Hysterosonography, some doctors refer to it as a Sonohysterogram, is another way of performing a pelvic ultrasound.  The essence of the study is that sterile saline distending the endometrial cavity significantly improves the clarity of transvaginal ultrasound assessment of endometrial abnormalities.  Often, conventional pelvic ultrasound (even with transvaginal scanning) will demonstrate an abnormally thickened endometrial stripe, but will not elucidate the exact etiology of the thickening.  The list of considerations include endometrial hyperplasia (in which the endometrial is uniformly thickened), endometrial polyp(s), endometrial malignancy, and submucosal fibroids (fibroids that protrude into the endometrial cavity).  The distinction is extremely important to properly treat the cause of a woman's abnormal vaginal bleeding. 

In hysterosonography, the perineum is prepped in a sterile fashion and a speculum examination is performed to localize the cervix (identical to a conventional internal examination by a gynecologist).  A betadine prep is then used on the cervix.  Thereafter, a thin relatively soft catheter is placed through the endocervical canal into the endometrial cavity.  A small retention balloon is inflated at the end of the catheter to hold it in place and the speculum is removed.  A transvaginal ultrasound is then performed while sterile saline is injected through the catheter.  The study is excellent for evaluating the endometrium of the uterus and has very few risks.  Some women may experience cramping during and after the procedure which is usually alleviated with indomethacin. 

The most common technical problem is inability to pass the catheter through the cervix.  Some hysterosonography kits come with a dilator that helps but often does not solve the problem.  The cervix in some women may function well to allow passage of blood and other materials from the uterus into the vagina.  However, the cervix of these same women may be too narrow to pass the catheter in the opposite direction.  Formal dilation of the cervix (such as performed by gynecologists for D & C's or hysteroscopy) may be necessary in some cases (which requires appropriate facilities in case of light anesthesia to be performed on an outpatient basis).  –  Scott Wise, M.D. 

Note:  The doctor may give the patient instructions to take 3 Advil’s (or one of its relatives) 1 hour before the procedure to alleviate cramping.  The hysterosonography procedure requires an empty bladder.   It is preferable for the procedure to be performed when the patient doesn’t have her menses.