What is the best initial diagnostic tool to evaluate blood flow to the ovaries in a female patient of reproductive age presenting with symptoms of compromised ovarian blood flow, such as pelvic pain or suspected ovarian torsion?

Ultrasound Evaluation of Ovarian Blood Flow

Transvaginal ultrasound with color and spectral Doppler is the first-line imaging modality to evaluate blood flow to the ovaries, particularly when ovarian torsion is suspected. 1, 2

Recommended Ultrasound Approach

A combined transabdominal and transvaginal ultrasound with Doppler should be performed together as complementary studies to provide the most comprehensive assessment of ovarian blood flow. 1, 2

Key Technical Components

• Color Doppler is a standard component of pelvic ultrasound examination and should be performed simultaneously with grayscale imaging. 1

• Spectral Doppler should be added when there is concern for compromised blood flow, particularly in suspected torsion cases. 1

• The transvaginal approach provides superior visualization due to high-frequency probe proximity to the ovaries with less interference from bowel gas and adipose tissue. 1

• The transabdominal component offers a larger field of view to assess the entire pelvis, including free fluid and the relationship of structures. 1

Critical Doppler Findings for Blood Flow Assessment

High-Sensitivity Findings

• Abnormal or absent venous flow has 100% sensitivity and 97% specificity for ovarian torsion, making it the most reliable Doppler finding. 2

• The whirlpool sign (twisted vascular pedicle) has 90% sensitivity in patients with surgically confirmed torsion. 2

• Overall Doppler ultrasound demonstrates 80% sensitivity and 88% specificity for diagnosing ovarian torsion. 2

Important Pitfall to Avoid

Normal arterial blood flow does NOT rule out ovarian torsion, as torsion can be intermittent or partial, and venous obstruction typically occurs before arterial compromise. 2, 3, 4 This is a critical concept—the presence of arterial flow may actually suggest the ovary is still viable, especially if flow is present centrally. 4, 5

Additional Ultrasound Findings Suggesting Compromised Flow

• Unilaterally enlarged ovary (>4 cm or volume >20 cm³). 2, 3

• Peripheral follicles (present in up to 74% of torsion cases). 2

• Free pelvic fluid. 4

• Coexistent mass within the affected ovary. 4

When Ultrasound is Inconclusive

If ultrasound findings are equivocal but clinical suspicion for compromised ovarian blood flow remains high:

• MRI provides 80-85% sensitivity for torsion with findings of enlarged ovary, stromal edema, and absent/diminished enhancement. 2, 3

• CT may demonstrate an enlarged, featureless, hypoenhancing ovary with swirling of the vascular pedicle. 2, 3

Clinical Context

Ultrasound is particularly critical because early detection of compromised ovarian blood flow is essential to prevent adnexal necrosis and preserve fertility. 2 The combined grayscale and Doppler approach has proven superior to grayscale alone (which has only 79% sensitivity and 76% specificity). 2