Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Gynaecology


Imaging Techniques in Gynaecology

Ultrasound (US)

Indications

Evaluation of a pelvic mass, uterine enlargement, endometrial abnormalities, ovarian masses or acute pelvic pain ▸ it allows transabdominal and transvaginal guidance of fluid or tissue sampling ▸ it allows transvaginal-guided drain placement and guidance for placement of brachytherapy for cervical and endometrial malignancy ▸ it allows intraoperative assessment for the completion of evacuation of products of conception

  • Transabdominal US (TAS): a full bladder is required ▸ a 3.5–5 MHz transducer is used

  • Transvaginal US (TVS): an empty bladder is required ▸ a 5–8 MHz transducer is used ▸ it allows closer apposition to the pelvic organs

  • Doppler US: this provides information on vascularity

Normal US anatomy

  • Premenopausal

    • ▪

      Uterus: 5–9 cm in length

    • ▪

      Endometrium: proliferative phase: ≤8 mm ▸ midcycle: a trilaminar appearance measuring up to 12–16 mm ▸ secretory phase: hyperechoic due to the increasing glandular complexity ▸ ≤16 mm

    • ▪

      Ovaries: these are anterior to the iliac vessels ▸ they typically measure 30 mm in any two dimensions but may measure ≥50 mm in one plane ▸ the ovarian volume is usually <10 cm 3

  • Postmenopausal

    • ▪

      Endometrium: <5 mm (unless on hormonal therapy, when it can measure ≤8 mm)

Computed tomography (CT)

Indications

The distant staging of gynaecological malignancies ▸ the detection of persistent and recurrent pelvic tumour ▸ for biopsy guidance

Normal CT anatomy

  • Uterus: a triangular or ovoid soft tissue structure located behind the urinary bladder ▸ the myometrium enhances with contrast (helping to delineate the endometrium, which is of lower attenuation)

  • Cervix: a rounded structure inferior to the uterine corpus

  • Vagina: a flat rectangular structure at the level of the fornix

  • Broad and round ligaments: these are seen coursing laterally and anteriorly (respectively)

  • Ovaries: these are posterolateral to the uterine corpus ▸ they are of soft tissue density with small cystic regions ▸ they are atrophic in postmenopausal women

Magnetic resonance imaging (MRI)

Indications

For the evaluation of Müllerian duct anomalies ▸ for the local staging of uterine and cervical cancer ▸ as a problem-solving tool in the evaluation of adnexal masses ▸ allowing differentiation between radiation fibrosis and recurrent tumour ▸ permitting radiologically guided biopsies

Normal MRI anatomy

T1WI

The pelvic musculature and viscera are of homogeneous low-to-intermediate SI

T1 + Gad

  • The endometrium and outer myometrium enhances more than the junctional zone

  • The inner cervical mucosa and outer smooth muscle enhances more than the fibrocervical stroma

T2WI

The zonal anatomy is demonstrated as follows:

  • Uterus:

    • ▪

      Endometrium: this is of high SI ▸ ≤8 mm (proliferative phase) ▸ ≤16 mm (secretory phase) ▸ <5 mm (postmenopausal women that are not receiving hormonal therapy)

    • ▪

      Junctional zone (representing the innermost myometrium): this is of low SI (due to its low water content)

    • ▪

      Peripheral myometrium: this is of intermediate SI (and higher than striated muscle)

  • Cervix:

    • ▪

      Endocervical glands and mucus: central high SI

    • ▪

      Stroma: low SI (as it is composed of elastic fibrous tissue)

    • ▪

      Periphery of cervix: intermediate SI similar to myometrium (as it is composed of smooth muscle)

  • Vagina:

    • ▪

      Mucosa: high SI

    • ▪

      Vaginal wall: intermediate SI

  • Ovaries: The follicles demonstrate higher SI than the surrounding stroma

Other imaging techniques

FDG-PET and FDG-PET/CT

This uses a glucose analogue, 2-[ 18 F]-fluoro-2-deoxy-D-glucose (FDG) ▸ it is not widely available but can be used in cervical and ovarian cancer

Hysterosalpingography (HSG)

Radiopaque contrast medium is instilled into the uterus and Fallopian tubes ▸ it is used for the evaluation of infertility

