What is Ultrasound Assessment of Tubal Patency (HyCoSy)?
The use of ultrasound to investigate tubal patency has become a well-established modality in parts of Europe and Britain and has led to the development of “1-stop shops” for the evaluation of infertility. The procedure has been called hysterosalpingo-contrast-sonography (HyCoSy).
What is done at HyCoSy?
Transvaginal ultrasound is used to evaluate tubal patency by passing a fine catheter into the cervix using a speculum. This part of the procedure does not differ from saline infusion sonography (sonohysterography). The cervix is then occluded by a balloon catheter (usually 1 mL balloon) so that the injected contrast agent is directed down the fallopian tubes. Transvaginal ultrasound is then used to assess flow of dye down the tubes to ensure they are not blocked. In most cases 10 – 20 mL of contrast agent is sufficient to assess the tubes.
Will the test hurt?
The procedure is generally well tolerated; it has been demonstrated to be less painful than X-Ray assessment of the tubes (HSG) in randomised studies and most patients report that it is no more painful than the pain they experience during their period. The pain usually resolves shortly after the procedure is finished. It is however more uncomfortable than a sonohysterography due to the balloon occlusion of the cervix and 2 tablets of naprogesic® ½ hr before the procedure should make the procedure less uncomfortable. Patient preparation is no different to transvaginal ultrasound (i.e. nil) but it is essential that the patient be seen in the proliferative phase of the cycle (just after a period) so as to avoid any possibility of pregnancy. The procedure takes ½ hour.
How Accurate is HyCoSy?
HyCoSy performs well against the traditional gold standard of laparoscopy and dye with sensitivities and specificities over 80% in most studies.
There are other techniques to assess tubal patency, which is best?
HyCoSy has clear advantages over X-Ray assessment of the tubes (HSG):
- HyCoSy provides all of the added diagnostic information of a transvaginal ultrasound (alleviating the need for both an X-Ray assessment of the tubes (HSG) and transvaginal ultrasound in the same patient).
- Some studies have found that HyCoSy is more accurate than HSG in diagnosing tubal patency
- it is less painful than HSG;
- it does not involve irradiation to the ovaries (unlike HSG);
- it uses a non-allergenic contrast agent unlike HSG.
HyCoSy will never completely replace laparoscopy and dye as a diagnostic technique because ultrasound cannot detect small areas of endometriosis or minor adhesions. HyCoSy has however been proposed as a first-line investigation, especially in patients where laparoscopy is not required for other reasons.
Are there any complications?
Complications are extremely rare after this procedure. Because a catheter has been inserted and contrast agent has been injected into the uterus, there is a theoretical risk of infection. Infection is however extremely rare after this procedure. To further minimise the risk of infection it is suggested that you not use a tampon for at least 24 hours after the procedure.