Keywords
bladder endometriosis - endometrioma - endometriosis - MRI - structured reporting
- ureteral endometriosis - uterine ligaments
Introduction
Endometriosis is the presence of functional endometrial tissue in ectopic locations,
that is, outside the uterine cavity, with an estimated prevalence of 5 to 10%.[1]
[2] The disease is estrogen-dependent, hence seen in the reproductive age group, with
a peak incidence between 24 and 29 years.[1] The terms endometriosis and endometriomas are often used interchangeably. Endometriosis
is a spectrum of diseases that include ovarian endometriomas, endometrial implants,
and adhesions in the pelvic peritoneum and retroperitoneum.[2]
Learning Objectives
This article will address the following:
-
Etiology and pathogenesis of endometriosis.
-
Optimal magnetic resonance imaging (MRI) protocol and technique for pelvic endometriosis.
-
Magnetic resonance (MR) signal characteristics and location of pelvic endometriosis.
-
Classification of endometriosis according to location in the pelvis and the imaging
appearance.
-
Structured reporting system.
Etiology and Pathogenesis
Etiology and Pathogenesis
There are numerous theories regarding the etiology of endometriosis, which is still
unclear. The most accepted theories are the metastatic, metaplastic, and induction
theories. Research is still on regarding other factors that may be responsible for
the development of endometriosis like growth factor and immunity.[2] Metastatic theory, which is the most widely accepted, states that implants in the
pelvic cavity are as a result of metastatic retrograde menstruation of viable endometrial
tissue into the pelvic cavity.[3]
[4] This theory is corroborated by the fact that the implants are seen in the dependent
portion of the pelvic cavity and are commonly seen when there is an obstruction of
antegrade menstrual flow in Mullerian anomalies ([Fig. 1]). The implants which are seen outside the pelvic cavity are believed to be due to
metastatic spread of the endometrial tissue via the lymphatics, bloodstream, or iatrogenic
spread postsurgery or biopsy.
Fig. 1 (A–C) T2W sag (A), FS T2W (B), and T1W (C) axial images showing a distended vagina filled
with hemorrhage due to outflow obstruction (arrow) along with right endometrioma (arrowhead in B and C). FS, fat-suppressed; T1W, T1-weighted; T2W, T2-weighted.
The metaplastic theory supports the differentiation of the remnant Mullerian tissue
or serosal surfaces into endometriotic cells. It suggests that the peritoneal cells
differentiate into functional endometrial tissue as the endometrial and peritoneal
cells are both derived from the coelomic epithelium. This is supported by the fact
that endometriosis is also seen in patients with Turner syndrome, gonadal dysgenesis,
and uterine agenesis that lack eutopic endometrium.[2]
[4]
The induction theory is a mixture of the metastatic and metaplastic theories which
states that the ectopic endometrium secretes tissues that initiate the differentiation.[2]
[4]
Classification of Endometriosis
Classification of Endometriosis
Endometriosis is a spectrum of diseases which consist of superficial, deep endometriosis
which can be peritoneal or extraperitoneal, ovarian endometriomas, and adhesions.
Superficial endometriosis (Sampson’s disease) is deposited on the surface of pelvic
organs or the peritoneum which can be hemorrhagic or nonhemorrhagic. The superficial
nonhemorrhagic implants are not visible on imaging and are seen only at laparoscopy.
They are seen as white, black, or red spots on laparoscopy depending on the degree
of scarring, fibrosis, and hemorrhage within the lesion. Deep infiltrating endometriosis
(DIE) by definition is a peritoneal implant extending into the retroperitoneum with
a depth of more than 5 mm, with a prevalence of approximately 1% in the reproductive
age group; 20% of women are affected by endometriosis.[4] It is the solid, infiltrating type, and is the major contributor to female infertility
and pelvic pain.
