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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