Benefits of Sonohysterography
The use of fluid instillation into the uterus coupled with high resolution endovaginal probes can allow tremendous diagnostic enhancement with an inexpensive, simple, well-tolerated office procedure. Initially, sonography was a tool of the Obstetrician. High resolution endovaginal probes have revolutionized its use in Gynecology. They provide a degree of image magnification that is if we are doing ultrasound through a low powered microscope (sonomicroscopy). Structures that would not be appreciated with the naked eye can be discerned. Numerous attempts have been made to apply ultrasound to patients with abnormal uterine bleeding. If organic pathology is absent the bleeding in such patients is either anovulatory dysfunctional uterine bleeding (premenopausal) or atrophic (menopausal). Such studies have lent themselves to allow avoiding invasive biopsy or hysteroscopy or D&C in postmenopausal patients with abnormal bleeding when the ultrasound assessment of endometrial thickness and texture are suggestive of a lack of significant tissue (< 4-5 mm).
However in many patients we cannot reliably image the endometrial contents so as to exclude the presence of pathology. Instillation of fluid into the endometrial cavity through a small catheter allows exquisite delineation of intracavitary contents.
If patients are having cyclical bleeding (premenopausal or postmenopausal on sequential hormone replacement therapy) the technique should be performed as soon as possible after the bleeding episode ends, when the endometrium will be as thin as one expects it to be all month long. In postmenopausal women on no homone replacement therapy or on continuous combined HRT, timing of the procedure is not critical. If a baseline endovaginal ultrasound reveals a thin, distinct endometrial echo < 4-5mm, with an intact hypoechoic junctional zone surrounding it then no further evaluation is necessary. If the endometrial echo is > 4 - 5 mm or not well visualized (obesity, previous surgery, increasing parity, co-existing fibroids, etc.) then one proceeds to sonohysterography.
After determining the type and amount of uterine version (with sonography or bimanual exam) a speculum is inserted into the vaginal. The cervis is cleansed with an antiseptic solution. The Goldstein catheter is then inserted until the black mark at 7 cm is at the level of the external Os. Insertion is best performed by grasping the end of the catheter with a ring forceps and gently feeding it through the cervical Os. Sterile saline has been flushed through the catheter to rid it of small amount of air which when first injected can cause a very echogenic artifactual appearance. Once the catheter is in place its distal end is held firm and using the ring forceps the white acorn is advanced to external cervical Os. Note the seal will not be water tight. A water tight seal produces better images but will definitely result in a painful cramping sensation during the procedure. The purpose of the acorn is to retard, not eliminate run-back of fluid during instillation. This allows the procedure to be done with extreme comfort while still yielding diagnostic quality images. In those cases where the patient may be nulliparous or has a very small opening to her os, the acorn will not be necessary and in fact may obscure visualization in some patients. In these cases the acorn may simply be removed and discarded and the catheter used without it. The speculum is then removed carefully so as not to dislodge the catheter. Vaginal probe is then reinserted. Sterile saline is then infused through the catheter under real time ultrasound observation. It is important to scan in a long axis projection from side to side, i.e., from cornua to cornua. The amount of fluid instilled will be variable and depends on the image that one is producing on the ultrasound screen. When the uterus has been completely surveyed from cornua to cornua in a long axis projection the transducer is then rotated 90o into a coronal plane and further fluid is instilled while fanning down towards endocervical canal and up towards uterine fundus. In this way we recreate three dimensional anatomy taking great care not to miss any portion of the uterine cavity since some polyps or hyperplasia/carcinomas my be focal. Hard copy images are obtained. Appropriate measurements are performed and a description of the sonographic findings is made.
Analgesia or anesthesia is not required. The Goldstein catheter is 1.8 mm in diameter and is remarkably painless in its insertion. The procedure is remarkably well tolerated in the overwhelming majority of patients and minimal discomfort in a very small minority. With regards to infection, this procedure should be handled similarly to traditional hysterosalpingography. Thus the decision about whether to obtain cultures or the use of antibiotics will depend very much on the patient population you normally deal with.
©2004 Steven R. Goldstein, M.D.
