PELVIC ULTRASOUND (TRANSVAGINAL ULTRASOUND)
Transvaginal ultrasound (TVS) is routinely used in the initial evaluation of the infertile patient and provides information about tubo-ovarian pathology (i.e. ovarian cyst, endometrioma, large hydrosalpinx) and uterine pathology (i.e. fibroids, endometrial polyps, and uterine anomalies). Advantages of TVS are that it is a simple tool with almost no infection risk, generally well tolerated, radiation-free method which provides information on the size and position of the uterus, and tubo-ovarian pathology. The disadvantages of TVS are its limited sensitivity and specificity in diagnosing abnormalities of the endometrial cavity and tubal pathology such as tubal blockage (i.e. hydrosalpinx).
FLUID ULTRASOUND (HYDROSONOGRAPHY)
Hydrosonography (fluid ultrasound) involves fluid injection (normal saline – salt water) into the endometrial cavity and simultaneous transvaginal sonography to visualize the endometrial cavity. Hydrosonography provides information about the pathological lesions in the endometrial cavity (i.e. myomas, polyps, adhesions, and congenital anomalies) as well as limited information on tubal patency. Fluid in the cul-de-sac during the procedure suggests tubal patency, but whether one or both tubes are patent cannot be determined. For intracavitary lesions it has the sensitivity and specificity almost comparable to hysteroscopy (gold standard), except intrauterine adhesions which may be better evaluated by hysteroscopy and treated during the same procedure.
Advantages of hydrosonography include low infection risk, easy tolerability and the lack of need for anesthesia. Disadvantages are the lack of comprehensive evaluation of fallopian tubes and the need for a second procedure such as hysteroscopy if an intracavitary lesion is suspected. If good distention is not accomplished with fluid ultrasound, endometrial cavity may not be fully assessed and a hysteroscopy in such cases is a better option.