Tubal Patency Assessment
The Fallopian tubes are tubes that guide the egg from the ovary to the uterus. To obtain a pregnancy, the Fallopian tubes must be open or patent. Tubal assessment may be recommended in some women who are having difficulty conceiving. Normal Fallopian tubes can not be seen on a regular ultrasound but a contrast medium can be used to demonstrate the Fallopian tubes.
THE CONTRAST MEDIUM
At Camberwell Ultrasound for Women the contrast medium used is Ex Em Foam.
A vaginal ultrasound is performed first to assess the pelvic anatomy.
If there is proof of ovulation in the current cycle, the tubal assessment is postponed to the next cycle. If the ultrasound shows an abnormality that needs assessment by the referring doctor first, the procedure may not be performed. If the ultrasound findings are normal and consistent with the first half of the cycle, tubal assessment is performed.
The vagina is disinfected with an antiseptic solution.
A speculum is placed in the vagina like for a PAP smear and the cervix is visualised.
A special catheter with a small 'pea' size balloon at the tip is inserted through the cervix.
Once the tip of the catheter is in the uterine cavity, the balloon is inflated with a tiny amount of saline (salt water). This helps keep the catheter in place. Dilatation of the uterine cavity associated with inflation of the balloon may cause some pain due to cramping of the uterus.
Once the balloon is correctly positioned in the uterine cavity, the speculum is removed and the vaginal probe is inserted in the vagina.
First a small amount of saline (salt water) is injected through the catheter. The saline allows accurate assessment of the uterine cavity since it outlines the lining of the uterus well.
The contrast is then prepared and injected through the catheter and the tubes are examined. Contrast should be seen flowing through the Fallopian tube and spilling around the ovary on both sides.
When spilling is seen on both sides, it can be concluded that the Fallopian tubes are patent. When the Fallopian tubes can not be seen, it can not always be concluded that they are blocked as spasm of the uterus can temporarily occlude the opening of the Fallopian tubes. In that case, the referring doctor will organise further tubal assessment.