Female Reproductive System IMAGING

Female Reproductive Anatomy

Cervical Os

Female Reproductive System Imaging and Procedures

HSG

SAGITTAL T2WI MRI U: UTERS (BIGHT ENDOMETIUM, DARK JUNCTIONAL ZONE, LIGHT DARK MYOMETRIUM) C: CERVIX B: BLADDER R: RECTUM

CORONAL T2WI MRI O: OVARIES U: UTERUS B: BLADDER O O U B

Figure 1.  Normal uterus. Figure 1.  Normal uterus. Sagittal endovaginal US scan shows a normal myometrium (M), which is moderately echogenic and has a homogeneous echotexture. The subendometrial halo, which represents the innermost layer of the myometrium, is visualized subjacent to the endometrium (E) as a thin hypoechoic band (arrows). The endometrium is uniformly echogenic in this patient, who was in the secretory phase of the menstrual cycle. Reinhold C et al. Radiographics 1999;19:S147-S160 ©1999 by Radiological Society of North America

Congenital Anomolies (FEMALE)

Uterus Didelphys

Unicornate Uterus Pathology There is failure of one müllerian duct to elongate while the other develops normally. The embryologic predominance of the unicornuate uterus to be on the right has not been explained. It may or may not have rudimentary horn.  

Hysterosalpingogram (HSG) The endometrial cavity usually assumes a fusiform (banana type) shape (except for type a where there may a small cavitatory filling defect), tapering at the apex and draining into a solitary fallopian tube. The uterus is generally shifted off the midline.

Unicornuate Uterus

MRI unicornuate uterus appears curved and elongated, with the external uterine contour assuming a banana shape uterine volume is reduced, and the configuration of the uterus is asymmetric normal myometrial zonal anatomy is maintained  

MRI obtained subsequent to hysterosalpingography MRI obtained subsequent to hysterosalpingography. Axial T2 MRI shows fusiform uterine cavity with typical trilaminar appearance of high-signal endometrium (star), low-signal junctional zone (long arrow), and intermediate-signal myometrium (short arrow) of uterus seen in right side of pelvis. This corresponds to cavity opacified on 

septate uterus 12 : has a normal fundal contour but is characterized by a persistent longitudinal septum that partially divides the uterine cavity  

Bicornate Uterus Pathology It results from an abnormal development of the paramesonephric ducts that results in a uterus divided into two horns from a partial failure of fusion. bicornuate bicollis : two cervical canals - central myometrium extends to external cervical os bicornuate unicollis : one cervical canal - central myometrium extends to internal cervical os

Radiographic features General The external uterine contour is concave or heart shaped, and the uterine horns are widely divergent. The fundal cleft is typically more than 1cm deep and the inter-cornual distance is widened.

Fluoroscopy - Hysterosalpinogram (HSG) Difficult to differentiate between septate and bicornuate anomalies due to the outer uterine contour not being visible 5. MRI May help confirm anatomy by showing a deep (> 1 cm) fundal cleft in the outer uterine contour and an inter-cornual distance of more than 4 cm. The uterus demonstrates normal uterine zonal anatomy. 

Bicornate Uterus

Uterus Didelphys Uterus didelphys with an obstructed hemivagina. (a) Axial T2-weighted image shows two separate uteri and two cervices (arrows), all of which have normal zonal anatomy. Arrowheads = ovaries

uterus didelphys  It results from failed ductal fusion that occurs between the 12th and 16th week of pregnancy and is characterized by two symmetric, widely divergent uterine horns and two cervixes. The uterine volume in each duplicated segment is reduced.

Hysterosalpingogram (HSG) HSG demonstrates two separate endocervical canals that open into separate fusiform endometrial cavities, with no communication between the two horns. Each endometrial cavity ends in a solitary fallopian tube. If the anomaly is associated with an obstructed longitudinal vaginal septum, only one cervical os may be depicted, and it may be cannulated with the endometrial configuration mimicking a unicornuate uterus.

