Download [2015.91] Pre-Operative MRI of Endometrial Cancer: Clinically

Pre-operative MRI of Endometrial Cancer:
Clinically relevant findings and pitfalls to avoid.
Krupa Patel-Lippmann, MD1
Kristie Guite, MD1
Jessica Robbins, MD1
Ahmed Al-Niaimi, MD2
Elizabeth Sadowski, MD1
University of Wisconsin
SCHOOL OF MEDICINE
AND PUBLIC HEALTH
Department of Radiology1
Department of Obstetrics and Gynecology-UW2
Disclosures
No disclosures to report.
Objectives
 Overview of normal MRI uterine anatomy
 Describe MR imaging features and staging of endometrial
cancer
 Learn to differentiate the appearance of endometrial cancer
from endometrial hyperplasia, adenomyosis, fibroids, and
polyps
 Highlight common pitfalls encountered in the MRI assessment
of endometrial cancer
Introduction
 Endometrial cancer
 4th most common cancer in women
 Most common gynecologic malignancy
 Peak incidence: 55 and 65 years
 Risk factors
 Obesity
 Nulliparity
 Late menopause
 Unopposed estrogen exposure
 Tamoxifen
Introduction
 Over 80% of patients present with early stage disease due to symptoms
of abnormal uterine bleeding, with an overall excellent prognosis.
 Endometrial cancer is traditionally surgically staged and the treatment
varies by stage, grade, regional guidelines, and expertise.
 MRI is a valuable adjunct to pre-operative planning as it can accurately
depict endometrial cancer . The goal of MRI is to identify patients preoperatively who would benefit from abdominopelvic lymph node
dissection and adjuvant therapy while avoiding overtreating early stage
patients with unnecessary lymphadenectomies.
MRI Protocol
T2
T1-post
T1
T2
Preparation
 To minimize bowel motion consider
 Fasting for 4-6 hours prior to the study
 Anti-peristaltic medications prior to exam
 Empty bladder to avoid motion artifact
Basic Protocol




Torso or Cardiac Coil
Axial/ Sagittal T1-pre and -post contrast images DWI
Axial/Sagittal T2-wt images with fat saturation
Dynamic contrast enhanced images - 40 and 90
sec
 Axial and sagittal diffusion weighted images
B=0
B=500
Figure: Sagittal T2-wt, sagittal T1-post contrast,
axial T1-wt, axial T2-wt, and diffusion weighted
imaging of the pelvis. These images demonstrate
a mass within the endometrial cavity ( ).
ADC
Normal MRI Uterine Anatomy
T2
 Uterus has three distinct
layers
 Endometrium
 Junctional zone
 Myometrium
 Anatomy best delineated
on T2-wt images
m
cs
jz
ec
e
GUCXM3
v
r
b
Figure: Sagittal T2-wt fat-saturated image demonstrates the
normal trilaminar appearance of the uterus. The T2 hyperintense
endometrium (e), the hypointense junctional zone (jz), and
isointense myometrium (m) creates the trilaminar appearance.
The cervix demonstrates a hyperintense endocervical canal and
hypointense cervical (cs) stroma. Bladder (b), vagina (v), rectum
(r).
Endometrial Cancer Staging and Grading
Risk stratification and treatment planning is based on tumor histology and tumor stage.
 Tumor Histology : pre-operative from
endometrial biopsy
 Tumor grade: I-III (well -poorly differentiated)
 Tumor cell type: 90% adenocarcinoma with
endometroid subtype. Clear cell and papillary
serous carcinoma have a worse prognosis.
