CT Scan with Contrast for Ovarian Torsion Diagnosis
CT scan with contrast is a second-line imaging modality for ovarian torsion that should be used when ultrasound is inconclusive or unavailable, but it can reliably diagnose torsion when specific CT findings are carefully evaluated. 1
Primary Role and Clinical Context
- Ultrasound remains the first-line imaging modality for suspected ovarian torsion, not CT scan 1
- CT has an expanding role because it is increasingly used in emergency departments for acute abdominal pain evaluation, and ovarian torsion frequently mimics non-gynecological conditions like appendicitis, renal colic, or diverticulitis 1, 2, 3
- When patients present with non-specific abdominal pain, CT may be the initial imaging obtained before ovarian torsion is clinically suspected 2, 3
Diagnostic Performance of CT with Contrast
- At least one positive CT finding is present in 100% of surgically proven ovarian torsion cases, making a normal-appearing ovary on CT highly reliable for ruling out torsion 3, 4
- All CT scans in patients with proven ovarian torsion show abnormalities of the involved ovary (enlarged ovary, ovarian cyst, or adnexal mass) 4
- A CT scan showing well-visualized, normal-appearing ovaries effectively rules out ovarian torsion, while abnormal pelvic findings or failure to visualize the ovaries necessitates further evaluation 4
Specific CT Findings to Look For
The American College of Radiology identifies these key CT findings with contrast 1:
- Twisted pedicle (swirling of vascular pedicle) - present in 100% of cases 3
- Asymmetrically enlarged ovary with or without an underlying mass - present in 93.3% of cases 1, 3
- Abnormal or absent ovarian enhancement (hypoenhancing, featureless ovary) - present in 46.4% of cases 1, 3
- Deviation of the uterus to the side of the twist - present in 43.4% of cases 1, 3
- Peripheral follicles (peripherally displaced follicles) - present in 57.1% of cases 3
- Fallopian tube thickening or hydrosalpinx - present in 46.7% of cases 5, 3
- Ascites or free pelvic fluid - present in 73.3% of cases 5, 3
- Engorged vessels on the twisted side 1
- Smooth wall thickening of twisted adnexal cystic mass 5
- Subacute ovarian hematoma 1
Clinical Algorithm for CT Use
When to use CT with contrast:
- Ultrasound is inconclusive but clinical suspicion remains high 1
- Patient presents with acute abdominal pain attributed to non-gynecological causes (appendicitis, renal colic, bowel pathology) 2, 3
- CT is the only immediately available imaging modality in the emergency setting 3
When CT findings are positive:
- Immediate gynecologic consultation for urgent surgical management is required 1
- Do not delay surgery to obtain confirmatory ultrasound if CT findings are diagnostic 3
When CT shows normal ovaries:
- Ovarian torsion is effectively ruled out 4
- Consider alternative diagnoses for the patient's symptoms 4
Critical Pitfalls to Avoid
- Do not assume CT is inadequate for diagnosing ovarian torsion - when CT signs are carefully evaluated, it can make the diagnosis and prompt immediate surgical referral, reducing delays from obtaining additional imaging 3
- Intravenous contrast is essential for optimal detection and characterization of ovarian enhancement abnormalities and vascular pedicle twisting 1
- Be aware that ovarian torsion can mimic urinary tract infection symptoms (dysuria, urgency) due to anatomical proximity and inflammation affecting nearby structures 1
- Remember that the presence of an underlying ovarian mass (most commonly mature cystic teratoma) is typical in ovarian torsion cases 5
Advantages of CT in Emergency Settings
- CT can diagnose ovarian torsion in clinically unsuspected cases where non-gynecological pathology was initially considered 2
- Early correct diagnosis by radiologists facilitates prompt surgery to restore ovarian blood flow and prevent permanent irreversible damage 2
- CT provides comprehensive abdominal and pelvic evaluation when the differential diagnosis is broad 2