Diagnosis of Endometriosis
Diagnosis of Endometriosis
The presumptive diagnosis of endometriosis is made by imaging. Transvaginal (TVS)
and transrectal sonography (TRS) are the first-line imaging modality. TVS is able
to pick up implants of 1.5 cm or more. TRS is valuable for the evaluation of the rectosigmoid
and rectovaginal septum. It has higher sensitivity than MRI to evaluate the degree
of bowel wall infiltration.[4] The overall accuracy of TVS in the detection of DIE is similar to MRI but it requires
knowledgeable and experienced operators in interpreting the sliding sign to diagnose
adhesions.[5] MRI is the best imaging technique and provides a road map for surgeons of DIE. It
is able to pick up lesions hidden by adhesions both in the peritoneal and subperitoneal
space. It is performed as a second-line investigation after TVS in complex cases.
Definitive diagnosis is made by laparoscopy.
MRI Protocol
Our standard protocol is as per European Society of Urogenital Radiology guidelines.[6] Contrast images were acquired to better illustrate the rectal/ureteral deposits
as and when required.
All scans were performed on a 3.0 T scanner (Verio; Siemens, Erlangen, Germany). All
patients were scanned irrespective of the menstrual cycle with 4-hour fasting. The
patient was placed feet first on the spine coil with the phased array coil placed
on the pelvis and images were obtained from the pelvic inlet to 5 cm below the symphysis.
Intravenous (IV) Buscopan (scopolamine-N-butyl bromide) was administered on the table at the time of scanning to reduce bowel
peristalsis and uterine contraction.[5]
[6]
[7] No rectal enema was administered. Vaginal gel was given to delineate the fornices
in a few cases. Bladder should not be over-distended as that may result in detrusor
contractions resulting in image degradation and missing of small parietal nodules.[5]
[6]
[7]
Locations of Endometriosis
Locations of Endometriosis
The common locations of endometriosis are ovarian endometriomas, adhesions at the
base of the pouch of Douglas, vesicouterine space, rectovaginal septum, rectosigmoid,
urinary bladder, and anterior abdominal wall ([Fig. 2]).[3]
[4]
[5]
Fig. 2 The common sites of endometriotic deposits include anterior abdominal wall (a), ovaries
(b), vesicouterine septum (c), rectouterine septum (d), rectum (e), rectovaginal pouch
(f).
MRI Features of Ovarian Endometriomas
MRI Features of Ovarian Endometriomas
Endometriomas show high signal on T1 weighted (T1W) images and low signal on T2W images.
The characteristic findings include:
-
T2 shading effect: the supernatant displays high signal on T2W images and the dependent
portion shows low signal intensity (SI; [Fig. 3]).[4]
[5]
[6]
[7]
[8] This is attributed to the repeated cyclical hemorrhages and high concentrations
of methemoglobin, protein, and iron products in endometriomas, hence they are bright
on T1W images.
-
T2 dark spots: referred to low SI foci seen along the periphery of the endometriomas
due to chronic hemorrhage ([Fig. 4]).
-
T2 dark rim: a hypointense hemosiderin rim is seen around the ovary/endometrioma ([Fig. 5]).
-
Contrast enhancement–peripheral enhancement on IV contrast administration unlike hemorrhagic
cysts, which show no enhancement; however, this is not a specific finding.[2]
Fig. 3 (A, B) T2W (A) and FS T1W (B) axial images showing bilateral endometriomas with T2 shading
(arrow). FS, fat-suppressed; T1W, T1-weighted; T2W, T2-weighted.
Fig. 4 (A, B) T2W sag (A) and T2W FS axial (B) images showing hypointense nodular areas along
the periphery of the endometriomas (arrow)—“T2 dark spot.” Note is also made of a large deep endometriotic deposit in the posterior
uterine myometrium (arrowhead). FS, fat-suppressed; T2W, T2-weighted.
Fig. 5 T2W axial image showing the hemosiderin hypointense rim around the right ovary (arrow).
Differential Diagnosis of Ovarian Endometriomas
Differential Diagnosis of Ovarian Endometriomas
-
Functional hemorrhagic cyst (FHC): absence of T2 shading, dark spot, and hypointense
rim. Usually unilateral and shows no enhancement, unlike endometriomas which are usually
bilateral and multifocal. FHC usually disappears in the 4 to 6 weeks follow-up examination.
