Understanding The Endometrium At Menopause: A Sonologist's View.

INTRODUCTION

Pathology of the endometrium is common, the presentation and management of the disease depends on a woman's age, her menstrual history, reproductive history, co-morbidities and use of medications. It is important to distinguish benign from malignant premalignant conditions.

The most common and first line used imaging modality for evaluating the endometrium is pelvic ultrasound with transvaginal and transabdominal

This pictorial review depicts the normal and abnormal appearance of the endometrium at post menopause

TIMING AND METHOD

Transvaginal is an ideal method. A transabdominal scan may be needed in cases of large fibroids, a globally enlarged uterus, virgins, amd is vaginismus or secondary vaginal stenosis. Transrectal -If transabdominal is inconclusive and is acceptable to the woman

In a postmenopoausal woman not on hormone therapy or on a continuous combined regime endometrium is assessed by a transvaginal scan, on any day when on cyclic combined regime 5–10 days after the last progestin pill[1].

TECHNIQUE

Start with the identification of the bladder and cervix

The position of the uterus is noted and measurements taken.

The uterus is scanned in the sagittal plane from cornu to cornu and in the (oblique) transverse plane from the cervix to the fundus.

In cases of difficulty to trace endometrium

Trace from the endocervical canal

The angle of insonation between the endometrium and the ultrasound beam should be 90° to optimize image quality , if possible

Enhanced sonography by instilling saline or gel

THE INTERNATIONAL ENDOMETRIAL TUMOR ANALYSIS (IETA)

The International Endometrial Tumor Analysis (IETA) group was formed in Chicago at the World Congress of Ultrasound in Obstetrics and Gynecology in 2008 with the aim of agreeing on terms and definitions to describe ultrasound findings in the uterine cavity. A consensus opinion from the International Endometrial Tumor Analysis (IETA) group was developed on the terms, definitions and measurements to describe the sonographic features of the endometrium and intrauterine lesions[2].

STUDY OF THE ENDOMETRIUM IN MENOPAUSE IETA GUIDELINES:

Quantitative:

Thickness of the endometrium-visible, interuppted, invisible

Qualitative:

Echogenicity

Uniform-homogeneous, hyperechogenic, isoechogenic or hypoechogenic

Non-uniform-homogeneous with regular or irregular cysts, heterogeneous with or without cysts.

Pattern-three-layer or monolayer pattern.

Endometrial midline-linear, non-linear, irregular or not defined

Bright edge-A bright edge is the echo formed by the interface between an intracavitary lesion and the endometrium.

Endo-myometrial junction-regular, irregular, interrupted or not visible.

Intracavity fluid.

Color-Doppler

The Color-Doppler score is a subjective assessment of the amount of color, reflecting the vascularity, and is scored as

a.1 (no color), b.2 (minimal color), c.3 (moderate color) d. 4(abundant color).

The vascular pattern may be a

single dominant vessel with or without branching

multiple vessels of focal or multifocal origin,

scattered flow

circular

Sonohysterography

In fluid-instillation sonography or enhanced ultrasonography, fluid is instilled into the uterine cavity transcervically to provide enhanced endometrial visualization during transvaginal ultrasound examination. The technique improves sonographic detection of endometrial pathology, such as polyps, hyperplasia, cancer, leiomyomas, and adhesions. Endometrial thickness of both endometrial layers.

In the presence of an intracavitary lesion, look for extent, type of localized lesion, echogenicity, outline, color score and vascular pattern.

ENDOMETRIUM-IMPLEMENTATION OF IETA

Quantitative Assesment

Endometrial thickness : how should it be measured?

The endometrium should be measured where it appears to be at its thickest.

When intracavitary fluid is present, the thickness of both single layers is measured in the sagittal plane and the sum is recorded.

If the endometrium is thickened asymmetrically, the anterior and posterior endometrial thicknesses should also be reported separately.

QUALITATIVE ASSESMENT

Endometrial echogenicity and pattern

Endometrial midline

“Bright edge“

Endo-myometrial junction

ENDOMETRIUM AT REPRODUCTIVE STAGE, AT MENOPAUSE AND POSTMENOPAUSE

Normally the menopausal endometrium is thin Sometimes it is difficult to see and measure as in upright position, vascular calcifications and calcified fibroids

POST MENOPAUSAL UTERUS

Smaller in size <7.5 cm

Uterine body to cervix 1;1

Calcified arcuate vessels – elderly post menopausal women

Median endometrial thickness 2.9-3mm

Not measurable /not visible 10 %

>5 mm 7-24%

<5 mm 76-93 %[3]

Do not measure the endometrium if you do not see it Plan a sonohysterography

APPROACH TO POSTMENOPAUSAL ENDOMETRIUM

Asymptomatic - Pathology discovered incidentally on scan

Symptomatic - Scan on indication

Aim:

To understand the cause of bleeding

To estimate risk of endometrial cancer

In women with cancer to asses the tumor invasion

To determine the optimal biopsy procedure

THICKENED ENDOMETRIUM DIFFERENTIAL DIAGNOSIS

Endometrial polyp

Submucus myoma

Hyperplasia endometrium

Endometrial carcinoma

Endometrial hyperplasia and endometrial carcinoma (EC) are histological diagnosis

how to recognize on sonography?

