During menstruation---- a thin echogenic line, 1–4 mm
In early proliferative phase of the menstrual cycle(after
day 6) becomes thicker (5–7 mm) and more echogenic
relative to the myometrium, (glands, blood vessels, and
Late proliferative (periovulatory) phase
a multilayered appearance.
an echogenic basal layer and hypoechoic inner
functional layer, separated by a thin echogenic
may measure up to 11 mm in thickness.
During the secretory phase, becomes even thicker (7–
16 mm) and more echogenic .
stromal edema and glands distended with mucus
increased posterior acoustic enhancement.
The endometrium typically reaches a maximum
thickness during the mid secretory phase .
Endometrial thickness is measured from echogenic
border to echogenic border across the endometrial
cavity on a sagittal midline image.
Normal premenopausal endometrium. Sagittal US image of the
uterus obtained during menstruation shows a thin endometrial
lining with a trace of fluid.
Normal premenopausal endometrium. Sagittal US image of the uterus
obtained during the late proliferative phase of the menstrual cycle
demonstrates the endometrium with a multilayered appearance .
uterus has homogeneous intermediate signal intensity
with T1-weighted sequences.
T2-weighted images delineate the uterine zonal
So endometrium is best visualized on T2.
The normal endometrium is of uniformly high signal
intensity, and the inner myometrium, or junctional
zone, is of uniformly low signal intensity
Normal premenopausal endometrium. T2-weighted MR image shows
the normal endometrium and junctional zone.
should be thin, homogeneous, and echogenic.
Homogeneous, smooth endometria measuring 5 mm
or less are considered within the normal range with or
without hormonal replacement therapy.
The endometrium in a patient undergoing hormonal
replacement therapy may vary up to 3 mm if cyclic
estrogen and progestin therapy is being used
Postmenopausal endometrial atrophy. Transvaginal US image
demonstrates a postmenopausal endometrium with thin walls and
outlined with fluid.
a common cause of postmenopausal bleeding
most frequently seen in patients receiving tamoxifen or
may be broad-based and sessile or pedunculated.
Typically measure 5-15mm.
The point of attachment should not disrupt the
frequently identified as focal masses within the
endometrial canal. OR
as nonspecific endometrial thickening.
Color Doppler US may be used to image vessels within
Polyps are best seen at sonohysterography
appear as echogenic, smooth, intracavitary masses
outlined by fluid
seen as pedunculated filling defects within the uterine
T2-weighted MR imaging
Appears as low-signal-intensity intracavitary masses
surrounded by high-signal-intensity fluid and
Sonohysterogram reveals a small polyp attached by a stalk to the
Anteroposterior (left) and oblique (right) hysterosalpingograms
demonstrate a pedunculated filling defect within the uterine cavity
T2-weighted MR image demonstrates a low-signal-intensity lesion
within the endometrial canal (arrow).
A definitive diagnosis can be made only with biopsy
imaging cannot reliably allow differentiation
between hyperplasia and carcinoma.
Up to one-third of endometrial carcinoma is believed
to be preceded by hyperplasia.
On histology, three types of endometrial hyperplasia
(cystic, adenomatous, atypical)
All types can cause diffusely smooth or, less
commonly, focal hyperechoic endometrial
Endometrial hyperplasia is considered
when the endometrium exceeds 10 mm in thickness,
especially in menopausal patients
In postmenopausal women 5mm thickness is
may also cause asymmetric thickening with surface
irregularity, an appearance that is suspicious for
The US appearance can simulate that of normal
thickening during the secretory phase, sessile polyps,
submucosal fibroids, cancer, and adherent blood
clots, yielding potentially false-positive results .
Because endometrial hyperplasia has a nonspecific
appearance, any focal abnormality should lead to
biopsy if there is clinical suspicion for malignancy.
Endometrial hyperplasia. US image shows an endometrium with
diffuse thickening (maximum thickness, 1.74 cm) due to
hyperplasia. This finding was confirmed at biopsy.
Fourth most common malignancy in females.
Most common malignancy of the female
The prevalence of endometrial cancer is increasing
with rising levels of obesity.
App. 75% cases occur in postmenopausal women,
median age at diagnosis is 70 years.
Postmenopausal bleeding—most common symptom.
Adenocarcinomas account for 90% of endometrial
uterine sarcomas-- only 2%–6%;
remaining include adenocarcinoma with squamous
cell differentiation and adenosquamous carcinoma.
depth of myometrial invasion,
histologic grade, and
Depth of myometrial invasion is the most important
morphologic prognostic factor, correlating with
tumor grade, presence of lymph node metastases,
and overall patient survival.
