Table 1 US, CT and MRI indications and findings
From: Radiological appearances of gynaecological emergencies
US | CT | MRI | |
|---|---|---|---|
Simple ovarian cysts | Indicated | Not indicated | Not indicated |
Anechoic 3-6 cm cyst, with thin wall <3 mm and minimal thin septations | Well-defined cystic adnexal mass of low attenuation and smooth well-defined wall | Well-defined cystic adnexal mass of low T1 and high T2 signal intensity and smoothly enhancing wall | |
Haemorrhagic ovarian cyst | Indicated | Not indicated unless suspected cyst rupture with severe pain | Not indicated unless a cyst is considered indeterminate on US |
Isoechoic to ovarian stoma when acute. Develops fine, reticular “spider-web” or lace-like pattern. Vascular wall with avascular internal clot material. If ruptured, then free pelvic fluid with low-level echos is seen | Hyperdense mass within the adnexa. Smooth enhancing cyst wall. If ruptured, then high-density free fluid is seen in pelvis and there may be contrast pooling in the pelvis on delayed images in cases of rupture | Appearance depends on age of blood. Typically, high T1 material is seen within the cyst. Cyst rupture may demonstrate a combination of low and high T1 and T2 free fluid in pelvis | |
Endometriotic cysts | Indicated | Not indicated unless suspected acute rupture | Not indicated unless a cyst is considered indeterminate on US |
Ovarian cyst containing ground–glass appearance, with homogenous internal echogenicity. May be multiple | Ruptured endometriotic cyst may be associated with loculated dense ascites often confined to the pelvic cavity due to adhesions | Typically T1 hyperintense cysts with T2 shading; frequently bilateral. Chronic fibrotic changes in pouch of Douglas may be seen | |
Adnexal torsion | Indicated although of low sensitivity | May be undertaken due to acute pain with unclear diagnosis | Not indicated unless the adnexal mass is considered indeterminate |
Doppler whirlpool sign with corkscrew appearance of twisted vascular pedicle and an enlarged ovary with peripherally located follicles | Twisted vascular pedicle | Oedema of ovarian stroma. There may be absence of vascular supply and low level enhancement in the solid component of the ovarian mass | |
Wall thickening of torted adnexal mass. Poor contrast enhancement of internal solid components | |||
Fibroid (complications) | Indicated | May be undertaken if patient has acute pain | Not usually indicated. May be used to differentiate a degenerating fibroid from a complex adnexal mass |
Degeneration gives a complex US appearance with areas of cystic change | Degeneration gives cystic hypodense appearance of fibroid mass | Cystic degeneration is seen as complex high T2 signal intensity within a fibroid | |
Doppler shows circumferential vascularity | Can be difficult to distinguish from a complex ovarian cyst when large | Red degeneration within a fibroid is seen as | |
Absence of flow if torted | high T1 signal centrally due to blood with low T2 signal at periphery due to haemosiderin deposition | ||
Submucosal pedunculated fibroid may extend into endocervix or vagina from a stalk and may tort | |||
Pelvic inflammatory disease | Indicated | Not usually indicated but may be done if diagnosis is uncertain | Not indicated unless the diagnosis is uncertain and US is indeterminate |
Clinical signs are key to diagnosis. US may be normal. Thickened endometrium or pyosalpinx may be seen | Tubo-ovarian abscesses appear as bilateral thick-walled complex enhancing masses with tubal configuration and surrounding inflammation | Tubo-ovarian abcesses appear as complex thick-walled enhancing adnexal masses with surrounding inflammation |