DIE – From darkness to light: Advances in Sonography Aids Diagnosis of Deep Infiltrating Endometriosis
Endometriosis is one of the most challenging gynaecological disorders, affecting 10 % of premenopausal women. Symptoms of endometriosis include dysmenorrhea, dyspareunia, dyschezia and infertility. One possible reason for major delay and misdiagnosis of this condition is the suboptimal primary assessment of patients with pelvic pain and suspected endometriosis.
By Dr Anjana Thottungal MBBS, MD, MRCOG,
FRANZCOG, DDU
Deep infiltrating endometriosis( DIE) is defined by the presence of endometrial implants, fibrosis and muscular hyperplasia below the peritoneum. The exact incidence of DIE is unknown, but it appears to be increasingly diagnosed. Commonly, it involves the uterosacral ligaments, the rectosigmoid colon, the vagina and the bladder. Intestinal endometriosis is one of the most severe forms of DIE.
Adequate primary assessment of patients with suspected DIE is particularly important as it not only reduces diagnostic delay but also enables clinicians to plan appropriate surgical treatment options, especially in cases of advanced and extensive disease. With a focus on the preoperative evaluation for DIE, several studies have evaluated the diagnostic value of magnetic resonance imaging( MRI).
However, MRI is time consuming and expensive. Recent evidence strongly suggests that transvaginal sonography( TVS) has an important role in detecting DIE of the pelvis, not only involving the ovaries but also the vagina, the rectovaginal septum, the uterosacral ligaments( USL), the bladder or the rectal wall. Higher diagnostic accuracy of TVS has led to the suggestion that TVS should be used as the first line of diagnostic imaging in suspected DIE.
Accurate preoperative diagnosis of intestinal endometriosis is also essential for informing women about the specific risks of surgery( e. g. colorectal resection). Rectosigmoid junction is the site of nearly twothirds of cases of intestinal endometriosis and is easily evaluated on TVS. Rectosigmoid endometriosis is almost always associated with USL involvement. Studies have shown that a simple rectal enema( Fleet enema) one hour before TVS permitted easy identification of the different bowel layers. Sonographic demonstration of utero-rectal adhesions, reflected by a negative uterine sliding sign, is an easy method for predicting the presence of DIE involving the rectum.
Following are the sonographic changes of pelvic structures associated with DIE:
�� ������������������������������������������������������������ structure or hypoechogenic linear thickening with regular / irregular margins near the cervical insertion( Fig. 1).
�� ���������������������������������������������������������������� or non- cystic nodularity within the posterior vaginal wall( Fig. 2).
�� ������������������������������������������������������������������ in the area between the rectum and the posterior vaginal wall from the level of introitus to the lower border of the posterior lip of the cervix( Fig. 3).
�� ���������������������������������������������������������������� � within the posterior wall of the urinary bladder.
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� Figure 1-Uterosacral nodule seen near the cervical insertion
� Figure 3-Hypoechoic lesion with cystic areas on the RV septum
the uterus and adnexae and rectosigmoid colon are fixed to each other with disappearance of the peritoneal structure. Obliteration is considered to be‘ incomplete’ when peritoneal limits are partially identified with the presence or absence of suspended or lateralised fluid collection.
� Figure 2-Hypoechoic cystic lesion in the vagina
� Figure 4-solid irregular nodule in the intestinal loop adherent to posterior wall of the uterus.
� Figure 5-Mid-sagittal view of the pelvis on Sonovaginography.
�� ���������������������������������������������������� mass distorting and replacing the normal appearance of the muscle layer of the rectal wall.
�� ���������������������������������������������������������������� involving the intestinal wall( Fig. 4).
It has been found that sonovaginography is a reliable and simple method for the assessment of rectovaginal endometriosis and provides information on location, extension and infiltration of the lesions, which are important factors in selecting the kind of surgery. Sonovaginography involves introducing sterile gel into the vagina that creates an acoustic window between the transvaginal probe and surrounding structures of the vagina( Fig. 5). An accurate mapping of the disease extension helps to define the multidisciplinary surgical team needed to manage the patient.
References on request. �
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