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Genitourinary Imaging---Uterus

Bin Fu

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rectum

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Radiograph, contrast media, hysterogram, AP projection.

Uterine body

Fallopian tube

Uterine fundus

Cervix

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Female genital organs CT, axial section. (10. Ovary 18. Sacrum, 24. Urinary bladder25. Urinary bladder, detrusor of, 30. Uterine fundus, 33. Uterus)

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cavitary uteri

Uterine body

Urinary bladder

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MR Imaging Appearance of Normal Uterus Anatomy

On T1WI, the normal Uterus demonstrates homogeneous intermediate-to-low signal intensity.

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Uterine Zonal Anatomy (on T2WI) Thickness of zones depends on menstrual cycle +

hormonal medication ENDOMETRIUM high signal intensity similar to fat JUNCTIONAL ZONE low signal MYOMETRIUM

intermediate signal intensity Outer Surface of Uterus thin low-signal intensity line

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Female genital organs MRI, T2WI, sagittal section. (3. Endometrium 11 Pelvic floor 13. Pelvis true (true pelvis) 14. Promontory of sacrum 15. Pubic symphysis 16 Rectouterine pouch 17. Rectum 24. Urinary bladder)

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Cervix

Uterine bodyEndometrium

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MRI, T2WI

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Uterine leiomyoma

Uterine leiomyoma is a benign tumor of smooth muscle cell origin.

It is typically a well-circumscribed tumor containing smooth muscle and a variable amount of fibrous tissue.

Leiomyomas are classified by their position in relation to the uterine wall as submucosal, intramural (or interstitial) or subserosal.

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Uterin

e leiom

yom

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subserosal

pedunculated

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Uterine leiomyoma Uterine leiomyomas are the most common femal

e pelvic tumor, occurring in up to 40% of women by the fifth decade of life.

Leiomyomas shrink and may calcify after the menopause.

New leiomyomas are rare in the postmenopausal female.

Sometimes leiomyomas undergo a rapid increase in size during pregnancy.

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Uterine leiomyoma

These features suggest the tumor is oestrogen dependent, but the exact aetiology is unknown.

They may be single, but are usually multiple.

Size is also variable; leiomyomas can be microscopic or result in gross uterine enlargement.

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Uterine leiomyoma Symptoms usually arise from pressure effects du

e to the large pelvic mass. It may also present with pelvic pain, dysmenorrh

oea and abnormal uterine bleeding. Submucosal leiomyomas project into the uterine

cavity and may cause infertility, recurrent abortion, or hypermenorrhoea.

Intramural leiomyomas may also be associated with infertility.

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Uterine leiomyoma Depending on their size and location, both subm

ucosal and intramural leiomyomas may obstruct labour.

Subserosal leiomyomas are exophytic from the uterus and may undergo torsion and present with acute abdominal pain.

Occasionally, leiomyomas are the only identifiable abnormality after a detailed infertility work-up, and in such cases, myomectomy has been reported to result in a successful term pregnancy rate of 40~50%.

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CT features of uterine leiomyomas

CT features of uterine leiomyomas include a focal solid mass causing lobulation or protrusion from the outer margin of the uterus, or distorting or obliterating the uterine cavity.

Focal calcifications and irregular low-density areas in the mass are also suggestive.

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MRI features of uterine leiomyomas

At MRI, leiomyomas appear as well-circumscribed masses of similar or slightly low T1 signal intensity and homogeneously low T2 signal intensity, relative to the adjacent myometrium.

Slight slow diffuse homogeneous enhancement may occur after intravenous gadolinium chelates.

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Uterine leiomyoma Sagittal T2WI image demonstrating a large intramural leiomyoma in the posterior uterine wall (arrow).

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Uterine leiomyoma Sagittal T2WI section through the pelvis demonstrating a submucosal leiomyoma arising from the anterior wall of the endometrial cavity (arrow).

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Uterine leiomyoma Sagittal T2WI section through the pelvis showing a giant leiomyoma (arrow) of the anterior uterine wall.

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Uterine leiomyoma Sagittal T2WI section showing a intramural leiomyoma in the posterior uterine wall. The high signal intensity on T2 images indicates degenerative change.

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Uterine leiomyomas MRI is indicated when ultrasound results are limi

ted or inconclusive. Sonography has been reported to result in false

negative results in 22% of cases. US is particularly limited when the tumor is small

(less than 2 cm in diameter), or very large when the uterus is retroverted or duplicated and when there is coexisting adnexal or pelvic pathology.

MRI is especially useful in the search for leiomyomas in the infertile patient.

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Uterine leiomyomas Furthermore, it is possible to differentiate betwee

n leiomyoma and adenomyosis with MR imaging.

MRI may also be used prior to myomectomy when the location and precise size of leiomyomas need to be known.

Serial MR images can also facilitate an assessment of response to hormone analogue treatment.

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Uterine leiomyomas

MR imaging is considered superior to US in the evaluation of uterine leiomyoma with a reported sensitivity of 92%.

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Uterine leiomyomas Treatment of leiomyomas depends on thei

r size and location. Small submucosal lesions may be remove

d hysteroscopically. Intramural tumors are removed by myome

ctomy, particularly in women desiring uterine preservation or pregnancy.

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Cervix carcinoma Carcinoma of the cervix can occur at any a

ge from menarche onwards. The peak incidence is premenopausal: ear

ly 30s for in situ lesions and early 40s for invasive disease.

Cervical carcinoma is rare before the age of 30 years.

