Suspected ovarian (adnexal) torsion
ACR AC Acute Pelvic Pain in the Reproductive Age Group (2023 rev)A time-critical question answered by pelvic ultrasound with Doppler, where the decisive findings are morphological — an enlarged oedematous ovary with peripherally displaced follicles — and normal Doppler flow does NOT exclude the diagnosis.
Sudden severe unilateral pelvic pain, often with nausea and vomiting, frequently with a known ovarian cyst, after ovulation induction, or in pregnancy.
Referenced decision support — confirm against your local protocol.
Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.
- Ultrasound is the only first-line test here and it must not be delayed for anything else. The findings that make the diagnosis are grey-scale: an asymmetrically enlarged, oedematous ovary, follicles displaced to the periphery, a twisted vascular pedicle, and a lead-point cyst. Doppler is supportive — absent flow strongly supports torsion — but the arterial supply is dual and torsion is often intermittent, so preserved flow is common in surgically proven cases.
Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.
How was this decided?
- pathwayany — All patients
Decision support only. Local protocol takes precedence.
Worth asking the referrer (1)
None of these hold the request up. They sharpen the protocol or the plan that follows.
- When did the pain start, and which side?It sets the urgency and tells the sonographer which ovary needs the detailed comparative assessment.
Pathways
Big forks are separate pathways; the first whose conditions match is the one used.
All patients
Matches your inputsDefault| Role | Study & protocol | Why this answers the question |
|---|---|---|
| First line | Ultrasound pelvis (transabdominal ± transvaginal) Pelvic ultrasound — transabdominal and transvaginal usually appropriate | Ultrasound is the only first-line test here and it must not be delayed for anything else. The findings that make the diagnosis are grey-scale: an asymmetrically enlarged, oedematous ovary, follicles displaced to the periphery, a twisted vascular pedicle, and a lead-point cyst. Doppler is supportive — absent flow strongly supports torsion — but the arterial supply is dual and torsion is often intermittent, so preserved flow is common in surgically proven cases. |
| Problem solving | MRI Pelvis (Gynaecological) MRI Pelvis — general gynaecological | Occasionally useful in the stable patient whose ultrasound is indeterminate and whose surgery is not imminent — it shows ovarian stromal oedema, haemorrhage and the twisted pedicle well. It is a problem-solving study for an uncertain diagnosis, never a step to be completed before a patient with convincing torsion goes to theatre. |
- In a girl or a woman who has never been sexually active, the examination is transabdominal with a full bladder. That is a technique decision for the scanning list, not a reason to change or refuse the study.
Pitfalls
- The central one: reporting "normal arterial and venous flow, torsion excluded". Preserved Doppler flow is well described in surgically confirmed torsion, and the published series show it delaying management.
- Scanning only the painful side. The diagnosis is comparative — ovarian volume asymmetry is one of the strongest signs.
- Sending the patient for CT first because the presentation looked like appendicitis. If the ovary is the question, ultrasound is the answer.
- Treating an ultrasound reported as normal as the end of the pathway when the history is convincing; intermittent torsion detorts between the pain and the scan.
- Booking the study routinely because the request did not use the word "urgent".
- Excluding torsion in a girl or a young woman because there is no ovarian mass. A substantial minority of paediatric and adolescent torsions occur in a morphologically normal ovary with no lead point at all, and the only sign is the asymmetrically enlarged oedematous ovary — which is why both ovaries are measured and compared even when neither contains a cyst.
Priors — what to pull first
- A previously documented cyst gives the lead point and a baseline ovarian size, which makes today’s asymmetry interpretable.
- Previous torsion or oophorectomy on the other side changes both the pre-test probability and the surgical stakes.
What makes a good request
- Ovarian salvage depends on detorsion happening early, so the scan should be treated as an emergency examination and not booked into the next available routine slot.
- Torsion is a clinical diagnosis that imaging supports. A convincing history with an equivocal scan is a reason to talk to the gynaecologist, not to reassure.
Scoring this once it is done
The classification and risk tools this question ends in.
How these studies are acquired
Contrast, phases and timing for every study on the pathways above.
Confirm locally
- Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
- Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.
References
- ACR Appropriateness Criteria — Acute Pelvic Pain in the Reproductive Age Group: 2023 Update · ACR Appropriateness Criteria
- Diagnosis of ovarian torsion: is it time to forget about Doppler? (J Obstet Gynaecol Can 2018) · Primary literature
- Usefulness of Doppler sonography in the diagnosis of ovarian torsion (Fertil Steril) · Primary literature
- Diagnosis of ovarian torsion: is it time to forget about Doppler? J Obstet Gynaecol Can 2018 · Primary literature
Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.