Endometrial sonography

Normal endometrium

Premenopausal Endometrium

• During menstruation---- a thin echogenic line, 1–4 mm in thickness

• In early proliferative phase of the menstrual cycle(after day 6) becomes thicker (5–7 mm) and more echogenic relative to the myometrium, (glands, blood vessels, and stroma)

• Late proliferative (periovulatory) phase

• a multilayered appearance.

• an echogenic basal layer and hypoechoic inner functional layer, separated by a thin echogenic median layer.

• may measure up to 11 mm in thickness.

• During the secretory phase, becomes even thicker (7–16 mm) and more echogenic .

• stromal edema and glands distended with mucus and glycogen.

• increased posterior acoustic enhancement.

• The endometrium typically reaches a maximum thickness during the mid secretory phase

On Ultrasound

• Endometrial thickness is measured from echogenic border to echogenic border across the endometrial cavity on a sagittal midline image.

Postmenopausal Endometrium

• should be thin, homogeneous, and echogenic.

• Homogeneous, smooth endometriameasuring 5 mm or less are considered within the normal range with or without hormonal replacement therapy.

Endometrial Polyps

• a common cause of postmenopausal bleeding

• most frequently seen in patients receiving tamoxifen or HRT.

• may be broad-based and sessile or pedunculated.

• Typically measure 5-15mm.

• The point of attachment should not disrupt the endometrial lining.

Ultrasonographic appearance

• frequently identified as focal masses within the endometrial canal.

• as nonspecific endometrial thickening.

• Color Doppler US may be used to image vessels within the stalk

Sonohysterogram reveals a small polyp attached by a stalk to the endometrium.

Endometrial polyp.

Multiple endometrial polyp.

• Endometrial fibroids are hypoechoic, well demonstrated in echogenic endometrium of secretory phase and have peripheral vascularity, typical of fibroids

Endometrial hyperplasia

• an abnormal proliferation of endometrial stroma and glands

• represents a spectrum of endometrial changes ranging from glandular atypia to frank neoplasia

Causes

• Polycystic ovaries

• Obesity

• Exogenous hormones

• Endogenous excess estrogen production

Ultrasonographic appearance

Endometrial hyperplasia is considered

• when the endometrium exceeds 10 mm in thickness, especially in menopausal patients

• In postmenopausal women 5mm thickness is significant.

Endometrial hyperplasia. US image shows an endometrium with diffuse thickening (maximum thickness, 1.74 cm) due to hyperplasia. This finding was confirmed at biopsy.

Endometritis

• Acute endometritis presents as thick, isoechoic endometrium with disruption of junctional zone

• minimal fluid in endometrial cavity and increased vascularity, even in early follicular phase.

Synechiae

• When the endometrium is triple line or the cavity is distended with the fluid, synechiae are seen as lines bridging between layers of endometrium

• Other endometrial lesions are postcurettageendometrial collection, vesicular mole, missed abortion, incomplete abortion, etc.

• These are all avascular and show heterogeneous echogenicity. Clinical history guides to the diagnosis

• Vesicular mole shows a thick echogenic endometrium with small anechoic areas snowstorm appearance.

• This echogenicity is higher than that of a normal secretory endometrium as it is because of decidual reaction.

• If it becomes malignant, it would break the endometriomyometrial interface