Optimal Imaging for Pelvic Pain

Introduction to Pelvic Pain Imaging

The American College of Radiology recommends a combined transabdominal and transvaginal ultrasound approach for initial assessment of pelvic pain when gynecologic etiology is suspected, as it provides complementary information and is considered the standard of care 1, 2, 3, 4, 5.

Transvaginal ultrasound has a diagnostic accuracy of 79% sensitivity and 76% specificity for ovarian torsion, and 100% sensitivity and 80% specificity for pelvic inflammatory disease with Power Doppler 1, 2, 3, 4, 5.
The overall sensitivity for common pathologies such as ovarian torsion, endometriotic cysts, hemorrhagic cysts, tubo-ovarian abscess, and dermoid cysts is 78.4% 1, 2, 3, 4, 5.

Transabdominal ultrasound provides a larger field of view, allowing for visualization of adnexa positioned high in the pelvis and assessment of free pelvic fluid and pelvic architecture 1, 2, 3, 4, 5, 6, 7.

A transabdominal-only approach is acceptable when transvaginal ultrasound is not feasible, such as in cases of post-treatment vaginal stenosis or fibrosis, juvenile age or sexually naïve patients, patient discomfort or inability to tolerate transvaginal approach, or large fibroids or surgical changes that limit transvaginal visualization 1, 2, 3, 4, 5.

Early detection of ovarian torsion is critical to prevent adnexal necrosis and infertility, and the combined ultrasound approach with Doppler assessment is essential 2, 3, 5.
Abnormal or absent ovarian venous flow has 100% sensitivity and 97% specificity for torsion 2, 3, 5.

The detection rate for moderate-to-severe salpingitis approaches 100% with ultrasound, though mild salpingitis is detected only 25% of the time 1, 3.
Specific findings such as wall thickness >5mm, cogwheel sign, incomplete septa, and cul-de-sac fluid effectively discriminate PID from other pathology 1, 2, 3, 4, 5.

Ordering transvaginal ultrasound alone may miss high-lying adnexal pathology and free fluid critical to diagnosis 1, 2, 3, 4, 5.
Ordering transabdominal ultrasound alone unless transvaginal is contraindicated may sacrifice superior resolution needed to detect subtle ovarian and tubal pathology 6, 7.

If the combined ultrasound examination is nondiagnostic or equivocal, particularly when the differential includes non-gynecologic pathology, proceed to CT abdomen and pelvis with IV contrast 8.
CT demonstrated 89% sensitivity versus 70% for ultrasound in mixed-gender adults with abdominopelvic pain when the differential was broad 8.

The American College of Radiology recommends that the transabdominal component of combined ultrasound provide a wide field of view to visualize high‑lying adnexa, assess free pelvic fluid, and evaluate overall pelvic architecture. 9
The American College of Radiology recommends that the transvaginal component of combined ultrasound deliver superior spatial and contrast resolution for detailed ovarian assessment, with a high‑frequency probe minimizing interference from bowel gas and adipose tissue. 9

The American College of Radiology recommends routine inclusion of color Doppler assessment during combined ultrasound, adding spectral Doppler when indicated, to evaluate vascular flow. 9

The American College of Radiology notes that simple ovarian cysts are readily identified and characterized using the combined transabdominal and transvaginal ultrasound approach. 9
The American College of Radiology suggests that when ultrasound is nondiagnostic, MRI of the pelvis can be employed as a problem‑solving modality, offering approximately 80–85 % sensitivity for ovarian torsion and about 96 % sensitivity for tubo‑ovarian malignancy. 9

The American College of Radiology indicates that CT of the abdomen and pelvis with IV contrast is appropriate when the clinical presentation is nonspecific with a broad differential diagnosis, providing high diagnostic yield. 10
The American College of Radiology indicates that CT should be considered when there is concern for complications such as ovarian torsion with equivocal ultrasound findings. 10