  • Cervical canal: 3–4 cm long and the length of the uterus (it shortens after childbirth) ▸ it is often spindle shaped and there may be glandular filling

  • Cavity of uterine body: this is triangular in shape ▸ the average length and intercornual diameter is approximately 35 mm

  • Fallopian tubes: these are 5–6 cm long ▸ the isthmus is of uniform diameter and opens laterally into a wide ampulla

Sonohysterography

A 5F catheter is placed through the cervix ▸ distension of the uterine cavity is obtained with sterile saline under direct US visualization

  • This is more accurate than endovaginal US alone ▸ focal pathology can be differentiated from diffuse endometrial conditions with increased accuracy ▸ it can differentiate between intracavitary, endometrial and subendometrial pathology ▸ it can evaluate tubal patency

(A) Transvaginal US shows normal endometrium (arrows) in proliferative phase and (B) in follicular phase (arrows). (C) Sagittal transvaginal US shows a normal ovary (O) with follicles. Note the location of the ovary anterior and medial to the internal iliac vessels (I) within the ovarian fossa. *

Zonal anatomy of the uterus. Sagittal T2WI. The central, high SI stripe represents the endometrium (small arrows) ▸ the band of low SI subjacent to the endometrial stripe represents the inner myometrium or junctional zone (arrows). The outer layer of the myometrium is of intermediate SI (open arrow). bl = bladder. *

CT. (A) Normal uterus with a low attenuation endometrial canal (*) flanked by enhancing myometrium (arrowheads). Enhancing endocervical mucosa (short solid white arrows) surrounds the endocervical canal. The fibrous cervical stroma (open black arrows) enhances less than the uterine corpus myometrium. (B) Bilateral physiological ovarian cysts (*) in their expected location (anterior to the internal iliac vessels and posterior to the external iliac vessels). *

Normal hysterosalpingogram. Cervix and uterine body are delineated by contrast media. Both Fallopian tubes are shown (arrows), with early peritoneal spill. *

Sonohysterography. Sagittal transvaginal US (A) demonstrates the inflated balloon of the sonohysterographic catheter (*) within the endometrial canal. Following the instillation of 40 ml of sterile saline (B), fluid distends the endometrial canal. *

Congenital Anomalies of the Female Genital Tract

Congenital Anomalies of the Female Genital Tract

Definition

  • Embryology: the uterus, upper of the vagina and Fallopian tubes are derived from the paired Müllerian ducts ▸ at approximately 10 weeks following conception the ducts migrate caudally and undergo fusion and subsequent canalization ▸ congenital anomalies arise when this process is interrupted:

    • ▪

      Non-development: uterine agenesis

    • ▪

      Varying degrees of non-fusion: a didelphys or bicornuate uterus

    • ▪

      Non-resorption of the Müllerian ducts: septate uterus

Clinical presentation

Asymptomatic ▸ menstrual disorders ▸ infertility ▸ obstetric complications

  • Congenital anomalies are present in 1–15% of women, with associated renal anomalies in up to 50% of cases

Radiological features (MRI)

Uterine anomalies

Class I: Müllerian (uterine) agenesis or hypoplasia

  • Due to non-development or rudimentary development of the Müllerian ducts

    • ▪

      Uterine hypoplasia: a small uterus with an atrophic endometrium ▸ T2WI: the myometrium is of lower SI than normal ▸ ovaries are normal

    • ▪

      Uterine agenesis: MRKH Syndrome

Class II: unicornuate uterus

  • Due to non-development or rudimentary development of one Müllerian duct ▸ the remaining Müllerian duct is fully developed ▸ increased obstetric complications/renal abnormalities

  • T2WI: a ‘banana-like configuration’ of the normal duct: there is a curved, elongated uterus with tapering of the fundal segment off the midline ▸ the normal uterine zonal anatomy is maintained ▸ the rudimentary horn demonstrates lower SI

Class III: uterus didelphys

  • Due to non-fusion of the two Müllerian ducts

  • T2WI: there are two widely separate normally sized uterine horns with two cervices ▸ the endometrial and myometrial widths are preserved ▸ vaginal septum (75%)

  • T1WI: haemorrhage may be seen if there is a transverse septa causing obstruction

Class IV: bicornuate uterus

  • Due to partial fusion of the Müllerian ducts (with incomplete fusion of the cephalad extent of the uterovaginal horns with resorption of the uterovaginal septum) ▸ obstetric complications relate to the degree of horn fusion

