Uterus normal

Uterus anatomy.

REF: Created by macrovector – www.freepik.com

Trans abdominal (TA) ultrasound

Uterus trans abdominal (TA) approach probe positioning for longitudinal scan.

The heel of the probe should be at symphysis pubis.

Angle the probe slightly towards the heard to have the ultrasound beam perpendicular to the uterus.

Ultrasound of Uterus sagittal, transabdominal approach, ultrasound image image.

Uterus transabdominal approach (TA) probe positioning for transverse scan.

Trans abdominal ultrasound view of the uterus: transverse. Both ovaries are visible (not always the case).

Trans vaginal (TV) ultrasound

Normal TV Ultrasound image anteverted sagittal.

The overall uterine length is evaluated in the long axis from the fundus to the cervix (external os). The depth (AP diameter) is measured from the anterior to the posterior wall and perpendicular to the length.

Transvaginal Technique Anteverted uterus.

Retroverted uterus transvaginal ultrasound scan.

Retroverted transvaginal technique hl.

Transverse TV ultrasound of the uterus.

The ultrasound probe is slowly rotated anticlockwise to visualise the uterus at 90degrees to the sagittal view. The Maximum Width is measured in this transverse (semi-coronal) plane.

Endometrial phases and measurement

Assess the endometrial status / phase.

Measure the combined thickness.

Schematic diagram showing the phases of the endometrium alongside the ovarian cycle.

Post menstrual the endometrium should be thin. the basal layer abuts the endometrial cavity showing a single echogenic layer.

Mid cycle, the endometrium has a ‘triple stripe’ appearance. Hyperechoic basal layer and endometrial cavity with a hypoechoic functional layer surrounding the cavity. By mid cycle a dominant follicle will normally be visualised on one ovary.

As the cycle progresses, the endometrium becomes more densely filled (hyperechoic). The dominant follicle may become complicated.

Post menstrual endometrium

Sagittal Ultrasound image of the uterus obtained during the early proliferative phase of the menstrual cycle demonstrates the endometrium beginning to take on a multilayered appearance.

Proliferative phase of the endometrium

The endometrium thickens following ovulation.

Secretory phase of the endometrium

Secretory phase

Sagittal ultrasound image of the uterus obtained during the secretory phase of the menstrual cycle shows a thickened, echogenic endometrium

Post Menopausal Uterus

Sagittal normal image of a post menopausal uterus.

Note the thin, atrophic endometrium.

Sagittal normal image of a post menopausal uterus. Note the AP diameter of the fundus to the cervix.

Paediatric Pelvis

The prepubertal uterus has a tubular configuration (anteroposterior cervix equal to anteroposterior fundus) or sometimes a spade shape (anteroposterior cervix larger than anteroposterior fundus). The endometrium is normally not apparent. The length is 2.5–4 cm;

The pubertal uterus has the adult pear configuration (fundus larger than cervix) (fundus-to-cervix ratio = 2/1 to 3/1) and is 5–8 cm long, 3 cm wide, and 1.5 cm thick.

 

The neonatal uterus may be prominent because it is under the influence of maternal and placental hormones. The cervix is larger than the fundus (fundus-to-cervix ratio = 1/2), the uterine length is approximately 3.5 cm, and the maximum thickness is approximately 1.4 cm; the endometrial lining is often echogenic.

 

 

Deslandes, A., Pannucio, C., Parasivam, S., Balogh, M., & Short, A. (2020). How to perform a gynaecological ultrasound in the paediatric or adolescent patient. Australasian journal of ultrasound in medicine, 23(1), 10-21. doi:10.1002/ajum.12200

IUCD (Intrauterine Contraceptive Device)

Copper IUD

The copper IUD is a small plastic device with copper wire wrapped around it and a fine nylon string attached to the end. When the IUD is in place, the string comes out through the cervix into the top of the vagina.

Hormonal IUD

The hormonal (Mirena) IUD is a small plastic ‘T-shaped’ device that contains progestogen. This is a synthetic version of the natural hormone progesterone. The device has a coating (membrane) that controls the release of the progestogen into the uterus. Like the copper IUD, it has a fine nylon string attached to the end to make checking and removing it easier. The hormonal IUD is available in Australia under the brand name Mirena.

Ultrasound is routinely used to check the position .

