Can ovarian torsion be detected on contrast‑enhanced CT of the abdomen and pelvis in an adult female with acute lower abdominal pain?

Can Ovarian Torsion Be Detected on CT Abdomen?

Yes, CT abdomen and pelvis with IV contrast can detect ovarian torsion and should be used as a second-line imaging modality when ultrasound is inconclusive, with a negative contrast-enhanced CT having 100% negative predictive value for ruling out ovarian torsion. 1, 2

Primary Imaging Approach

• Ultrasound remains the first-line imaging modality for suspected ovarian torsion, with transvaginal combined with transabdominal views providing the most comprehensive assessment 1
• Doppler ultrasound demonstrates 80% sensitivity and 88% specificity for diagnosing ovarian torsion 1
• The whirlpool sign on ultrasound is highly specific, with 90% of patients having confirmed adnexal torsion on laparoscopy 1

When CT Should Be Used

CT abdomen/pelvis with IV contrast serves as the appropriate second-line imaging modality in the following scenarios: 1

• When ultrasound findings are inconclusive or equivocal 1
• When clinical presentation is nonspecific with poorly localized pain 3
• When there is concern for non-gynecologic pathology 3
• CT demonstrates 89% sensitivity for urgent diagnoses compared to 70% for ultrasound in nonspecific presentations 3

Specific CT Findings of Ovarian Torsion

CT with IV contrast demonstrates the following findings with 74-95% sensitivity and 80-90% specificity: 1

• Asymmetrically enlarged ovary (>5 cm) with or without an underlying mass 1, 4
• Twisted pedicle (swirling of vascular pedicle) 1, 5
• Abnormal or absent ovarian enhancement (hypoenhancing, featureless ovary) 1, 5
• Deviation of the uterus to the side of the twist 1, 5
• Engorged vessels on the twisted side 1
• Smooth wall thickening of adnexal cystic mass 5
• Fallopian tube thickening 5
• Peripheral cystic structures 5
• Free pelvic fluid/ascites 5

Critical Diagnostic Performance

A negative contrast-enhanced CT examination has 100% negative predictive value for ovarian torsion - meaning if the CT shows well-visualized normal-appearing ovaries, ovarian torsion is effectively ruled out 2, 4

• In a retrospective study of 283 cases, no negative CT examinations were associated with positive ultrasound findings for ovarian torsion 2
• All surgically proven cases of ovarian torsion over 20 years showed abnormalities on CT (enlarged ovary, ovarian cyst, or adnexal mass) 4

Important Caveats and Pitfalls

Intravenous contrast is essential - the diagnostic performance data specifically refers to contrast-enhanced CT, not non-contrast studies 1, 3

CT is not the preferred initial test despite its diagnostic capability, because: 1

• Ultrasound provides superior initial evaluation without radiation exposure
• CT is typically reserved for when ultrasound is nondiagnostic or unavailable

Emergency physicians and radiologists must actively look for ovarian torsion findings on CT performed for nonspecific abdominal pain, as this diagnosis can be missed if not specifically considered 6

Clinical Algorithm

1. Order pelvic ultrasound with Doppler as first-line imaging for suspected ovarian torsion 1
2. If ultrasound is inconclusive or nondiagnostic, proceed to contrast-enhanced CT abdomen/pelvis 1
3. If CT shows any abnormality of the ovaries (enlarged ovary, cyst, mass, or failure to visualize ovaries), obtain urgent gynecology consultation 4
4. If CT shows well-visualized normal ovaries, ovarian torsion is ruled out 2, 4
5. Do not order additional ultrasound after a negative contrast-enhanced CT specifically to evaluate for torsion, as this adds no diagnostic value 2