Basic Gynae Ultrasound

Roziana Ramli, OBGYN, HSNZ

Introduction

• USG: not a substitute for history, examination etc. LMP?

• Longer learning curve• Normal versus abnormal• TAS versus TVS, full bladder?• ‘Pelvic Organs’

NORMAL UTERUS;SHAPE AND SIZE

• Length - Fundus to Cervix(7.5-8.0cm)

• Depth - Antero-posterior(4.5-5.0cm)

• Width - Coronal view (2.5-3.0cm)

Menstrual Cycle

• Endometrial Development

– Cyclic changes during the menstrual cycle

– Endometrial thickness(ET): double wall thickness including both the anterior and posterior walls.

Menstrual Cycle

Appearance Thickness(mm)

Right after menses

Homogenous 1-4

Proliferative phase

Triple layer /Trilaminar

7-10

Luteal phase Hyperechogenic 8-16

NORMAL OVARY; SHAPE AND SIZE

The average size of the ovary in a premenopausal woman is 3.5 cm long by 2.0 cm wide by 1.0 cm thick

Ovary• Moderately echogenic• Found in POD to the lower abdomen• Anterior and lateral to the iliac vessels• Typically found lateral to uterine fundus• TAS: patient with thin adipose, TVS in

others

FOLLICLE AND CORPUS LUTEUM

• Developing follicles are first seen by ultrasound as group of 4-8 antral follicles 3-5mm on a TVS

• Around cycle days 9 to 10 the leading follicle can be identified; it has a diameter of about 10 mm. Thereafter it grows rapidly, and by ovulation it is 20 to 24 mm in diameter.

• The subordinate(non dominant) follicle reach 10mm then become atretic

• After ovulation the follicle collapses, and as the corpus luteum develops, the content of the cyst may have a slightly heterogeneous consistency. The wall thickens as cells are ‘luteinized’ (lining cells enlarge and fill with lipid) and in most cases the antrum fills with blood

• Occasionally, corpus luteum forms a homogeneous hypoechogenic thin-walled structure. The diameter of a normal follicle or corpus luteum does not usually exceed 30 mm.

– Fibroid– Adenomyosis– Patients with abnormal

bleeding

– Ovarian Cyst– Endometriosis– Teratomas– Ovarian Cancer

• Others

• Uterus • Ovary

Uterine fibroid

Ultrasound: fibroid

• Solid mass inside the body of the uterus– Well defined, ‘encapsulated’– Hyperechoeic OR hypoechoeic OR both

Fibroid: degenerative changesFibroids can undergo various degenerative changes, especially when large.

This fibroid shows multiple hypoechoic and hyperechoic patchy areas.

Sometimes degenerative changes can take place in fibroids with areas of necrosis and hemorrhage and result in varying appearances from cystic to inhomogenous appearances.

Fibroid: calcification

• Calcification of fibroids may occur as a peripheral ring or as popcorn type.

Adenomyosis

• Diagnosis with ultrasound is difficult as there are no characteristic features

• Diagnosed based on:– Myometrial echogenicity– Posterior uterine wall thickening– Anterior displacement of the endometrial cavity

Features suggestive of adenomyosis

– Uterine enlargement not explained by fibroid– Asymmetrical thickening of anterior or usually posterior uterine walls– Lack of contour or abnormality effect despite enlarged ‘bulky uterus’– Heterogenous and poorly circumscribed areas in the myometrium– Poorly defined focal area/s of hypo/hyperechoeic texture within the

myometrium– Anechoeic cysts or lacunae within the myometrium (myometrial

cysts)

A large (bulky) uterus with a diffusely infiltrative, inhomogenous appearance of the myometrium with dirty, streaky shadowing posteriorly.

The uterus shows a GLOBULAR shape with the endometrium almost obscured.

• Cystic areas within myometrium and endometrium. • The hyperechoic areas: caused by the migration of

endometrial tissue into the myometrium. • The hypoechoic areas: are the result of hyperplasia of

the myometrial smooth muscle around the ectopic endometrial tissue.

Bleeding Disorders

• Fertile Age• The most common causes

– Functional bleeding disorder of hormonal origin• Deviation from the normal structure of the

endometrium in the different phases of the menstrual cycle described above is not sufficient for making a diagnosis.

• Endometrial thickness of more than 18 mm suggests endometrial disease.

Bleeding disorders• Fertile Age• The most common causes

– Functional bleeding disorder of hormonal origin• Deviation from the normal structure of the endometrium in the different

phases of the menstrual cycle described above is not sufficient for making a diagnosis.

• Endometrial thickness of >18 mm suggests endometrial disease.

Postmenopausal Bleeding Disorders

• Postmenopausal bleeding is a sign of endometrial cancer until otherwise proven.

• An endometrial thickness >10 mm in a postmenopausal patient strongly suggests endometrial cancer and extremely rarely when the endometrium is < 5 mm thick.

• A histological sample of the endometrium is always needed these cases.

Endometrial polyp

An echodense, well-defined, round mass in the uterine cavity, which is best visualised during the proliferative phase. It may have a cystic structure.

The polyp can be imaged even better should any liquid be present in the uterine cavity, or if fluid is introduced with a catheter.

Ovarian Cyst

• Physiological versus pathological– Size < 5cm

• Benign versus malignant– 95% of cysts are benign

• Persistent of cyst >3 menstrual cycles

10 simple rules identifying benign & malignant ovarian tumour

Malignant (M) rules

• M1 Irregular solid tumor• M2 Presence of ascites• M3 At least 4 papillary structures• M4 Irregular multilocular solid tumor

with largest diameter ≥100 mm• M5 Very strong blood flow (color

score 4)

Benign (B) rules

• B1 Unilocular• B2 Presence of solid components

where the largest solid component has a largest diameter <7 mm

• B3 Presence of acoustic shadows• B4 Smooth multilocular tumor with

largest diameter <100 mm• B5 No blood flow (color score 1)

Pelvic Infection• Tubo-ovarian abscess is seen in US examination

as a multilocular, thick-walled mass that contains echo-dense fluid collections.

• When the infection subsides, the infectious complex may disappear or it may turn into a sactosalpinx, which is an elongated multilocular mass causing a torsion of the fallopian tube.

• The torsion is easily identifiable from different projections, and the ovary will be seen as a separate structure.

• Small pseudopapillae (1 to 2 mm) may be seen in the walls. Incomplete septa do not reach from wall to wall inside the mass.