Ultrasound image of – IUCD is seen here approximately 1.5cm from the end of the uterine fundus.

Ultrasound of -The string is seen correctly positioned in the cervical canal.

“C” Plane

The coronal plane can improve visualisation of the uterine shape and the endometrium. Congenital abnormalities can be diagnosed more confidently. Fibroids and polyps are much easier to visualise. Cornual ectopics can also be better appreciated.

It is displayed by gaining a good 2D image and rendering it into 3D images.

This is a rendered 3D ultrasound  image using a Transvaginal approach.

Coronal 3D Ultrasound image of a Mirena IUD shows the expected location of the shaft and crossbars simultaneously in the body and fundus of the uterus. The endometrium is also seen well without the normal shadowing of the mirena always seen in the sagittal plane.

The string can be difficult to identify on the 3D ultrasound in the cervix but a 2D  sagittal ultrasound scan should easily show its placement.

SCAN PROTOCOL

Role of Ultrasound

  • To examine the uterus, ovaries, cervix, vagina and adnexae.
  • Classification of a mass identified on other modalities eg solid, cystic, mixed.
  • Post surgical complications eg abscess, oedema.
  • Guidance of injections, aspiration or biopsy.
  • Assistance with IVF.
  • To identify the relationship of normal anatomy and pathology to each other.

Indications

  • P/V bleeding/discharge
  • Menorrhagia
  • Metrorrhagia (irregular uterine bleeding)
  • Polymenorrhea
  • Menometrorrhagia (excessive irregular bleeding)
  • Amenorrhea
  • Oligomenorrhea
  • Pelvic pain
  • Dysmenorrhea (Painful Menses)
  • F/H uterine or ovarian Cancer
  • Palpable lump
  • Infertility- primary or secondary (evaluation,monitoring and/or treatment)
  • Anomalies/evaluation
  • Follow-up of previous abnormality
  • Precocious Puberty,delayed menses or vaginal bleeding in a prepubertal child.
  • postmenopausal bleeding
  • Signs/symptoms of pelvic infection
  • IUCD Localisation (intrauterine contraceptive Device)
  • Guidance for interventional or surgical procedures
  • urinary incontinence or pelvic organ prolapse

Limitations

  • Transvaginal scanning is contra-indicated if the patient is not yet sexually active or cannot provide informed consent.
  • Large patient habitus will reduce detail, particularly via the transabdominal approach.
  • Excessive bowel gas can obscure the ovaries.
  • Patients who are unsuitable for transvaginal scanning but canot adequately fill their bladder for an acoustic transabdominal window.

Patient Preparation

    • If possible, scan the patient in the first 10 days of the cycle. Preferably Day 5-10 for improved diagnostic accuracy in the assessment of the endometrium and ovaries.
    • A full bladder is required . Instruct the patient to drink 1 Litre of water to be finished 1 hour before and they cannot empty their bladder before the scan.
    • For paediatric patients depending on the age, 250-500 mls should be adequate. Please note that overfilling the bladder will change the shape of the uterus which is particularly relevant when assessing the paediatric uterus.
    • The patient empties their bladder before starting the transvaginal scan. 

Equipment setup

  • Transabdominal approach initially. Use the highest frequency probe to gain adequate penetration. This will be between a 2-7MHz range curved linear array or sector probe with Colour Doppler capabilities.
  • Transvaginal probe 4-7MHz.
  • A curved linear array probe can be used via the perineum to assess the vagina.Cover the probe.
  • For paediatric patients a linear curve often gives enough penetration for the pelvis. As patients get older a combination of linear and curved array should be utilised keeping in mind the ALARA principle.

Common Pathology

VAGINAL

  • Gartners duct cyst
  • Vaginal carcinoma
  • Hydro/haematocolpos (secondary to imperforate hymen or vaginal stenosis)
  • Foreign body

CERVICAL

  • Nabothian (retention) cysts
  • Polyps
  • Cervical fibroids
  • Cervical carcinoma
  • Cervical stenosis

UTERINE

  • Fibroids (leiomyoma)
    • submucosal
    • intramural
    • subserosal
    • pedunculated
  • Leiomyosarcoma
  • Adenomyosis
  • Lipoleiomyoma