 Tumor Stage : surgically staged in the OR
 Based on 2009 International Federation of
Gynecologic and Obstetrics (FIGO) Surgical
Staging System
 Full staging consists of total abdominal
hysterectomy, bilateral salpingooophorectomy, peritoneal washings, and
retroperitoneal lymph node dissection
 Key prognostic factors are depth of
myometrial invasion( MI), cervical stromal
invasion, and lymphovascular invasion (LVSI)
FIGO 2009 Surgical Staging System
Stage
IA
IB
II
IIIA
IIIB
IIIC1
IIIC2
IVA
IVB
Description
Tumor confined to uterus, <50% MI
Tumor confined to uterus, ≥50% MI
Cervical stromal invasion
Tumor invasion into serosa or adnexa
Vaginal or parametrial involvement
Pelvic node involvement
Para-aortic node involvement
Tumor invasion into bladder/bowel mucosa
Distant metastases
Figure modified from: Beddy et al. FIGO Staging System for Endometrial Cancer. RadioGraphics 2012
Preoperative MRI and Surgical Management
 Goals of MRI
 Depict endometrial cancer origin (endometrial vs endocervical)
 Determine the depth of myometrial invasion (MI)
 Most important morphologic prognostic factor
 Prevalence of lymph node metastasis increases from 3%
with superficial MI to 46% with deep MI
 Sensitivity/sensitivity of MRI for MI approaches 94%/100%
 Evaluate for cervical stromal involvement (CI) and extra-uterine
spread
 Sensitivity and specificity of MRI for CI approaches
96%/80% respectively
 Additional imaging features (uterine size, tumor volume, ascites
and adnexal disease) may also determine surgical approach
(open laparotomy vs transvaginal vs laparoscopic; +/lymphadenectomy)
 Overall reported accuracy of MRI for endometrial cancer staging
approaches 93%
Grade 1/2:
If there is greater than
50% MI, positive cervical
or extrauterine spread,
the risk of lymph node
metastasis increases and
lymphadenectomy is
performed at some
institutions.
Grade 3:
MRI gives the surgeon
information about the
extent of the spread of
disease which can help
with choosing the
surgical approach.
1. Larson DM et al. Prognostic significance of gross myometrial invasion with endometrial cancer. Obstet Gynecol 1996
2. Sala E et al. MRI of malignant neoplasms of the uterine corpus and cervix. AJR Am J Roentgenol 2007
FIGO 2009: Management based on Stage
Stage
Description
IA
Tumor confined to uterus, <50% myometrial invasion
IB
Tumor confined to uterus, ≥50% myometrial invasion Surgery +/- vaginal brachytherapy
II
Cervical stromal invasion Surgery + vaginal brachytherapy +/- pelvic radiotherapy
IIIA
Tumor invasion into serosa or adnexa
IIIB
Vaginal or parametrial involvement
IIIC1
Pelvic node involvement
IIIC2
Para-aortic node involvement
IVA
Tumor invasion into bladder or bowel mucosa
IVB
Distant metastases
Surgery
Surgery + pelvic radiotherapy
+/- chemotherapy
+ Hormonal Rx
Modified from: Beddy et al. FIGO Staging System for Endometrial Cancer. RadioGraphics 2012
Appearance of Endometrial Cancer
T2
A
B
T2
 Tumor on T2-wt images
 Intermediate signal
intensity relative to the
hyperintense endometrial
lining
 Mildly hyperintense
relative to isointense
myometrial lining
*
GUCXM3
Figure: Sagittal T2-wt fat-saturated images in two patients with
endometrial cancer. In image A, there is diffuse intermediate signal
intensity thickening (
) of the endometrium. No normal
endometrium is identified. In image B, the intermediate signal
intensity tumor ( * ) is well-differentiated from the surrounding normal
hyperintense endometrium ( ). Note the disruption of the junctional
zone and extension into the myometrium inferiorly ( ).
Appearance of Tumor
T1-post
T2
 T1-pre contrast imaging
 Tumor isointense relative to
hypointense normal
endometrium on
unenhanced images
 Often difficult to discern on
pre- contrast imaging,
especially in small tumors
*
 T1-post contrast images
 Dynamic contrast enhanced
images are obtained
 Tumor enhances
homogenously and more
slowly with less avidity than
adjacent myometrium
 Endometrial tumors
enhance earlier than normal
endometrium
Figure: Sagittal T2-wt and T1-post contrast images in a 55 year old
female with endometrial cancer. The tumor demonstrates
intermediate T2 signal intensity (
) as well as hypoenhancement
(*) relative to the avidly enhancing myometrium ( ). Note the
irregular myometrial contour ( ) consistent with myometrial
invasion.
Appearance of Tumor
 Endometrial cancer demonstrates diffusion restriction compared to
surrounding tissue
 Diffusion weighted imaging (DWI)
 B=0, B=500 and ADC maps
 The tumor will become progressively brighter from B=0 to B=500
 On the ADC map, the tumor is dark relative to the endometrium and myometrium,
but can blend in with the junctional zone
T2
T1-post
GUCXM3 B=0
B=500
Figure: Sagittal T2-wt, T1-post-contrast and diffusion weighted images. The tumor appears
round, minimally hyperintense on T2-wt images (
), hypointense compared to avidly
enhancing myometrium on post contrast images (
), and on DWI (
) was gray on B=0,
bright on B=500 and dark on ADC map. In this case there is greater than 50% myometrial
invasion.