  • The uterine horns are separated by an intervening cleft (>1 cm) within the external fundal myometrium ▸ a normal zonal anatomy is seen within each horn + a dividing septum composed of central myometrium

    • ▪

      Bicornuate unicollis: the central myometrium extends to the internal os

    • ▪

      Bicornuate bicollis: the central myometrium extends to the external os ▸ there is some fusion between the two horns (cf. complete separation with didelphys)

Class V: septate uterus

    • ▪

      Due to incomplete resorption of the final fibrous septum between the two uterine horns

    • ▪

      The septum may be partial, or it may be complete and extend to the external cervical os

  • T2WI (parallel to uterine long axis): a convex, flat or concave (<1 cm) external uterine contour (+ fibrous septa)

Class VI: arcuate uterus

  • Single uterine cavity with a convex / flat uterine fundus

  • Uterine cavity demonstrates a small fundal cleft ▸ often considered a normal variant ▸ no effect on pregnancy

Class VII: in utero diethylstilbestrol (DES) exposure

  • Uterine hypoplasia with a ‘T-shaped’ uterus

Vaginal anomalies

Congenital absence of Müllerian ducts (vaginal aplasia, MRKH syndrome)

  • Due to failure of the vaginal plate to form, or a failure of cavitation

  • MRKH syndrome: upper vaginal agenesis or hypoplasia (with normal ovaries and Fallopian tubes) accompanied by variable anomalies of uterus (class 1), urinary tract and skeletal system

Disorder of vertical fusion

  • A transverse vaginal septum prevents loss of menstrual blood and results in haematocolpos

  • T2WI: a dilated vagina with intraluminal fluid of intermediate or high SI (± fluid and debris levels) ▸ the lower of the vagina is replaced by low SI fibrous tissue with loss of the normal zonal anatomy

  • T1WI (+ fat suppression): this confirms the presence of any blood products which appear of high SI

Disorder of lateral fusion

  • This often presents with an incidental asymptomatic vaginal septum

Vaginal cysts

  • Gartner duct cysts: anterolateral upper vagina above pubic symphysis

  • Bartholin gland cysts: posterolateral lateral vaginal introitus below pubic symphysis

  • Nabothian cysts: cervical cysts

Pearls

  • Compared to a bicornuate uterus, a septate uterus is associated with a higher rate of reproductive complications

    • ▪

      A collagenous septum cannot support a pregnancy as well as a myometrial septum

  • A transverse vaginal septum in adolescence with cyclical abdominal pain + a pelvic mass

Congenital abnormalities of the uterus.

Vaginal septum. Sagittal T2WI shows the presence of haematometra (*) caused by a transverse vaginal septum. *

Uterus bicornuate. Coronal T2WI demonstrating two endometrial canals (*). *

Absence of the uterus. Sagittal T2WI shows no uterine tissue. *

Uterine and vaginal agenesis. Sagittal T2-weighted MRI of the pelvis showing absent uterus and vagina. **

Uterus didelphys. T2-weighted axial oblique MRI elegantly demonstrates two separate normal-sized uterine horns and cervices. **

Benign Uterine Conditions

Leiomyoma (Fibroid)

Definition

  • A benign tumour arising from uterine smooth muscle cells (± varying amounts of fibrous tissue) ▸ it is oestrogen dependent, and therefore regresses after the menopause

  • It is the most common uterine tumour (seen in up to 40% of premenopausal women) ▸ they are usually multiple

    • ▪

      Intramural: the most common type

    • ▪

      Submucosal: this is the most likely to be symptomatic

    • ▪

      Subserosal: this may be pedunculated (± torsion)

Clinical Presentation

  • Menorrhagia (if there is a submucosal location) ▸ dysmenorrhoea ▸ subfertility (due to narrowed Fallopian tube or interference with implantation) ▸ urinary frequency

    • ▪

      Red degeneration: this follows acute impairment of the blood supply (often during pregnancy), and presents with acute abdominal pain and tenderness

    • ▪

      Hyaline degeneration: there is gradual impairment of the blood supply, and it is asymptomatic

    • ▪

      Obstetric complications: malposition ▸ a retained placenta ▸ interference with vaginal delivery ▸ premature uterine contractions