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Cervix carcinoma Risk factors for the development of cervica

l carcinoma include early age at first intercourse, multiple sexual partners, and low socioeconomic status.

Perhaps the most important risk factor is exposure to specific subtypes of the human papillomavirus.

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Cervix carcinoma The two major symptoms of cervical carcinoma

are vaginal bleeding and discharge. It is of note, however, that up to 20% of patients

with invasive cervical carcinoma are asymptomatic at the time of diagnosis.

Pelvic pain and urinary frequency are less common presenting symptoms, usually associated with advanced disease.

The majority of noninvasive or early stage disease is most likely to be discovered in asymptomatic females with abnormal cervical cytology.

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Cervix carcinoma Approximately 90% of cervical malignancie

s are squamous cell carcinomas. The remaining 10% of cervical cancers con

sist of adenocarcinomas and sarcomas. The majority of cervical carcinomas occur a

t the squamocolumnar junction.

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Cervix carcinoma Early spread of invasive cervical carcinoma is ty

pically by direct extension and lymphatic invasion.

Lateral spread into the parametrium typically occurs prior to anterior or posterior extension, due to the lack of restraining fascial planes.

With disease progression, there is extension into the upper vagina and/or uterine myometrium.

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Cervix carcinoma Direct invasion of the rectum, sigmoid colo

n, urinary bladder, ureters, and pelvic side wall generally occurs late in the disease.

Rarely, invasive cervical carcinoma can extend posteriorly into the pelvic cul-de-sac, resulting in peritoneal dissemination.

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Cervix carcinoma Lymphatic spread typically occurs in an orderly f

ashion, initially involving the parametrial, obturator, internal iliac, external iliac and lateral sacral nodes.

The disease eventually progresses to involve common iliac chain and para-aortic nodes.

Spread into the mediastinum or supraclavicular nodes can occur with extensive disease.

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Cervix carcinoma Haematogenous dissemination is a relatively lat

e event in the course of invasive cervical carcinoma.

These are typically secondary to direct venous invasion or anastamoses between the lymphatics and venous system.

Common sites of metastatic spread in order of frequency include the lung, skeletal system, brain and liver.

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Cervix carcinoma CT has become increasingly popular in the

evaluation of clinically advanced disease. CT has the ability to demonstrate the prim

ary tumor, as well as other important sta reliable of these signs is obliteration of the periureteric fat plane, usually a late finding with gross parametrial invasion.

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Cervix carcinoma CT is useful in detecting pelvic side wall invasion.

Extension of tumor to within 3 mm of the pelvic side wall, encasement of the iliac vessels, or enlargement of the obturator or piriformis muscles are all signs of stage III disease.

Gross invasion of the bladder or rectum (stage IV) is usually seen as loss of fat planes and irregular wall thickening.

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The overall accuracy of detecting pelvic nodal metastases is between 70 and 80%.

CT is the most popular modality for guiding percutaneous biopsy of suspicious lymph nodes.

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MRI imaging The superior contrast resolution of MRI ma

kes it an ideal modality for evaluation of cervical carcinoma.

Cervical carcinoma is identified as a high signal intensity mass on T2WI.

This is in stark contrast to the low signal of normal cervical stroma.

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Cervix carcinoma Axial T2WI through the cervix in a patient with endocervical carcinoma. An irregular infiltrative mass (arrow) is evident, with a lobulated lateral margin consistent with paracervical extension.

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Cervix carcinoma Sagittal T2WI demonstrates a large mass in the cervix (arrow). Layering fluid is seen in the endometrial cavity, due to the obstructive effect of the tumor.

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Cervix carcinoma Sagittal T2WI showing a large carcinoma of the cervix, with extension to involve the corpus uteri.

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The cervical mass is much less conspicuous on T1WI, as the mass and normal cervix often demonstrate similar signal intensity.

Intravenous gadolinium chelates cause variable tumor enhancement.

Contrast enhancement can differentiate between viable and necrotic tumor.

The use of contrast, however, has not shown any improvement in overall accuracy of tumor depiction.

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MRI is very useful in the determination of tumor size.

One of the seemingly universal principles of oncology is that tumor volume generally correlates with prognosis.

Excellent contrast resolution between tumor and normal cervical tissue allows accurate measurements.

MR imaging has been shown to be up to 93% accurate in measuring tumor size to within 5 mm of measurements obtained from surgical specimens.

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Lesion measurement by MRI is useful when determination of tumor size is difficult or equivocal by physical examination.

In addition to determining lesion size, MR imaging is useful in the local staging of cervical cancer.

MRI can identify deep stromal invasion with a 94% accuracy.

MRI is less reliable in the depiction of lesions with superficial stromal invasion.

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Overall, MR is 88% accurate in determining the presence of stromal invasion and 78% accurate as to the depth of stromal invasion.

MRI is useful in the evaluation of parametrial invasion.

In addition to full depth cervical stromal invasion, MR imaging findings of parametrial invasion include an asymmetrical tumor bulge, irregular tumor parametrial interface, and vascular encasement.

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MRI is also accurate in the depiction of lower vaginal involvement, ureteric obstruction, and pelvic side wall invasion.

MRI findings of pelvic side wall invasion include tumor proximity to the side wall less than 3 mm, vascular encasement, and increased signal of adjacent muscle on T2WI.

The sagittal plane is useful in detecting rectal, urinary bladder, or lower vaginal involvement.

The MRI findings in bladder invasion include direct tumor invasion or increased signal within the bladder wall on T2WI.

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Thank you!