ADC
Appearance of Endometrial Cancer
 Depth of myometrial invasion is optimally
seen on T2-wt images and DWI images
Figure: (A) Sagittal T2-weighted image of the deepest extent of
myometrial invasion. Measure the depth of myometrial
invasion by drawing a line along the expected inner edge of the
myometrium. Then draw lines measuring the thickness of the
entire myometrium and the extent of tumor invasion in to the
myometrium. The ratio of the black line over the white line is
the percentage of MI. (B) B=0, B=500, and ADC map depicting
GUCXM3
the tumor. Use the DWI image to aid in your measurement and
help find the deepest extent of MI ( ).
B
A
T2
Stage IA
 Stage 1 tumors account for over 80% of cases
 Abnormal signal intensity on T2-wt images confined to the endometrium as
well as tumor that invades less than 50% of the myometrium
T2
T1-post
T2
T1-post
*
B=0
B=500
ADC
Figure: Sagittal T2-wt, T1-post contrast and diffusion
weighted images in a 68 y/o female with Stage IA
endometrial cancer. The abnormal signal intensity on
the T2-wt image is confined to the endometrium (
).
There is preservation of the junctional zone (
) and no
evidence of myometrial invasion. The mass restricts
diffusion (
) on the ADC map.
Figure: Sagittal T2-wt and T1-post contrast images
in a 64 y/o female with Stage IA endometrial cancer.
There is focal abnormal T2 signal intensity involving
the endometrium (*). There is disruption of the
junctional zone anteriorly and posteriorly in the
region of the body with less than 50% myometrial
invasion (
). No cervical invasion.
Stage IB
T2
T1-post
Figure: T2-wt and T1-post contrast images in a 59 year old female with Stage IB endometrial
cancer. The abnormal signal intensity on the T2-wt images involves greater than 50% of the
myometrium ( ). T1-post contrast images provide tumor to myometrium contrast and
demonstrates the hypoenhancement of the tumor ( ) relative to the adjacent
myometrium.
Stage II
T2
T1-post
 Direct invasion of the cervical
stroma
 Tumor demonstrates
intermediate to high signal
intensity on T2-wt images that
disrupts the normal low signal
intensity cervical stroma
GUCXM3
 Radical hysterectomy is
required for these patients as
opposed to total abdominal
hysterectomy in earlier stage
patients
 Lymphadenectomy is also
Figure: T2-wt and T1-post contrast images in a 51 year old
performed at many institutions
female with Stage II endometrial cancer. There is a lobulated T2
in these patients
hyperintense non-enhancing mass along the posterior uterine
wall in the lower uterine segment (
). The mass splays open
the endocervical canal ( ) and extends into the hypointense
cervical stroma ( ).
Stage III and IV
T2
 IIIA
 Invasion of uterine serosa or adnexa
 IIIB
 Invasion into upper vagina or parametrium
 IIIC-Enlarged regional lymph nodes
 IIIIC1-pelvic lymph node involvement
 IIIIC2-paraortic lymph node involvement
 IVA
 Bladder or rectal wall invasion
T1-post
 IVB
 Distant metastasis
 Lymphadenopathy above the renal vein,
malignant ascites or peritoneal carcinomatosis
 Imaging features of lymph node
metastasis







Size criteria > 1 cm in short axis diameter
Rounded or irregular contour
Multiplicity
Central necrosis
Diffusion restriction
Hypermetabolic activity on PET
However, metastasis can be present in normal
sized lymph nodes!
Figure: Axial T2-wt and T1-post contrast images in a
56 year old female with stage IIIC1 endometrial
cancer. There is an enlarged 1.5 cm rounded left
external iliac lymph node present ( ). Notice there
is an area of intermediate signal in the endometrial
canal on the T2-wt image (
), which is seen to
subtly enhance on the T1-post image (
).