  • Fibroids are more prevalent amongst black women

Radiological Features

US

An enlarged uterus (± an irregular and lobular outline) ▸ a well-marginated, hypoechoic, rounded mass within the uterine body ▸ distortion of the endometrial complex if there is a submucosal component

  • Depending on the proportion of smooth muscle, fibrosis and degeneration, appearances can range from hypoechoic to echogenic, and homogeneous to heterogeneous ▸ there can be acoustic shadowing or shadowing echogenic foci due to the presence of calcification

  • Submucosal leiomyomas may mimic endometrial lesions on US – US HSG may aid in the diagnosis

CT

A fibroid has a soft tissue density similar to that of normal myometrium ▸ necrosis or degeneration may result in low attenuation (± calcification or uterine contour deformity)

MRI

This allows the precise determination of the size, location and number of leiomyomas ▸ it can differentiate a pedunculated subserosal leiomyoma from an adnexal mass

  • T1WI: well-circumscribed, rounded lesions with intermediate SI

  • T1WI (FS): this can demonstrate haemorrhagic degeneration (with high SI)

  • T1WI + Gad: the enhancement is less than that of the adjacent myometrium ▸ any degenerated areas may not enhance

  • T2WI: there is lower SI relative to the myometrium or endometrium ▸ signal voids represent calcification or vessels

  • Cystic degeneration: well-defined non-enhancing areas of fluid density ▸ myxoid degeneration: very high signal on T2WI (non-enhancing) ▸ red degeneration: massive haemorrhagic infarction + necrosis (peripheral low T2WI rim + high T1WI signal)

Pearl

  • Treatment: hysterectomy, myomectomy or uterine arterial embolization (UAE) ▸ MR-guided ultrasound ablation is a recent innovation

Variable appearance of fibroids on MRI. (A) Sagittal T2-weighted MRI showing an intermediate signal anterior myometrial fibroid. Patchy high signal areas indicate degeneration. A second fibroid at the fundus is of characteristic low signal. (B) There is cystic degeneration in the anterior fibroid, and a low signal intensity posterior fibroid that has displaced the rectum. Note retroverted uterus. (C) A large pedunculated fibroid is of mixed signal, indicating degeneration. Note multiple small low signal fibroids in the myometrium. **

Myxoid and red degeneration of fibroids on MRI. (A) Axial T2-weighted image. There is myxoid degeneration of a large fibroid with central very high signal. (*) A second fibroid on the right is of mixed signal. (B) Red degeneration with massive haemorrhagic infarction and necrosis of the entire leiomyoma, with a peripheral rim of low signal on this coronal T2-weighted image. Note also left hydrosalpinx (arrow). **

Endometrial Polyps

Definition

  • A benign polypoid tumour consisting of a stromal core with the mucosal surface projecting above the level of the adjacent endometrium

  • Although it can occur at any age, it is commonest in older (>50 years) females

Radiological Features

TVS

This will often not reveal any endometrial polyps

US HSG

The homogeneous polyp is isoechoic to (and continuous with) the endometrium ▸ there is a preserved endomyometrial interface ▸ there can be central cystic areas and feeding vessels (best seen with colour Doppler)

MRI

This is rarely employed due to the high cost ▸ T1WI: the polyp is isointense to the endometrium (± hypointense foci) ▸ T2WI: the polyp is hypo- to isointense to the endometrium (± cystic changes) ▸ if pedunculated there can be a central hypointense core (± a stalk) ▸ T1WI + Gad: there is homogeneous or heterogeneous enhancement

Hysteroscopy

The diagnostic technique of choice

Pearl

  • Differential: submucosal leiomyoma ▸ malignant neoplasm

Saline hysterography. Endometrial polyp outlined by saline. †

TVUS. Multiple endometrial polyps. Note the midline echoes due to the endometrial interface (arrows) displaced by the polyps. This is a useful feature in differentiating polyps from endometrial hyperplasia. †

Adenomyosis

Definition

  • The presence of endometrial tissue within the myometrium, with secondary smooth muscle hypertrophy and hyperplasia

  • It can be diffuse or focal, and is seen in 15–27% of hysterectomy specimens (there is an increased incidence in multiparous women)

Clinical presentation

  • Dysmenorrhoea and dysfunctional uterine bleeding

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts