Ovarian Torsion Diagnosis

Introduction to Diagnostic Approaches

The American College of Radiology recommends performing both transvaginal and transabdominal ultrasound together as the initial imaging approach for suspected ovarian torsion, providing complementary diagnostic information 1, 2, 3.

Transvaginal ultrasound has superior resolution for detecting subtle ovarian and tubal pathology, with a sensitivity of 83.3% specifically for ovarian torsion 1, 3, 4.
Transvaginal ultrasound provides better visualization of ovarian architecture, peripheral follicles, and the whirlpool sign 1, 5.
Transabdominal ultrasound offers a larger field of view to assess adnexa positioned high in the pelvis and better evaluation of free pelvic fluid and overall pelvic architecture 1, 2, 4.

A unilaterally enlarged ovary (>4 cm or volume >20 cm³) is found in up to 74% of ovarian torsion cases 1, 3, 5.
Peripheral follicles in a "string of pearls" pattern are a key ultrasound feature of ovarian torsion 1, 5.
The whirlpool sign (twisted vascular pedicle) is present in 90% of patients with confirmed torsion at laparoscopy 3, 6, 5, 4.
Abnormal or absent ovarian venous flow on Doppler has 100% sensitivity and 97% specificity for ovarian torsion 3, 6, 5, 4.

The combined ultrasound approach with Doppler has an overall accuracy of 96% for adnexal torsion 1, 3.
If the combined ultrasound examination is nondiagnostic or equivocal, proceed to MRI (80-85% sensitivity, no radiation) as the preferred second-line modality 6, 5.
Consider CT abdomen/pelvis with IV contrast (74-95% sensitivity) if MRI is unavailable or when non-gynecologic pathology is in the differential 7, 4.