Pelvic ultrasound Separate divergent uterine horns are identified with a large fundal cleft. Endometrial cavities are uniformly separate, with no evidence of communication. Two separate cervices need to be documented. MRI MR imaging demonstrates two separate uteri with widely divergent apices, two separate cervices, and usually an upper vaginal longitudinal septum. In each uterus, normal uterine zonal anatomy is preserved

Neoplastic Diseases (FEMALE)

Endometriosis

Endometriotic cysts (endometriomas or "chocolate cysts") most commonly occur in the ovaries and are the result of repeated cyclic haemorrhage within a deep implant. Often there is complete replacement of ovarian tissue. The cyst walls may become thick and fibrotic with dense adhesions, with lining that varies in contour (smooth to shaggy) and colour (pale to brown).  

haemorrhagic “powder burn” lesions appear bright on T1 fat saturated sequences. small solid deep lesions may be hyperintense on T1 and low on T2 endometriomas < 5 mm: early stage disease; > 15 mm: advanced disease shading sign 25: may be less likely to respond to medical treatment 28 low T1 and T2 due to tissue and haemosiderin laden macrophages 1 diagnostic criteria: multiple cysts with T1 hyperintensity OR one or more cysts with high T1 and shading on T2

Hemorrhagic cyst of the right ovary in a 21-year-old woman. Hemorrhagic cyst of the right ovary in a 21-year-old woman. Transverse endovaginal sonogram reveals fibrinous strands (arrow) and low-level internal echoes. The margins of the ovary are marked with electronic cursors (+, ×). Both reviewers made the correct diagnosis. Patel M D et al. Radiology 1999;210:739-745 ©1999 by Radiological Society of North America

Figure 15a. Bilateral endometriomas in a 27-year-old woman. Figure 15a.  Bilateral endometriomas in a 27-year-old woman. (a) Axial T1-weighted MR image shows bilateral high-signal-intensity adnexal masses (solid arrows). An intrauterine device is seen within the uterus (open arrow). (b) On a T1-weighted fat-suppressed image, these masses remain bright, a finding that effectively rules out a diagnosis of dermoid cyst. (c) T2-weighted image shows shading with mixed high and low signal intensity in both lesions (arrows). Open arrow = intrauterine device. Woodward P J et al. Radiographics 2001;21:193-216 ©2001 by Radiological Society of North America

ADENOMYOSIS Adenomyosis is a nonneoplastic condition, characterized by benign invasion of ectopic endometrium into the myometrium with hyperplasia of adjacent smooth muscle.

Figure 2a. Imaging signs of adenomyosis. Figure 2a.  Imaging signs of adenomyosis. E = endometrium. (a) Sagittal oblique endovaginal US scan shows that the myometrium is thickened ventrally and has a heterogeneous echotexture (straight arrows). The echogenicity of the ventral myometrium is decreased relative to that of the dorsal myometrium. Additional features of adenomyosis seen in this image include poor definition of the endomyometrial junction and a myometrial cyst (curved arrow). (b) Corresponding sagittal T2-weighted MR image shows marked thickening of the junctional zone. The result is a poorly defined low-signal-intensity mass that replaces the ventral myometrium (arrows). The numerous bright foci, some of which have a rounded appearance whereas others have a linear or fingerlike appearance, represent the heterotopic endometrium. Bl = bladder Reinhold C et al. Radiographics 1999;19:S147-S160 ©1999 by Radiological Society of North America