ENDOMETRIAL

  • Endometrial Polyps
  • Endometrial Carcinoma
  • Endomtrial hyperplasia
  • Endometritis
  • Cystic hyperplasia secondary to Tamoxifen
  • Adhesions- Ashermans Syndrome
  • Submucosal fibroids
  • Arterio-venous malformation (AVM)
  • Hydro/haematometra
  • Blood/fluid/infection or retained products of conception (RPOC)

OVARIAN

  • Ovarian cysts
    • simple Vs complex (haemorrhagic, corpus luteal, ruptured, septated).
    • any mural nodules
  • Dermoid
  • Ovarian tumours:
    • Cystadenoma (serous/mucinous)-Benign
    • Cystadenocarcinoma (serous/mucinous)-Malignant
  • Polycystic Ovarian Disease
  • Endometrioma
  • Torsion
  • Hyperstimulation syndrome
  • Ectopic pregnancy

POUCH OF DOUGLAS (POD) & ADNEXAE

  • Fluid
  • Pus
  • Blood
  • Pelvic inflammatory disease-PID (may be indicated by above conditions)
  • Cysts (Mesenteric)
  • Ectopic pregnancy
  • Endometriosis
  • Pelvic venous congestion
  • Bowel pathology may be seen (but cannot be excluded)

FALLOPIAN TUBES

  • PID
  • Pyosalpynx
  • Hydrosalpynx
  • Ectopic pregnancy
  • Cyst
  • Endometriosis

Bladder and Bowel should also be examined.

SCANNING TECHNIQUE

TRANS-ABDOMINAL APPROACH

This is a generalised overview to identify the cervix, uterus and ovaries.

  1. Check for the orientation the uterus (anteverted V’s retroverted)
  2. Assess the uterine size and shape.
  3. Assess the myometrium
  4. Assess the endometrial status and measure the thickness: <10mm pre menopausal; <4mm post menopause or ,<6mm if post menopausal on HRT
  5. Assess the cervix
  6. Look for free fluid in the pouch of douglas
  7. Check the ovaries and adnexae
  8. Assess bladder

Scan sagitally in the midline immediately above the pubis. Heel the probe to get the bladder over the fundus of the uterus. In this plane you should be able to assess the uterus, vagina and cervix. Zoom the image to assess and measure the endometrial thickness. Rotate into transverse and angle slightly cranially to be perpendicular to the uterus.  Whilst in transverse and slightly right of midline, angle left laterally to identify the left ovary using the full bladder as an acoustic window. Examine the ovary in two planes. Now repeat this for the right ovary.

TRANS-VAGINAL(TV) APPROACH 

INSERTING THE TV PROBE

  • Before letting the patient empty their bladder, show them the TV probe and explain the procedure. Indicate the length that is inserted which is approximately the length of a standard tampon. Explain there is no speculum used. Explain the importance of a TV scan because it is the gold standard in gynaecological ultrasound because of its superior accuracy and improved diagnostic resolution.
  • Cover the probe with a latex free TV sheath and lubricate with sterile gel on the outside.
  • Elevate the patients bottom on a thick sponge/pillow to assist the scan. A gynae ultrasound couch which drops down is ideal so that a better angulation is achieved for an anteverted uterus.
  • Ensure the patient is ready and get permission before inserting the probe.
  • If there is some resistance as the probe is being inserted, offer for the patient to help guide the probe in far enough to see the end of the fundus.
  • Keep asking the patient if they are okay.
  • When manouvering the probe to visualise the adnexae, withdraw slightly then angle the probe towards the fornix. This avoids unnecessary patient discomfort against the cervix.

CONSENT FOR TRANSVAGINAL ULTRASOUND

  • https://www.asum.com.au/files/public/SoP/curver/Obs-Gynae/Policy-on-Vaginal-Scanning-by-Sonographers.pdf

DISINFECTION

Departmental and National Policies should be adhered to.

Guidelines for Reprocessing Ultrasound Transducers. (2017). Australasian journal of ultrasound in medicine, 20(1), 30-40. doi:10.1002/ajum.12042

Basic Hardcopy Imaging

A pelvic series should include the following minimum images;

  • Uterus – longitudinal, transverse (with measurements)
  • Endometrial thickness measured in the longitudinal plane
  • 3D coronal view of the uterus
  • Cervix
  • Both ovaries- longitudinal, transverse
  • Both adnexae
  • Document the normal anatomy. Any pathology found in 2 planes, including measurements and any vascularity.