Can Ovarian Torsion Be Visualized on CT Abdomen/Pelvis?
Yes, ovarian torsion can be visualized on CT abdomen/pelvis with IV contrast, though ultrasound remains the first-line imaging modality. CT demonstrates 74-95% sensitivity and 80-90% specificity for ovarian torsion and is particularly valuable when ultrasound is inconclusive or when patients present with nonspecific abdominal pain initially attributed to non-gynecologic causes 1.
CT Imaging Findings of Ovarian Torsion
CT demonstrates several characteristic findings that allow diagnosis of ovarian torsion:
- Asymmetrically enlarged ovary with or without an underlying mass is the most consistent finding 1, 2
- Twisted vascular pedicle (swirling pattern) representing the rotated ovarian vessels and supporting ligaments 1, 3
- Abnormal or absent ovarian enhancement indicating compromised blood flow 1, 2
- Deviation of the uterus toward the affected side due to traction from the twisted pedicle 1, 2
- Engorged vessels on the twisted side from venous congestion 1
- Smooth wall thickening of any associated adnexal cystic mass 3
- Fallopian tube thickening and peripheral cystic structures 3, 4
- Free pelvic fluid (ascites) in many cases 3, 4
Clinical Context for CT Use
CT should be used as a second-line imaging modality when ultrasound is equivocal, when there is high suspicion for non-gynecologic emergencies (appendicitis, bowel obstruction), or when rapid diagnosis of a life-threatening condition is required 2. The expanding role of CT in emergency departments means ovarian torsion is increasingly first detected on CT rather than ultrasound 3, 5.
Important Caveat About CT Ordering
- Always order CT of the abdomen AND pelvis together (never pelvis alone) when evaluating generalized abdominal pain, as comprehensive coverage is required 2
- Never use CT when β-hCG is positive due to unnecessary radiation exposure to a potentially viable pregnancy 2
- CT achieves 89% sensitivity for urgent abdominal diagnoses overall, making it valuable when the clinical presentation is nonspecific 2
Critical Diagnostic Principle
A CT scan showing well-visualized, normal-appearing ovaries effectively rules out ovarian torsion, while abnormal pelvic findings or failure to visualize the ovaries in women with pelvic pain necessitates further evaluation 6. In a retrospective review of 167 surgically proven ovarian torsion cases, 100% of available CT reports described an enlarged ovary, ovarian cyst, or adnexal mass of the involved ovary 6.
Algorithmic Approach to Imaging
First-line: Combined transvaginal and transabdominal ultrasound with color and spectral Doppler remains the initial study of choice, documenting ovarian size, masses, peripheral follicle pattern, whirlpool sign, and arterial/venous flow 1, 2
Second-line escalation to CT: Indicated when ultrasound is equivocal, when non-gynecologic emergencies are suspected, or when the clinical presentation initially suggests gastrointestinal pathology 1, 2, 5
Third-line: MRI (80-85% sensitivity) is preferred when ultrasound is nondiagnostic and radiation avoidance is critical, particularly in young patients or when β-hCG status is uncertain 1, 2, 4
Common Pitfall to Avoid
Do not dismiss CT as irrelevant for ovarian torsion diagnosis. While ultrasound is preferred initially, the nonspecific clinical presentation of ovarian torsion frequently mimics appendicitis, diverticulitis, or renal colic, leading many patients to receive CT as their first imaging study 3, 5. Radiologists must be familiar with CT findings to facilitate prompt diagnosis in these clinically unsuspected cases, as early surgery to restore ovarian blood flow prevents permanent irreversible damage 5.