From the Guidelines
CT evaluation has a sensitivity of 74% to 95% for the diagnosis of adnexal torsion, including ovarian torsion. When evaluating CT sensitivity for ovarian torsion, it is essential to consider the range of sensitivity reported in the literature, which is based on 2 case-control studies and 1 cohort study (n = 3,232) 1. The CT findings that suggest adnexal torsion include an asymmetrically enlarged ovary with or without an underlying mass and a twisted pedicle, which can be better detected with multiplanar CT reformations 1.
Other relevant CT findings for ovarian torsion may include subacute ovarian hematoma, abnormal or absent ovarian enhancement, ascites, deviation of the uterus to the side of the twist, engorged vessels on the twisted side, and fallopian tube thickening 1. While CT can be useful in diagnosing ovarian torsion, it is crucial to consider the clinical presentation and other imaging modalities, such as ultrasound and MRI, which may offer higher sensitivity and specificity for certain diagnoses.
In the context of acute pelvic pain with suspected gynecological etiology and negative b-hCG, the initial imaging modality of choice may not be CT abdomen and pelvis with IV contrast, unless a life-threatening diagnosis is considered or other imaging modalities are inconclusive 1. Ultimately, the diagnosis of ovarian torsion remains clinical, and imaging should not delay surgical intervention when clinical suspicion is high, as timely treatment is crucial for ovarian preservation.
From the Research
CT Sensitivity for Ovarian Torsion
- The sensitivity of CT for ovarian torsion was found to be 100.0% in one study 2, while another study reported a sensitivity of 90.0% for reader 2 2.
- A study comparing the sensitivity and specificity of ultrasonography and computed tomography for diagnosis in the emergency department found that CT was 100.0% sensitive (95% CI, 83.9-100.0%) and 85.0% specific (95% CI, 64.0-94.5%) for reader 1, while 90.0% sensitive (95% CI, 69.9-97.2%) and 90.0% specific (95% CI, 69.9-97.2%) for reader 2 2.
- Interobserver agreement for CT was excellent (Kappa=0.85) in one study 2.
Comparison with Other Imaging Modalities
- Ultrasound is the first-line imaging modality of choice for evaluation of ovarian torsion, but CT may be used in emergency settings due to its increasing usage 3, 4, 5.
- MRI is useful as a problem-solving tool in patients with equivocal or non-diagnostic ultrasonography studies 3, 4, 5.
- The diagnostic performance of CT is not shown to be significantly different from that of US in identifying ovarian torsion in one study 2.
Clinical Implications
- Early diagnosis of ovarian torsion is crucial to prevent permanent irreversible damage, and CT can play a role in facilitating prompt surgery 3, 4, 5.
- Familiarity with the CT features of ovarian torsion is essential for radiologists to improve the likelihood of timely diagnosis and therefore improved clinical outcomes 3, 4, 5.