Transabdominal ultrasound

Role of the Method in Diagnostic Imaging

Ultrasound scanning through the anterior abdominal wall is one of the primary imaging modalities in gynecology. The study has distinct advantages over other imaging techniques: it is accessible, relatively inexpensive, and allows for multiplanar evaluation of anatomical structures.

Transabdominal scanning is rarely used in isolation; rather, it is part of a comprehensive ultrasound examination, complementing the transvaginal approach (TVUS). If ultrasound findings are equivocal (e.g., in acute pelvic pain), computed tomography (CT) may be ordered, although magnetic resonance imaging (MRI) is currently preferred for benign pathologies.

Main indications for the procedure

The range of clinical scenarios requiring transabdominal ultrasound is quite broad. Primarily, the method is used for:

• characterizing pelvic mass lesions and ovarian tumors;
• identifying the causes of acute pelvic pain;
• diagnosing uterine enlargement;
• identifying the causes of postmenopausal bleeding.

Additionally, ultrasound provides reliable navigation during tissue drainage or biopsy. Special attention is paid to obstetric and gynecological complications. For instance, when ectopic pregnancy is suspected or in cases presenting with clinical features of incomplete abortion, comprehensive ultrasound is strictly indicated. Its main goal is to confirm complete pregnancy termination. In such situations, the use of two approaches is mandatory; if vaginal scanning is not feasible, the abdominal method is combined with the transrectal approach.

Imaging of Endometrial Pathologies

Although the transvaginal probe is superior to the abdominal probe for detailed evaluation of the uterine lining, initial changes are often detected during transabdominal screening. The most frequent, yet non-specific, ultrasound sign is endometrial thickening, which cannot be visually distinguished from a benign polyp or hyperplasia. In postmenopausal women, the normal mucosal thickness should be strictly less than 4 mm. If this threshold is exceeded, the patient is referred for hysteroscopy.

Suspicion of malignancy arises when the endometrial surface is irregular or the border between the mucosa and the muscular layer (endometrial/myometrial junction) is disrupted. To improve diagnostic accuracy, 3D ultrasound and colour Doppler imaging are recommended. On Doppler ultrasound, a malignant process may appear as a heterogeneous polypoid mass with internal vascularity distending the uterine cavity.

Invasion Assessment and Alternative Methods

Evaluation of myometrial invasion depth is based on visualizing the hypoechoic halo. This halo surrounds the outer layer of the endometrium, and its continuity is used to determine the degree of invasion. However, ultrasound capabilities are limited here: the method can reliably assess disease only in stage I. MRI is used for more advanced staging of endometrial cancer (according to the FIGO system).

When standard ultrasound reveals suspicious lesions, diagnostics are supplemented with sonohysterography. The procedure involves inserting a 5F balloon catheter through the cervix followed by the instillation of sterile saline under direct ultrasound guidance. This helps to closely examine intracavitary polyps and asymmetric mucosal thickening without using ionizing radiation.

Class and exam questions

What else to study on this topic

• Transvaginal Ultrasound (TVUS): Technique and Advantages
• Sonohysterography: Indications, Instillation Technique, and Differences from HSG
• Ultrasound Signs and Color Doppler Imaging in Endometrial Cancer
• MRI in FIGO Staging of Endometrial Cancer
• The Role of Diagnostic Imaging in Congenital Mullerian Duct Anomalies

Other topics in the section "Diagnostic Radiology of the Abdominal Organs"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.