Hysterosonography (Saline Infusion Sonography)

What Is Hysterosonography?

Hysterosonography (Saline Infusion Sonohysterography – SIS) is a special diagnostic method that allows the uterine cavity and its lining (endometrium) to be examined in detail with ultrasonography. This procedure is performed by introducing sterile salt water (saline) into the uterus. This fluid expands the uterine cavity, allowing structural problems that are difficult to see on normal ultrasound — such as small polyps, myomas, or an intrauterine septum — to be visualized much more clearly.

Why Is Hysterosonography Performed?

Hysterosonography (SIS) is a minimally invasive imaging method developed to evaluate the inner cavity of the uterus. In the procedure, sterile physiological saline is introduced into the uterus with the help of a thin catheter, expanding the cavity. This fluid separates the uterine walls from one another, allowing the endometrium (the inner layer of the uterus) to be examined in much greater detail. During the procedure, a transvaginal ultrasound probe captures images, and the physician evaluates the internal structure of the uterus live on the screen.

Hysterosonography is a method that is less invasive than hysteroscopy and provides much more detailed information than standard ultrasound. The fact that it involves no radiation, uses no allergenic substances, and requires no general anesthesia makes the method safe and patient-friendly. It is also known to have a higher accuracy rate than HSG (hysterosalpingography) in detecting intrauterine pathologies.

The procedure generally takes 15 to 30 minutes. Most patients feel mild discomfort, and the great majority can return to their daily activities the same day. Prof. Dr. Melahat Atasever performs hysterosonography in Ankara at high resolution with modern transvaginal ultrasound devices.

What Is the Difference Between Hysterosonography and Standard Ultrasound?

While standard transvaginal ultrasound provides a general assessment by imaging from outside the uterus, in hysterosonography the fluid introduced into the uterus expands the cavity and clearly reveals the inner wall. Small endometrial polyps and thin intrauterine adhesions that standard ultrasound may miss can be clearly distinguished with hysterosonography.

Submucous myomas (myomas that grow toward the cavity rather than into the uterine muscle) can also be missed by standard ultrasound. In hysterosonography, the fluid makes the contours and dimensions of these structures distinct, providing information that directly influences the physician’s surgical decision. In summary, hysterosonography is the first-choice diagnostic tool for intrauterine pathologies where standard ultrasound falls short.

Why Is Hysterosonography Performed? Indications

The area in which hysterosonography is most frequently applied is infertility investigation. In women who cannot conceive, evaluating the anatomy of the uterine cavity directly shapes the treatment plan. Since the presence of submucous myomas or polyps must be known before IVF (in vitro fertilization), hysterosonography is part of the standard preliminary evaluation protocol. These structures can negatively affect embryo implantation and thereby adversely influence IVF outcomes.

In women with a history of recurrent miscarriage, hysterosonography is frequently preferred for investigating anatomical factors such as uterine septum, T-shaped uterus, or Asherman’s syndrome (intrauterine adhesions). This method is also used in cases of abnormal uterine bleeding unresponsive to treatment, in the detection of a thickened endometrium in the postmenopausal period, and when an IUD (intrauterine device) complication is suspected.

Hysterosonography is also used to map the anatomy of the uterus before hysteroscopy. It provides valuable guidance for the physician in determining which area to focus on and in preventing unnecessary surgical intervention.

Preparation Before Hysterosonography

For hysterosonography, it is recommended that the procedure be performed during a specific period of the menstrual cycle. The ideal time is the period from the end of menstruation until ovulation, that is, between the seventh and eleventh days of the cycle. Since the endometrium is thin during this period, the inner wall of the uterus and any possible lesions are visualized much more clearly.

Before the procedure, the presence of active pelvic inflammatory disease or vaginal infection is investigated; if an infection is detected, the procedure is postponed until antibiotic treatment is completed. In some clinics, prophylactic antibiotics are administered. The patient should inform the physician of any drug allergies, medications used, and previous gynecological surgeries. Taking a pain reliever before the procedure can reduce possible cramping.

Pregnancy is a contraindication for hysterosonography; therefore, a test is performed beforehand in women with suspected pregnancy. The procedure does not require anesthesia; a slightly full bladder can improve the image. Informing the clinic of the date of your last menstrual period when making the appointment makes it easier to plan the most suitable day.

How Is Hysterosonography Performed?

The procedure is carried out on a gynecological examination table under transvaginal ultrasound guidance. First, a speculum is placed in the vagina to make the cervix visible, and the cervical area is cleaned. A thin and flexible catheter of suitable size is placed into the uterine cavity through the cervical canal.

After the speculum is removed, the transvaginal ultrasound probe is placed in the vagina. Through the catheter, five to twenty milliliters of sterile physiological saline are slowly introduced into the uterus. The fluid separates the uterine walls from one another and expands the cavity. Meanwhile, the physician examines the endometrium in all aspects on the screen, detecting pathologies such as polyps, myomas, adhesions, or anatomical anomalies.

The procedure usually takes 15-25 minutes. Anesthesia is not required. During the fluid injection, mild discomfort similar to menstrual cramps may be felt; this is temporary. If 3D ultrasound support is available, the shape of the uterus and the geometry of the cavity can also be examined in three dimensions.

What Can Be Seen with Hysterosonography?

The main pathologies detectable with hysterosonography include endometrial polyps, submucous myomas, intrauterine adhesions (Asherman’s syndrome), uterine septum, and T-shaped uterus. Suspected endometrial hyperplasia can also be evaluated with this method. The location, size, and number of each pathology within the cavity are documented in detail.

During the procedure, it can also be assessed whether the fluid introduced passes from both fallopian tubes into the abdominal cavity; in this way, basic information about tubal patency is also obtained. However, for a detailed evaluation of the tubes, HSG (hysterosalpingography) or laparoscopy is required.

The Difference Between Hysterosonography and Hysteroscopy

Hysterosonography is a diagnostic tool; it has no therapeutic function. When a pathology is detected inside the uterus, the patient is referred to hysteroscopy if necessary. Hysteroscopy, on the other hand, is a more invasive method that involves inserting a thin camera into the uterus, providing both direct visualization and, in the same session, treatments such as polyp removal and adhesion cutting.

Since hysterosonography is less invasive and faster, it is preferred for the preliminary evaluation. If no pathology is detected, the patient is spared unnecessary exposure to an invasive procedure such as hysteroscopy. When a pathology is found, hysteroscopy comes into play for confirmation and treatment. Prof. Dr. Melahat Atasever applies both methods in line with clinical necessity.

The Process After Hysterosonography

After the procedure, mild watery discharge and spotting, which may last a few hours, are normal. Some patients may experience menstruation-like cramps; taking a pain reliever is soothing. Normal daily activities can be resumed the same day. Avoiding sexual intercourse and swimming pools for 24 hours is sufficient.

Hysterosonography findings are evaluated during the procedure; the physician conveys the results verbally within a short time. Depending on the pathology detected, hysteroscopy is planned for polyp removal, myomectomy, or treatment of Asherman’s syndrome. Prof. Dr. Melahat Atasever, in Ankara, shares treatment options transparently and supports a shared decision-making process.