Type:
Educational Exhibit
Keywords:
Pelvic floor dysfunction, Education and training, Imaging sequences, Education, Ultrasound, MR, Urinary Tract / Bladder, Gastrointestinal tract, Genital / Reproductive system female
Authors:
C. Walker, C. A. Johnson; Oxford/UK
DOI:
10.26044/ecr2019/C-2251
Background
Endometriosis occurs when functional ectopic endometrial tissue is found elsewhere in the body,
usually in the pelvis around the uterus,
ovaries and fallopian tubes. The ectopic tissue is sensitive to hormones and leads to bleeding,
inflammation and fibrosis and longer term sequelae.
It is a common cause of pelvic pain and infertility and affects as many as 10% of premenopausal women,
with potential devastating effects (1).
It takes,
on average,
7.5 years for a woman to be diagnosed with endometriosis (2).
Radiologists should be familiar with various imaging manifestations of disease and its appearances at different stages within this process to allow its differentiation from other pelvic lesions.
There are several theories regarding the pathogensis of endometriosis.
Retrograde menstruation with metastatic implantation of endometrial glands and stroma was intially suggested as the cause of disease by Sampson in 1927 and remains the most common theory,
however,
this is not always necessary to develop endometriosis. Several processes occur with migration of endometrial stroma from the uterus and successful attachment of these cells into the peritoneum and serosal surfaces (1,
2).
Imaging is used to diagnose and evaluate endometriosis.
Ultrasound and MRI are the modalities of choice but the disease or sequelae may also be seen on CT and fluoroscopic imaging.
Although endometriosis is a benign condition,
the effects of the disease can be malignant.
The disease causes local inflammation which is a key factor in adhesion formation.
This occurs as a result of endometrial implants bleeding onto the area around them,
causing inflammation followed by scar formation as part of the healing process.
When scar tissue comes into contact with an adjacent inflamed area it forms bands of tissue or adhesions.
Laparoscopically,
these can vary in appearance from thin and transparent to thick and opaque bands.
Thin adhesions are frequently missed on MR imaging.
In some cases,
adhesions can cause a matted or 'frozen' pelvis.