beneficial than radiation and chemotherapy)

Lesion

Needle Localizations

Used to localize breast lesions before surgery

Special, open-hole plate may be used for ease of localization

Lumpectomy-Breast Specimen Radiography

Imaging of lump by itself after it has been surgically excised

Breast Calcifications

Calcified Milk DuctsCalcified Milk Ducts

Benign Cyst