Vaginal ultrasonography (synonyms: transvaginal ultrasonography, vaginal ultrasound, vaginal echography) is a diagnostic imaging procedure used in gynecology and obstetrics – to visualize the uterus (womb), ovaries (ovaries), uterine tuba (fallopian tubes), Douglas space (lat. Excavatio rectouterina or Excavatio rectogenitalis; this is a pocket-shaped protrusion of the peritoneum between the rectum (rectum) and uterus (uterus) that extends to the posterior vaginal vault), the urinary bladder and the urethra (urethra) – in which the ultrasound probe is inserted transvaginally (through the vagina). Examination of the pelvic organs using vaginal ultrasonography is a standard diagnostic procedure for all gynecological conditions. As part of cancer screening, it is used for early detection of tumors of the uterus (womb), fallopian tubes (tubes) and ovaries (ovaries). Sonographic examination offers the possibility of achieving a high-resolution image of the organs of the small pelvis and is a more accurate procedure than transabdominal sonography. Thus, vaginal sonography represents an accurate, painless, and low-risk method.
Indications (areas of application)
- Uterine malformations (malformations of the uterus).
- Carcinoma of the cervix uteri (cancer of the cervix).
- Benign tumors of the uterus (womb) such as fibroids (muscular growths).
- Benign or malignant changes of the endometrium.
- Ovarian cysts (ovarian cysts)
- Ovarian carcinomas (ovarian cancer; ovarian cancer screening).
- Tubal changes (changes in the fallopian tube) such as saktosalpinx, hematosalpinx.
- Carcinomas of the uterine tube (fallopian tube cancer).
- Descensus uteri (uterine prolapse).
- Topographical (location) changes of the urinary bladder and urethra (urethral) in descensus (prolapse) and urinary incontinence (bladder weakness).
- Determination of bladder capacity, residual urine volume; bladder wall thickness; tumors and foreign bodies in the bladder.
The procedure
The principle of vaginal ultrasonography is the emission of ultrasound waves via crystal elements in the ultrasound probe, which are reflected and scattered by the tissue structures of the organs to be examined. Due to the reflection from the tissue structures in the pelvis, the ultrasound waves are partially received by the crystal elements located in the ultrasound probe. Only specially shaped ultrasound heads are used for vaginal sonography. To the procedure of vaginal sonography:
- The sonographic examination does not require any preparatory measures, except that the sonography should be performed when the bladder is empty. During vaginal ultrasound, the patient lies on the gynecological examination chair.
- The attending gynecologist covers the ultrasound probe with a condom-like rubber cover containing a special gel to prevent the formation of air spaces to reduce the impedance phenomenon. Impedance represents a phenomenon that is of concern in the propagation of all sound waves and describes the resistance that opposes the propagation of ultrasound waves. Possible air pockets between the ultrasound probe and the tissue surface increase the characteristic impedance, thus reducing the resolving power of the procedure and lowering the diagnostic significance.
- The use of the cover with the included contact gel, in addition to reducing the impedance phenomenon, also serves to improve hygiene.
Vaginal sonography is predestined for imaging the following structures and organs:
- Cervix uteri (called cervix for short; cervix): the cervix uteri can be imaged in full length by sonographic examination. Also volume increases, as they occur, for example, in cervical carcinoma can be well represented.
- Corpus uteri (uterine body incl. endometrium/uterine mucosa): In addition to the cervix uteri, the corpus portion of the uterus (size and position determination) can also be imaged with vaginal sonography. Both the cavum uteri (uterine cavity), the endometrium and the myometrium and their possible pathological (pathological) changes can be easily differentiated. Myomas (benign muscular tumors), regardless of whether they are submucosal, intramural, subserosal or pedunculated, can be easily visualized by vaginal sonography.Precise size determination and thus any growth tendency during control examinations are usually possible. Imaging of the endometrium can provide information about cyclic, polyp-like or questionably malignant (malignant) changes. A highly built-up endometrium at menopause (the time of the last spontaneous menstrual period in a woman’s life) or senescence may be indicative of an emerging corpus carcinoma long before bleeding occurs. An echolated area in the cavum uteri is indicative of retained fluid (serometra, haematometra, mucometra). It is also important to check the correct position of intrauterine devices. In postmenopause, endometrial ultrasonography should be performed to clarify postmenopausal bleeding. In this case, the endometrial thickness should not be measurable or < 3 mm (threshold of 3 mm, sensitivity (percentage of diseased patients in whom the disease is detected by the use of the procedure, i.e., a positive finding occurs) of 97%). Otherwise, a histomorphological (fine tissue) clarification is required to exclude benign (benign) endometrial hyperplasia or endometrial carcinoma (uterine cancer).
- Tubal (fallopian): imaging of the tubes (fallopian tubes) is indicated for thickening of the salpinx, which may be due to fluid collections such as a saccosalpinx (sac-shaped deformed fallopian tube (tuba uterina) that is closed at the ampulla end and cystically dilated) or a hematosalpinx (fallopian tube that is filled with blood). Note: The tubes cannot be visualized in normal cases. Due to their irregular course and limited demarcation from the surrounding intestine, they can only be clearly identified in the presence of ascites/abdominal fluid (e.g., shortly after ovulation/ovulation) or in the presence of sactosalpinges. Pathological structures can be reliably detected from a size of > 1 cm.
- Ovary (ovary): vaginal sonography is an important procedure in the diagnosis and treatment of infertility patients and benign (benign) or malignant (malignant) changes in the ovaries. Occasionally, ovarian carcinomas (ovarian cancer) can be detected at a very early stage. This greatly increases the chance of a curative cure. The differentiation of solid and fluid-filled cystic parts is optimally successful with the procedure. In addition to this classification, it is possible to accurately distinguish whether the fluid accumulation is clear or cloudy fluid. The presence of an accumulation of turbid fluid indicates hemorrhage.
- Bladder: vaginal ultrasonography is now firmly established in urogynecology. By positioning the vaginal transducer in the introitus area (introitus sonography), anatomical changes in the urethra, a change in position of the bladder due to a descensus (prolapse) at rest or under stress conditions, the bladder capacity, possibly residual amounts of urine, as well as diverticula, tumors, foreign bodies in the bladder and the bladder wall thickness can be well represented. In incontinence (bladder weakness) and descensus diagnostics, sonography has replaced radiological diagnostics (lateral cystourethro- and the micturition urogram). These examinations can also be performed from the perineum (perineal sonography). However, this requires a different transducer.
To expand the diagnostic spectrum of vaginal sonography serves liquid sonography. This procedure represents a combination of conventional sonography with an additional filling of the cavum uteri using an isotonic saline solution. With the help of the filling, it is now easier to determine whether pathological structures in the cavum leave so-called impressions. An example of a pathological process that could leave an impression is the submucosal myoma. Further notes
- Regarding ovarian cancer screening, the UKCTOCS (UK Collaborative Trial of Ovarian Cancer Screening) trial demonstrated a mortality reduction (reduction in mortality) of 15% with screening with vaginal ultrasonography and CA125 (tumor marker) and 11% with ultrasound screening alone in its analysis. However, both results were not statistically significant.
