Figure 38.1 Illustrates normal zones of breast.

Echogenicity of structure from superficial to deep:

Hyperechoic—Skin (<2 millimeters thick)

Hypoechoic—Subcutaneous fat (Premammary s/c fat—Lobulated and more hyperechoic than fat elsewhere)

Hyperechoic—Fibroglandular parenchyma (12–20 ducts along with their lobules, fat, and stroma constitutes the breast parenchyma

Hypoechoic—Retromammary fat

Hyperechoic—Muscle (Pectoralis major)

Echogenicities of various structures:

Hyperechoic structures—Compact interlobular stromal fibrous tissue, anterior and posterior mammary fascia, Cooper’s ligament (thin echogenic bands), duct wall, and skin.

Isoechoic—Loose intralobular and periductal stromal fibrous tissue, fat, and epithelial tissues in ducts and lobules.

Hypoechoic—Retromammary fat.

Advantages and indications

1.    Ideal in young, pregnant, and lactating females (nonionizing)

2.    To differentiate cystic versus solid lesions

3.    In tender/inflamed breasts (no compression required as in mammography)

4.    To differentiate benign versus malignant lump

5.    Follow-up of cysts

6.    For lymph nodes

7.    As a guide for interventional procedures

8.    For implants

9.    For clinical breast mass with indeterminate mammogram

10.  Follow-up of cancer patients on chemotherapy

11.  Suspicious lump in males

Limitations

1.    Operator dependent.

2.    Low sensitivity especially for microcalcifications.

Technique—Scanning is done in supine and contralateral oblique position with arms comfortably under the head.