Benign mimics of Endometrial Cancer
 Fibroid
 Adenomyosis
 Polyp
 Endometrial hyperplasia
GUCXM3
Fibroid
T2
T1-post
B=0
B=500
GUCXM3
Figure: Sagittal T2-wt, T1-post contrast and diffusion weighted images
demonstrating two large fibroids ( , ) , one of which is degenerating ( ).
Fibroids typically demonstrate low T1 and T2 signal and heterogeneous
enhancement; however, degenerating fibroids demonstrate increased T2 signal
intensity. Typical fibroids will be dark on B=0, B=500 and the ADC map.
Degenerating fibroids will be bright on the B=0 and B=500, having a variable
appearance on the ADC map .
ADC
Adenomyosis
T2
B=0
B=500
Figure: Sagittal T2-wt and diffusion weighted images in a 45 year old female with
adenomyosis ( ) and concurrent endometrial cancer ( ). Adenomyosis is defined as
the presence of heterotopic endometrial glands and stroma in the myometrium with
adjacent smooth muscle hyperplasia. MRI imaging features include diffuse widening of
the junctional zone with bright T2 foci within the junctional zone (corresponds to
heterotopic endometrial tissue); both of these findings are seen in this case. PITFALL: In
patients with coexistent endometrial cancer and adenomyosis, myometrial invasion is
often overestimated leading to staging errors. In this case, less than 50% myometrial
invasion was called on MRI and pathology demonstrated no myometrial invasion.
ADC
Polyp
T2
T1-post
B=0
B=500
GUCXM3
Figure: Sagittal T2-wt, T1-post contrast and diffusion weighted imaging in a 55 year
old female demonstrating a polyp in the endometrial canal ( ). Polyps can
demonstrate low T2 signal intensity secondary to the central fibrous core.
However polyps can also contain glandular secretions and cystic areas and
therefore can also demonstrate high T2 signal. Polyps enhance briskly and
sometimes have a “lace-like” appearance on the post-contrast images. When
polyps are dark on the T2-wt images, they are dark or isointense on B=0, B=500
and ADC map compared with endometrium. When polyps display high signal on
T2-weighted images, they will follow the endometrium on B=0, B=500 and ADC
map. PEARL: Diffusion weighted imaging is key, polyps won’t restrict diffusion
while endometrial cancer will.
ADC
Endometrial hyperplasia
T2
T1-post
B=0
B=500
GUCXM3
Figure: Same case! There is concurrent endometrial hyperplasia ( ) in the
canal. PEARL: The appearance of the tissue surrounding the polyp ( ) is T2
bright and is bright on B=0, B=500 and ADC map, typical of endometrial
hyperplasia. Endometrial hyperplasia does not restrict diffusion.
ADC
Same patient…keep looking
T2
B=0
GUCXM3
T1-post
B=500
Figure: Sagittal T2-wt, T1-post and diffusion weighted images again in the same
patient, now to the right of midline. The patient also has concurrent endometrial
cancer ( ). The round area within the fundus demonstrates T2 hyperintensity,
minimal enhancement, slight hypointensity compared to endometrium on B=0,
becomes bright on B=500, and is dark on the ADC map. This is consistent with
endometrial cancer. Adjacent hyperplastic endometrium is bright on B=0, B=500
and ADC ( ). This was proven on surgical pathology.
ADC
Concurrent endometrial cancer, hyperplasia and polyp
T2
T1-post
B=500
B=0
ADC
GUCXM3
Figure: Axial T2-wt, T1-post-contrast and diffusion weighted images depict all three
entities in one plane. Endometrial hyperplasia ( ) is hyperintense to myometrium on
T2-wt images and is bright on all DWI images and the ADC map. Endometrial cancer
( ) and the polyp ( ) are isointense to myometrium on the T2-wt images and
enhance on post contrast images. The endometrial cancer becomes brighter on the
B=500 image and darker on the ADC map. The endometrial polyp remains dark on all
DWI images and ADC map. These findings were confirmed on surgical pathology.
Summary
 MRI is excellent at depicting uterine anatomy and assessing
endometrial cancer.




Tumor size and extension
Myometrial invasion
Parametrial/cervical invasion
Lymphadenopathy
 Although currently endometrial cancer is staged surgically,
MRI does play a critical role in pre-operative planning.
 Differentiating endometrial cancer from co-existing
endometrial hyperplasia, adenomyosis, fibroids, and polyps is
important in the accurate assessment of endometrial cancer.
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