FOLLOW THE IETA RULES

WHAT ARE FOCAL LESIONS?

WHEN ENDOMETRIUM >5 mm

No focal lesions at SIS

Decreases the odds of pathology 30 times

Decreases the odds of cancer 20 times[4]

Irregular focal lesion is a strong sign of malignancy

FEATURES OF A BENIGN POLYP

Uniform hyperechogenic

Bright edge

Undefined midline echo

May or may not have cysts

Regular endomyometrial junctional zone

Single vessel without branching

Color score 2-3

POLYP WITH MALIGNANT CHANGE

48 years post menopausal spotting

Polyp large occupying the entire cavity

The 'bright edge' echo formed by the interface between an intracavitary lesion and the endometrium

Marked increase in vascularity with chaotic vascularity

MEASURING ENDOMETRIUM WITH AN INTRACAVITORY LESION

AN INTRACAVITARY MYOMA

Myoma should not be included in the measurement of endometrial thickness

IF INTRACAVITORY PATHOLOGY PRESENT

The total endometrial thickness including the lesion should be recorded.

FLUID IN THE CAVITY

Fluid in the cavity in post menopausal uterus always exclude malignancy particularly if associated with a focal irregular lesion[5]

UNDERSTANDING ENDOMETRIAL THICKNESS IN POSTMENOPAUSAL BLEEDING

Endometrial thickness

< 4 mm low risk cancer risk- Endometrial sampling if rebleed or at high risk for EC

> 5 mm High risk - Endometrial pathology 80%, Uterine malignancy 25%

Endometrium >4.5 mm saline sonography to determine focal or non focal

Normal looking polyp will have a malignant or premalignant potential of 6%

Unmeasurable not necessarily thin beware of cancer 5 % always perform hydrosonohysterography

The sensitivity for detecting EC at 3mm is 98%, at 4mm is 95%, and at 5 mm is 90%. However, using a low threshold is associated with a high false-positive rate.

In women with homogeneous and normal morphology, those on MHT, and hypertensive medication, the acceptable combined thickness is 6 mm

A focal increased echogenicity or a diffuse heterogeneity in the endometrium in a thin endometrium -Endometrial sampling[6]

UNDERSTANDING ENDOMETRIAL THICKNESS IN ASYMPTOMATIC WOMEN

In an asymptomatic early postmenopausal woman, an endometrial thickness of >11 should prompt an endometrial biopsy[7]

ENDOMETRIAL HYPERPLASIA

Thick endometrium

Hyperechogenic

Possibly cysts in the endometrium

Midline echo present

No feeding vessel

No polyp at hydrosonography

SIMPLE HYPERPLASIA WITHOUT ATYPIA

COMPLEX HYPERPLASIA WITH ATYPICAL HYPERPLASIA

Thickened endometrium with cystic spaces

Multiple vessels without origin

Intact endomyometrial junctional zone

Color score 2-3 Multifocal linear single vessels crossing EMJ

ENDOMETRIAL CANCER

Interrupted endo myometrial junctional zone

High color score > or equal to 3-4 - Malignant

Multiple and densely packed irregular branching vessels

ENDOMETRIAL CARCINOMA

Thickened endometrium with heterogenous echotexture

loss of endomyometrial junctional zone

Color score 3-4

Random dispersed not arising from EMJ

Myometrium normal

EC LIMITED TO ENDOMETRIUM IN AN ASYMPTOMATIC POSTMENOPAUSAL WOMAN

49 year old, asymptomatic, family h/o endometrial malignancy, detected during routine screening, endometrium 8 cm, volume 591cc, normal myometrium intact junctional zone marked increased vascularity

Histopathology

Endometrial intraepithelial neoplasia with atypia, few foci of endometroid adenocarcinoma

INVASION LESS LIKELY

Echogenity – hyperechogenity

Size – small tumor volume

Regular junctional zone

Thick tumor free myometrium

Low tumor perfusion score 1-2 single /no vessel

Histological grading low

LENDOMETRIAL CANCER IN POST MENOPAUSAL WOMAN WITH POSTMENOPAUSAL BLEEDING

Thickened endometrium 9.5 mm

Loss of endo myometrial junctional zone

Echogenecity – hypo or mixed echogencity

Size - larger tumor volume

High tumor perfusion– score 3 -4

Histological grading - high

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.