3% lymph node metastases with superficial
myometrial invasion to 46% with deep myometrial
Endometrial cancer is staged with the International
Federation of Gynecology and Obstetrics (FIGO)
system, which recently underwent a major revision.
First proposed in 1988, and the staging system was
updated in 2009.
The previous iteration of the FIGO system
subdivided stage I tumors into IA, IB, and IC tumors.
Stage IA tumors are confined to the endometrial
stage IB tumors invade <50% of the depth of the
stage IC tumors invade ≥50% of the depth of the
In the 2009 revised FIGO staging system,
tumors confined to the endometrium as well as those
invading the inner half of the myometrium are
designated as stage IA tumors,
tumors invading the outer half of the myometrium
are designated as stage IB tumors.
These changes may improve the diagnostic accuracy
of MR imaging.
With the old staging system, differentiating between
stage IA and IB tumors could be challenging in
patients with loss of junctional zone definition or in
lesions with poor tumor-to-myometrium contrast.
Stage II tumors were previously subdivided into
stage IIA and IIB tumors,
IIA tumors were characterized by endocervical
glandular invasion and
IIB tumors by cervical stromal invasion.
Stage III is composed of three subdivisions:
Stage IIIA tumors invade the serosa or adnexa ,
Stage IIIB tumors invade the vagina or
Previously, stage IIIC referred to any
lymphadenopathy (pelvic or retroperitoneal);
In the new FIGO system, however, stage IIIC is divided
stage IIIC1-- characterized by pelvic lymph node
stage IIIC2-- characterized by paraaortic lymph node
Stage IVA tumors extend into adjacent bladder or
Stage IVB tumors have distant metastases (eg, to the
liver or lungs)
Ideal imaging modality for staging of endometrial Ca.
an important predictor of lymph node metastases.
also allow accurate assessment of more advanced
disease such as cervical stromal invasion or adnexal
Diffusion-weighted and Dynamic Contrast-enhanced
Have improved the staging accuracy
allow tumor to be distinguished from blood products
Endometrial tumors enhance earlier than does normal
Normal myometrium enhances intensely compared
with hypointense endometrial tumor.
MR Imaging Appearances
On unenhanced T1-weighted images, Endometrial
cancer is isointense relative to hypointense normal
On T2-weighted images, shows heterogeneous
intermediate signal intensity relative to hyperintense
Relative to normal myometrium, the tumor is mildly
hyperintense on T2-weighted images.
At conventional MR imaging, the depth of
myometrial invasion is optimally depicted with T2-
Stage IA endometrial cancer in a 35-year-old woman. Sagittal T2-
weighted MR image shows distention of the endometrial cavity by an
intermediate-signal-intensity tumor .
On an axial oblique contrast-enhanced MR image, the tumor is
hypoenhancing relative to the hyperenhancing myometrium and
appears to be confined to the endometrium.
Stage IA endometrial cancer in a 61-year-old woman. Sagittal T2-
weighted MR image shows distention of the endometrial cavity by an
intermediate-signal-intensity tumor. Poor tumor-to-myometrium
contrast is seen inferiorly.
Sagittal contrast-enhanced MR image demonstrates excellent contrast
between the hyperenhancing myometrium and the endometrial tumor ,
which appears to be confined to the endometrial cavity .
Stage IB. Axial oblique contrast-enhanced MR image shows tumor
enhancement with invasion of the outer half of the myometrium .
Stage II endometrial cancer in a 64-year-old woman.Sagittal contrast-
enhanced MR image shows extension of the endometrial tumor into the
cervix. Invasion of the cervical stroma is present posteriorly and is better
appreciated than on the T2-weighted image.
Stage IIIA endometrial cancer in a 65-year-old woman.Axial oblique T2-
weighted MR image shows extension of the endometrial tumor into
both fallopian tubes (arrows). The tumor is isointense relative to the
Stage IIIA endometrial cancer in a 65-year-old woman.Axial oblique
dynamic contrast-enhanced MR image shows enhancement of the
tumor extension into the fallopian tubes . The primary tumor enhances
less than the adjacent myometrium
Stage IIIC1 endometrial cancer in a 66-year-old woman.On an axial
dynamic contrast-enhanced MRI the node (N) demonstrates avid
Stage IVA endometrial cancer in a 72-year-old woman. Sagittal T2-
weighted MR image shows a large endometrial tumor with invasion of
the sigmoid colon as evidenced by loss of the normal fat plane between
the tumor and colon .