Uterine Fibroid They are benign growths, arising from the muscular wall of the uterus. Their origin is thought to be the muscle in the walls of uterine blood vessels. Fibroids vary greatly in size, and can remain for years with little change. Others can grow much larger and reach the size of a 5 month pregnancy or more. In pregnancy, pre-existing fibroids can increase 3-5 times in size. This is thought to be due in part to the very high estrogen level in pregnancy, as well as to other factors stimulating the pregnancy changes. Quite remarkably after pregnancy, these same fibroids can shrink to their pre-pregnancy size. Menopausal patients who take estrogen show a varying response. Some who start with significant size fibroids may notice a slow increase in size, while others experience very little change at all. Fibroids are extremely common. They are estimated to reach significant size in 25-30% of all Caucasians, and in 50% of women of African background. If very tiny fibroids are included, some studies suggest that by the menopause virtually every woman has them. In most cases, there is more than one fibroid present. Sometimes there are many - 50 or more have been counted. A Solitary fibroid can occur, but is much less frequent. Cancer in a fibroid is very uncommon (perhaps 1:750 to 1000). There is some data that suggests this cancer (called a sarcoma) may not arise from a pre-existing fibroid at all, but develop in an area of the uterus not a fibroid. Fibroids are also called by other names such as: Myoma, Leiomyoma, Leiomyomata and Fibromyoma Serosal Fibroids (or those which develop in the outer portion of the uterus and expand giving the uterus a "knobby" appearance.) A serosal fibroid develops below the capsule of the uterus, and slowly expands outwards. (Observe the animated drawing to the left.) Probably because they are not trapped below the surface of the uterus, they can expand to large size. They produce no change in menstrual flow, and no increase in the miscarriage rate. They are compatible with pregnancy (though because of their size they can become uncomfortable by causing increasing pressure). Serosal fibroids produce a problem in pregnancy only if they are in the lower part of the uterus. There they can block the outlet of the pelvis making a C-Section the only way to deliver the baby. Intra-Mural Fibroids (or those which develop within the wall of the uterus and expand making the uterus feel larger than normal during a pelvic exam.) An Intra-mural fibroid develops below the capsule of the uterus, and slowly expands, increasing the bulk of the uterus. (Observe the animated drawing to the left.) When there are many fibroids within the wall, the uterine cavity also expands. This can result in heavier menstrual flows. Should the combined bulk of the fibroids (all types) be large enough to fill the pelvis tightly, a blockage of flow of urine from the kidneys may result. Though this is uncommon, it can damage the kidneys if left untreated. Hence once this blockage is discovered, these fibroids must be removed

A uterine leiomyoma (uterine fibroid) is a benign tumour of myometrial (smooth muscle) origin. It is the most common solid benign uterine neoplasm pidemiology They occur in ~ 20 - 30% of women of reproductive age 1 and are particularly common in the African population .

a number of locations within or out of the uterus : Within the uterus intra-mural leiomyoma : most common sub-serosal leiomyoma sub-mucosal leiomyoma : least common : ~ 10 - 15 % They can also undergo several types of degeneration hyaline degeneration, cystic degeneration myxoid degeneration, red - carneous extra uterine pelvic leiomyomas7

Pelvic ultrasound ultrasound is used to diagnose the presence and monitor the growth of fibroids uncomplicated leiomyomas are usually hypo-echoic. calcification is seen as echogenic foci with shadowing cystic areas of necrosis / degeneration may be seen

they may distort the usually smooth uterine contour CT on CT images, fibroids are usually of soft tissue density but may exhibit coarse peripheral or central calcification they may distort the usually smooth uterine contour enhancement pattern is variable Pelvic MRI Signal characteristics are variable, and include 1-2 T1 : non-degenerated fibroids and calcification appear as low to intermediate signal intensity compared with the normal myometrium

T2 : non-degenerated fibroids and calcification appear as low signal intensity  as they are usually hypervascular, flow voids are often observed around them 10 fibroids that have undergone cystic degeneration / necrosis can have a variable appearance, usually appearing high signal on T2 sequences. T1 C+ (Gd) : variable enhancement is seen with contrast administration

LEIOMYOMA (FIBROID TUMOR) Due to the presence of needles, and possibly also due to her long-term disability, the patient has chronic ileus, causing severe constipation and stool impaction. By the way, the lesion projecting over the right iliac wing is a calcified leiomyoma uteri. The uterus is displaced to the right by the stool-distended sigmoid colon.