A study by Balaban et al reported significantly lower apparent diffusion coefficient
(ADC) values in endometriotic cysts compared to hemorrhagic cysts.[9]
-
Mature cystic teratoma: show suppression in signal on T1W fat-suppressed (FS) images.
-
Mucinous tumors: show hyperintense signal on T1W pre- and post-FS images but it is
lower than that seen in endometriomas.
-
Abscess: diffusion-weighted images (DWIs) cannot differentiate an endometrioma from
an abscess as both can restrict; however, endometriomas are bright on T1W FS images,
whereas abscesses show low SI ([Fig. 6]). Endometriomas have low SI in parts on ADC because of “T2 blackout effects.”
Fig. 6 (A, B) (A, top row): DWI, ADC, and FS T1W images in the axial plane showing an abscess
with restricted diffusion and peripheral T1W hyperintensity (arrow). (B, bottom row): DWI, ADC, and FS T1W images in the axial plane showing an endometrioma
with restricted diffusion and T1W hyperintensity (arrowhead). ADC, apparent diffusion coefficient; DWI, diffusion-weighted image; FS, fat-suppressed;
T1W, T1-weighted.
MRI Features of DIE
DIEs are commonly overlooked on MRI as they show low SI and are commonly located adjoining
normal low T2W SI structures. They are composed of ectopic endometrial glands and
stromal cells which induce a dense fibromuscular response. The ectopic endometrial
glands appear hyperintense on T2W images and the fibrosis appears low in SI on T2W
images ([Fig. 7]).[2] Depending upon the composition of the deposit, the signal will vary on T2W images.
If there is hemorrhage within these masses, they will be seen as hyperintense foci
on T1W images. Commonly the surrounding fibrosis and smooth muscle hypertrophy may
be so extensive that it minimizes the cyclical bleeding within the ectopic endometrial
glands and these deposits are seen as spiculated low SI masses. Intracystic blood
clots restrict on DWI. On IV contrast administration, the enhancement depends on the
degree of inflammatory reaction, glandular tissue, and fibrosis.[4] Adhesions are commonly seen in endometriosis and are composed of fibrotic tissue
containing collagen fibroblasts and macrophages, giving a very low signal on MRI.
They appear as spiculated strands arranged at confluent angles or with indirect evidence
such as abnormal angulations of pelvic organs such as uterus, rectosigmoid, and ovaries,
which may be adherent in the cul-de-sac. Hydrosalpinx and nondependent fluid collections
are other signs.[2]
[10]
Fig. 7 (A, B) T2W (A) and T1W (B) axial images showing a spiculated mass (short arrow) with internal hyperintense foci suggestive of ectopic endometrial tissue (long arrow) with surrounding hypointensity suggestive of fibrosis and smooth muscle hypertrophy
(arrowhead). T1W, T1-weighted; T2W, T2-weighted.
Classification of Deep Endometriosis According to Pelvic Location
Classification of Deep Endometriosis According to Pelvic Location
The pelvic cavity is divided into three compartments: anterior, middle, and posterior,
functionally and clinically ([Fig. 8A]).[11]
Fig. 8 (A, B) Sag T2W image (A) showing the anterior, middle, and posterior compartments and (B)
T2W sag image showing the prevesical space (arrowhead). Vesicouterine pouch (thin arrow) and the vesico-vaginal septum (solid arrow). T2W, T2-weighted.
Anterior Compartment
It is a virtual space located posterior to the symphysis pubis, with its posterior
margin being the anterior surface of the uterus and posterior wall of the bladder.
It consists of the urinary bladder, urethra, vesicouterine pouch, and vesicovaginal
septum ([Fig. 8B]). The vesicouterine pouch is also known as the anterior cul-de-sac, formed by the
reflection of the peritoneum between the dome of the bladder and the uterus. The vesicovaginal
septum is a fat-filled space between the bladder and vagina.
