From the Guidelines
Transvaginal ultrasound, combined with transabdominal ultrasound of the pelvis with Doppler, is the most appropriate initial imaging study for patients with abnormal uterine bleeding. This approach is supported by the American College of Radiology Appropriateness Criteria, which are evidence-based guidelines that are reviewed annually by a multidisciplinary expert panel 1. The use of transvaginal ultrasound provides superior visualization of the endometrium, myometrium, and other pelvic structures due to the closer proximity of the ultrasound probe to these organs.
When evaluating abnormal uterine bleeding, transvaginal ultrasound can accurately measure endometrial thickness, detect endometrial polyps, fibroids, adenomyosis, and identify structural causes of bleeding. The procedure involves inserting a probe into the vagina while the patient has an empty bladder, which is more comfortable than the full bladder required for transabdominal ultrasound. Key benefits of this approach include:
- Improved resolution for better characterization of endometrial abnormalities
- More accurate measurements, which are crucial for determining appropriate management of abnormal uterine bleeding
- The ability to detect a range of conditions that may be causing the abnormal bleeding, allowing for targeted treatment plans
According to the guidelines, if the uterus is incompletely visualized with the initial ultrasound, MRI of the pelvis without and with contrast is the next appropriate imaging study, unless a polyp is suspected on the original ultrasound, then sonohysterography can be performed 1. This stepped approach ensures that patients receive the most appropriate imaging for their specific condition, minimizing unnecessary tests and procedures.
From the Research
Assessment of Abnormal Uterine Bleeding
- Transvaginal ultrasound is considered the first-line imaging test for evaluating abnormal uterine bleeding in both premenopausal and postmenopausal women 2.
- It can diagnose structural causes of abnormal bleeding, such as polyps, adenomyosis, leiomyomas, hyperplasia, and malignancy, and can also be beneficial in making the diagnosis of ovulatory dysfunction 2.
Comparison with Other Imaging Techniques
- Transvaginal ultrasound plays a pivotal role in the management of non-pregnant women with abnormal vaginal bleeding, with no other imaging technique having a role in the triage of these women 3.
- While transvaginal ultrasound may not be able to diagnose all causes of abnormal vaginal bleeding before menopause, such as infection or problems with intrauterine contraceptive devices, it can still be helpful in some cases 3.
Diagnostic Accuracy
- The diagnostic accuracy of transvaginal ultrasound in detecting endometrial polyps can be improved with the addition of saline infusion sonohysterography (SIS) 4.
- Even when diagnostic confidence for the presence of polyps is high, SIS has a higher positive predictive value than transvaginal ultrasound alone 4.
Clinical Application
- Transvaginal ultrasound can be used to plan surgical procedures, such as hysteroscopy or laparotomy, and can help determine when no further surgical evaluation is necessary 5.
- A structured transvaginal ultrasound approach can be implemented in clinical practice to simplify the diagnosis of abnormal uterine bleeding and determine when additional invasive investigations are required 6.