Brief description of imaging findings in adnexal torsion. Source: Diagnostic Imaging - Gynecology, 1st edition, 2007; Radiopaedia.

1. Adnexal torsion – imaging findings

2. Ultrasound findings
The most important diagnostic signs
Enlarged ovary > 4-5 cm
Enlarged echogenic stroma due to venous obstruction
Peripherally displaced follicles
Ovary sensitive to transducer pressure
! Always look for a large ovarian cyst / mass

3. Ultrasound findings
Do NOT eliminate the diagnosis if
no whirlpool sign – twisted vascular pedicle
normal blood flow – because of the dual blood
supply of the ovary (uterine and ovarian artery);
intermittent torsion

4. Other findings
Hemorrhagic follicles
Thickened fallopian tube / hematosalpinx
Absent venous +/- arterial flow
Midline ascended ovary, tractioned uterus
Echogenic pelvic fat
Free fluid

5. Adnexal torsion – CT findings
Hemorrhagic adnexa – infarction
 look at non-contrast images
Hematosalpinx
Beak sign due to twisted fallopian tube
Twisted vascular pedicle
Ovarian mass
Fat stranding
Free fluid

6. Adnexal torsion – MRI findings
T1 hyper – hematosalpinx, hemorrhagic cyst
T2 hyper – enlarged edematous ovarian stroma