Bladder endometriosis is rare with a reported incidence of 20% of cases.[1] It is the most commonly involved organ in the urinary tract followed by ureter,
kidney, and urethra. It is often multifocal with the dome and the trigone most frequently
involved. It shows low SI on T2W images ([Fig. 9]). Foci of hemorrhage may or may not be seen. Depending on the degree of vesical
wall infiltration, it can be intrinsic or extrinsic type. The extrinsic variety is
confined to the serosal surface. As the extrinsic vesical endometriosis does not invade
the mucosa, MRI may show abnormalities but these are not picked up at cystoscopy.
The intrinsic type infiltrates the muscular layer and is seen as mural masses that
project into the lumen. These are seen on cystoscopy.
Fig. 9 (A, B) Cor (A) and sag (B) T2W images showing a deep extrinsic deposit on the bladder (arrow in B) with intact mucosa (arrowhead in A). Note that the ovaries are bilaterally normal (arrows in A). T2W, T2-weighted.
The ureters are extraperitoneal, posteromedial to the external iliac vessels, and
lateral to the uterosacral ligaments (USLs) in the paracervical space in the pelvis.
Ureteral endometriosis is rarely seen with a reported incidence of approximately 10
to 20% of cases.[1] It also is of the extrinsic and intrinsic variety, the most common being the extrinsic
which is seen as a dense hypointense signal on T2W images adjoining the ureters ([Fig. 10]).[12] It almost never extends above the pelvic brim. They may or may not be proximal dilatation
depending on the degree of fibrosis. Commonly an associated ipsilateral endometrioma
or a rectosigmoid nodule >3 cm is seen. Seracchioli et al[13] described two histological patterns of ureteral involvement: fibrotic pattern where
only fibrosis was seen on histopathology and endometriotic type characterized by endometrial
glands within the ureteral wall and in the periuterine tissues. They found hydroureteronephrosis
was significantly associated with the endometriotic pattern, whereas endometriosis
in the rectovaginal septum is associated with the fibrotic ureteral type.
Fig. 10 (A–C) Cor (A and B) and axial (C) T2W images showing left-sided hydronephrosis (arrow in A), hydroureter (B), and a spiculated mass encasing the left ureter (arrow in C). T2W, T2-weighted.
Middle Compartment
It consists of the uterus, fallopian tubes, ovaries, and broad ligament. The ovaries
are suspended by the mesovarium which is a double fold of the peritoneum. The broad
ligament are also peritoneal folds that suspend the uterus.
Ovarian endometriosis can be superficial implants with adhesions, micro intraovarian
endometriomas, or deep implants that have repeated cyclic hemorrhage resulting in
endometriomas, also commonly known as chocolate cysts due to its dirty brown contents
on laproscopy.[4] Apart from endometriomas, ovarian involvement may also be seen in the form of adhesions.
The ovaries are seen pulled posteriorly and are seen adherent to the posterior margin
of the uterus also called kissing ovaries ([Fig. 11]). A sudden increase in the size of endometriomas with nodularity along the walls
which show restricted diffusion along with thick enhancing septations suggests malignant
change. Clear cell carcinoma and endometrioid carcinomas are associated with endometriosis
([Fig. 12]).[14]
Fig. 11 (A, B) T2W sag (A) and axial (B) images showing adherent ovary to the posterior surface
of the uterus (arrow in A) and both ovaries puckered posteriorly and to the midline (arrows in B)—kissing ovaries sign. T2W, T2-weighted.
Fig. 12 (A–D) T2W sag (A), cor (B), and T1W axial images without and with FS (C and D), showing
an endometrioma (arrows in C and D) with absence of T2W shading and a solid mural nodule (arrows in A and B) suggestive of malignant transformation. FS, fat-suppressed; T1W, T1-weighted;
T2W, T2-weighted.
