Saline Infused Sonogram
Saline infused sonogram or SIS is used to specifically evaluate the uterine cavity. Normally, the inside of the uterus is lined by endometrium and is only a potential space. Because the upper and lower portions of the lining are adjacent to each other, the ultrasound cannot clearly distinguish between the two. Because of this, polyps and intracavity fibroids which distort the lining may be missed. Injecting saline into the cavity expands it and provides a contrast for the ultrasound which enables better visualization of the lining and the cavity.
The procedure begins with a regular ultrasound using the vaginal ultrasound probe for a preliminary view. Next, the doctor inserts a small catheter through the cervix and a pea-sized balloon is blown up, which keeps it in the uterine cavity. Your doctor gradually infuses the saline while the uterus is being observed by ultrasound. The results are interpreted immediately while the ultrasound is observed simultaneously by the ultrasound technician, your doctor and you.