Saline infusion sonohysterography refers to a procedure in which fluid is instilled into the uterine cavity transcervically to provide enhanced endometrial visualization during transvaginal ultrasound examination [1,2]. The technique improves sonographic detection of endometrial pathology, such as polyps, hyperplasia, cancer, leiomyomas, and adhesions. In addition, it can help avoid invasive diagnostic procedures in some patients as well as optimize the preoperative triage process for those women who require therapeutic intervention. It is easily and rapidly performed at minimal cost, well-tolerated by patients, and is virtually devoid of complications. The American College of Obstetricians and Gynecologists, in conjunction with the American College of Radiology and the American Institute of Ultrasound in Medicine, developed a technology assessment document for saline infusion sonohysterography [3,4].
There are a number of situations where fluid enhanced endovaginal scanning will aid evaluation of the uterine cavity. The American Institute for Ultrasound in Medicine's standard indications and contraindications to this procedure are shown in the table (table 1).
Unscheduled uterine bleeding — Unexpected uterine bleeding accounts for a large proportion of gynecologic patient visits. Endometrial biopsy and/or office hysteroscopy are often used as initial diagnostic procedures; in hospital dilation and curettage is no longer considered an appropriate initial diagnostic test in most women .
Transvaginal ultrasound is used increasingly as an initial triage for patients with abnormal uterine bleeding. Sonohysterography is a subset of transvaginal sonography that is used when it is difficult to visualize the endometrium or the endometrium is thickened.
Sonohysterography is particularly useful for finding focal endometrial abnormalities or confirming that a focal abnormality diagnosed by transabdominal or transvaginal ultrasound is present and better defining the nature of the abnormality [6,7]. As an example, one study performed both transvaginal ultrasonographic examination and sonohysterography on 106 patients with menometrorrhagia . The sensitivity and specificity of saline infusion sonohysterography for detection of polyps were significantly higher than for transvaginal ultrasound alone (93 and 94 versus 75 and 76 percent for TVS) and were comparable to hysteroscopy, a finding confirmed by others [9-12].