Uterus-DIE of the uterine serosa is seen as low SI on T2W images with small cystic
areas. Involvement of the uterus can mimic adenomyosis. The differentiating factor
is that the junctional zone appears normal in thickness in invasive endometriosis
of the uterus; however, it shows widening more than 12 mm in adenomyosis ([Fig. 13]).[5]
[15] DIE is an “outside-in” process that spares the uterine junctional zone and should
not be misdiagnosed as adenomyosis. Adenomyosis in contrast is a process that is an
“inside-out process.” It is due to the abnormalities that arise from the interface
between the endometrium and the subadjacent myometrium as well as due to the presence
of ectopic endometrial and stromal tissue outside the endometrial complex but within
the uterus.
Fig. 13 (A, B) T2W sag images (A) showing widening of the junctional zone with diffuse adenomyosis
(arrow) and in panel (B) there is a deposit in the posterior serosal surface of the uterus
(arrow) with normal thickness of the junctional zone (short arrow). T2W, T2-weighted.
Cervix and vagina: the sensitivity and specificity of MRI for the diagnosis of involvement
of the cervix and vagina is 82%. The posterior vaginal fornix is the deepest part
of the vagina which is located posterior to the uterine cervix and is the most commonly
affected site as it is the most dependent part of the pelvis. Vaginal involvement
can be nodular or polypoidal. They are seen as T2W hypointense lesions with cystic
internal appearance. These cystic areas normally show T1W hyperintensity ([Fig. 14]). The polypoidal lesions display a T2W hypointense rim due to fibrosis.[9]
[16]
Fig. 14 (A–E) T2W sag image (A) showing a cystic deposit in the posterior cervical lip and extending
into the posterior fornix (arrow). T2W axial (B–D), T1W FS axial (C–E), showing similar deposits in the cervix (arrows in B and C) and vagina (D and E). Note is also made of a large deep endometriotic
deposit in the posterior uterine myometrium (arrowhead). T2W, T2-weighted.
Tubal involvement is also commonly seen in endometriosis. Hematosalpinx should be
considered specific for pelvic endometriosis.[4]
[17]
[18]
[19] The classical T2 shading seen in endometriomas is not often seen in the case of
hematosalpinx that occurs in association with endometriosis ([Fig. 15]). This is attributed to the deposit occurring over the surface of the fallopian
tubes opposed to the implants within the tubes. Peritubal adhesions and subsequent
tubal obstruction occur due to recurrent hemorrhage within the serosal implants.[4]
[18]
Fig. 15 (A–C) T2W (A), T1W (B), and FS T1W (C) images showing a dilated fallopian tube with hemorrhage
within it (arrows). FS, fat-suppressed; T1W, T1-weighted; T2W, T2-weighted.
Uterine ligaments: MR has reported sensitivity of 69% and specificity of more than
90% for diagnosis of implants in the USL.[4]
[5]
[19] They are best visualized on T2W images perpendicular to the cervix (discussed in
the posterior compartment). The round ligament is more commonly involved on the right
side. The explanation for this is the presence of the sigmoid colon which prevents
retrograde implantation on the left side. The implants on the ligaments are seen as
areas of T2W hypointensity. The ligaments may appear nodular, show significant hypointense
signal on T2W images, and measure more than 1 cm ([Fig. 16]).[4]
[5]
[18] Involvement of the extraperitoneal part of the round ligament is seen (canal of
Nuck) as a focal round hypointense mass on T2W images.[20]
Fig. 16 (A, B) T2W (A) and T1W (B) axial images showing a normal thread-like round ligament on
the left side (arrowhead) and a thickened ligament on the right side (arrow). T1W, T1-weighted; T2W, T2-weighted.
Posterior Compartment
It is a virtual space which is located between the posterior vaginal wall and the
anterior rectal wall. It consists of the rectovaginal pouch, rectocervical space,
the rectovaginal septum, the uterine torus, as well as the rectosigmoid ([Fig. 17]).
Fig. 17 (A, B) T2W sag images showing the recto-vaginal pouch (arrow in A), the recto-vaginal septum (arrowhead in A), and the retrocervical space (arrow in B). T2W, T2-weighted.
The rectocervical space is also a virtual extraperitoneal space. It is seen behind
the cervix in the same plane as the rectovaginal pouch and above the rectovaginal
septum.[4]
[5]
[11] It is a common site of deep endometrial deposit and is often associated with the
involvement of the USL.
The rectovaginal septum is located between the posterior vaginal wall and the anterior
rectal wall and extends from the deepest part of the pouch of Douglas to the perineal
body.[4] Its involvement is of three types according to the location: in the septum (10%),
posterior fornix of the vagina (65%), and hour glass-shaped lesion invoking the posterior
fornix with extension into the anterior rectal wall (25%).[21]
The pouch of Douglas also called the rectovaginal pouch is part of the peritoneal
cavity and it is a deep pouch situated between the rectouterine folds. It is the most
inferior part of the peritoneal cavity and is seen to cover part of the vagina and
rectum. It extends to the middle third of the vagina and is difficult to delineate
on MRI in the absence of peritoneal fluid ([Fig. 18A]).[4]
Fig. 18 (A–C) T2W sag (A) image showing a deep deposit on the serosal surface of the uterus extending
into the wall of the rectosigmoid (arrow). Oblique T2W axial image showing an endometriotic deposit in the wall of the rectosigmoid
with intact mucosa—mushroom sign (arrow). T1W FS axial image (arrow in C) showing foci of hyperintensity consistent with endometriosis. T1W, T1-weighted;
T2W, T2-weighted.
The rectosigmoid is the most commonly affected site, followed by appendix, terminal
ileum, cecum, and descending colon.[1] Rectosigmoid involvement commonly presents with cyclical hematochezia, constipation,
pencil-like stools, and episodes of intestinal subocclusion.[22] The involvement of the rectosigmoid has been described as a “mushroom cap sign”
([Fig. 18]).[22] It is considered a specific finding of solid invasive endometriosis of the rectosigmoid.
It is seen as a T2W hypointense lesion involving the serosal surface of the rectum
with sparing of the mucosal surface. The low signal intensity base of the mushroom
is due to hypertrophy and fibrosis of the muscularis propria, whereas the high signal
intensity cap represents the submucosa. The sensitivity of MRI to predict invasion
of the muscular propria is 100% and specificity is 75%.[19] It is limited in diagnosing submucosal involvement as edema and endometrial infiltration
of the submucosa cannot be differentiated.
Uterine torus is a ridge on the posterior aspect of the cervix where the USLs attach.
USL is seen as the in hypointense thread-like bands extending from the uterine torus
to the sacrum ([Fig. 19A]). Involvement of the USL is seen as thickening and nodularity of the ligaments with
foci of hemorrhage within them ([Fig. 19B]). The involvement of the uterine torus and USLs results in acute retroversion of
the uterus or anterior retraction of the rectum due to adhesions.[23]
Fig. 19 (A, B) T2W oblique axial image (A) showing the normal uterosacral ligaments (arrows) and the thickened ligament on the right side with cystic areas within it (arrow in B). T2W, T2-weighted.
Anterior Abdominal Wall
Scar endometriosis occurs as a result of the direct implant of functional endometrial
tissue into the anterior abdominal wall during pelvic surgery with a reported incidence
of 15 to 44%.[24] It can be cystic, mixed, or solid type. The imaging features depend on the phase
of the patient’s menstrual cycle, the chronicity, the degree of fibrosis, amount of
bleeding, and associated inflammation ([Fig. 20]).[25] The most common differential diagnosis includes a desmoid tumor. The other differentials
include a primary tumor of the muscle, suture granuloma, and lymphoma. The presence
of subacute hemorrhage in the endometriotic crypts seen as blooming on gradient images
and hyperintensity on T1W images helps differentiate scar endometriosis from other
lesions.[25]
Fig. 20 (A–C) T2W sag (A), T1W (B), and gradient (C) axial images showing a spiculated mass in
the anterior abdominal wall, involving the rectus abdominis muscle. It shows low SI
on T1W and T2W images (arrows in A and B) and blooming on the gradient images (arrow in C), suggestive of blood products. SI, signal intensity; T1W, T1-weighted; T2W,
T2-weighted.
Structured Reporting
Structured MRI (SMR) reports are essential to give clear and comprehensive information
to the physician, which can help in treatment planning. The reports should be organized
according to the anterior, middle, and posterior compartments which are not true anatomical
spaces but mirror the surgeon’s approach to treatment and also provide a logical and
organized search pattern for the radiologist. [Table 1] provides a detailed checklist that the radiologists can refer to while reporting
so as to not overlook or miss any lesion.[26]
Table 1
Structured MRI reporting
|
Anterior compartment
|
|
Lesion size
|
Location
|
Distance from UVJ
|
Hydronephrosis
|
|
Abbreviation: UVJ, ureterovesical junction.
|
|
Bladder
|
If present the size in minimum 2 dimensions
|
Intrinsic/extrinsic
|
Involved/not involved
|
Present/absent
|
|
Ureters
|
If present the size in minimum 2 dimensions
|
Intrinsic/extrinsic
|
In mm/cm
|
Present/absent
|
|
Vesicouterine space
|
If present the size in minimum 2 dimensions
|
|
|
|
|
Vesicovaginal space
|
If present the size in minimum 2 dimensions
|
|
|
|
|
Prevesical space
|
If present the size in minimum 2 dimensions
|
|
|
|
|
Middle compartment
|
|
Ovaries
|
Size of ovaries
|
Presence of follicles
|
Endometriomas: present/absent
Size in three planes
|
Presence/absence of adhesions
Relation to adjoining structures
|
|
Fallopian tubes
|
If dilated then size
|
Dilated/nondilated
|
Hydrosalpinx/hematosalpinx: present/absent
|
Presence/absence of adhesions
Relation to adjoining structures
|
|
Ligaments
|
If thickened then length of involvement
|
|
|
Presence/absence of adhesions
Relation to adjoining structures
|
|
Uterus
|
Size of uterus Anteverted/retroverted Endometrial thickness Junctional zone thickness
|
|
Lesion: present/absent Size, location and depth
|
Presence/absence of adhesions
Relation to adjoining structures
|
|
Cervix
|
|
|
Lesion: present/absent Size, location and depth
|
|
|
Vagina
|
|
|
Lesion: present/absent Size, location and depth
|
|
|
Posterior compartment
|
|
Involved/ not involved
|
Size
|
Adjoining structures
|
|
Rectocervical space
|
Yes/no
|
If present the size in minimum 2 dimensions
|
Adhesions, structures involved
|
|
Anterior rectal wall
|
Yes/no
|
If present the size in minimum 2 dimensions
|
Circumferential/focal, adhesions, structures involved
Muscular layer: invasion present/absent
Distance from anal verge
|
|
Uterosacral ligament
|
Yes/no
|
Length of involvement
|
Nodularity/diffuse involvement
Adhesions, structures involved
|
|
Rectovaginal space/septum
|
Yes/no
|
If present the size in minimum 2 dimensions
|
Adhesions, structures involved
|
|
Other locations
|
|
Sigmoid
|
If present then describe length, size, depth of invasion, and location
|
|
Appendix
|
If present describe size and location
|
|
Abdominal wall
|
If present then describe size and location
|
|
Nerves
|
If involved then describe size and location
|
Conclusion
Endometriosis is a complex benign disease process with varied presentations. It rarely
undergoes malignant transformation. Radiologists should be aware of the range of presentations
which vary depending on the acuity or chronicity of presentation and the degree of
fibrosis. Ultrasonography remains the primary imaging modality, followed by MRI in
complex cases. MRI has now emerged as the imaging of choice for deep endometriosis
and provides a road map to the surgeon. A SMR helps to organize and standardize reports,
and provides essential and precise information to the surgeon.
