Diagnostic Ultrasound - Abdomen and Pelvis

Adnexal/Ovarian Torsion
Diagnoses: Female Pelvis
Pelvic Inflammatory Disease
• Uniformly thickened and dilated fallopian tubes
• Pyosalpinx
○ Contains low-level echoes or fluid-fluid level
• ± enlarged ovaries secondary to oophoritis
○ Normal or increased flow pattern on color Doppler
• ± tubo-ovarian abscess
○ Complex cystic/solid masses
• "Indefinite uterus" sign
○ Obscuration of posterior margin of myometrium by
inflammation
Ectopic Pregnancy
• Positive β-hCG
• No evidence of intrauterine pregnancy on endovaginal
sonography
• Adnexal mass separate from ovary
○ Tubal ring with increased flow ("ring of fire")
• Visualization of embryo or yolk sac within tubal gestational
sac
• Free fluid in pelvis and Morison pouch from
hemoperitoneum
PATHOLOGY
General Features
• Etiology
○ In adults, 50-90% have associated ovarian mass, usually
benign
– Large physiologic follicular cyst or corpus luteum cyst
is most common
– Dermoid, paraovarian cyst, and epithelial and stromal
tumors can also serve as lead points for torsion
○ Infants and children rarely have associated mass
– Hypermobility due to long mesosalpinx
○ Isolated tubal torsion may occur due to hydrosalpinx,
hematosalpinx, tubal neoplasms, tubal ligation, tubal
hypermotility, and hydatid of Morgagni
Gross Pathologic & Surgical Features
• Torsion of both ovary and fallopian tube most commonly
found at surgery
○ Isolated torsed fallopian tube possible
• Ovarian torsion occurs around suspensory ligament of
ovary
○ Posterior fold of broad ligament that contains ovarian
vessels
• Twist ranges 180-720°
• Sequential venous, lymphatic, and arterial obstruction
• Earliest pathologic changes include edema and microscopic
hemorrhage within ovary
○ Begins centrally
• Prominent fluid-filled follicles displaced peripherally by
central edema
• Late findings include hemorrhagic infarction
○ Cystic spaces filled with blood and associated
hemoperitoneum
• Calcified mass in chronic cases
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Severe unremitting acute pelvic pain is most common
symptom
– Pain may be intermittent torsion/detorsion
○ Adnexal mass may or may not be palpable
○ Vomiting is common
○ Fever if ovary is infarcted
Demographics
• Epidemiology
○ 2-3% of all gynecologic emergencies
○ Most common in first 3 decades
○ More common during pregnancy
– Usually before 20 weeks
– As uterus enlarges, ovaries are pushed out of pelvis
increasing risk of torsion
○ Increased risk in women undergoing ovarian stimulation
○ Increased risk in women with prior pelvic or abdominal
surgery
Natural History & Prognosis
• Spontaneous detorsion can recur
○ Massive ovarian edema felt to result from episodes of
intermittent torsion with detorsion
– Usually long history of intermittent pain
• Presence of venous flow indicates viable ovary
• If no flow seen, ovary is infarcted
Treatment
• Surgical untwisting in noninfarcted adnexa either with
laparoscopy or open surgery
○ Preservation of ovary is possible if normal blood flow is
restored after detorsing ovary
• Careful examination and removal of any mass serving as
lead point
• Salpingo-oophorectomy in infarcted ovary
DIAGNOSTIC CHECKLIST
Consider
• Ectopic pregnancy in pregnant patient
Image Interpretation Pearls
• Absent venous flow in enlarged echogenic ovary with
prominent peripheral follicles is earliest reliable sign
• Presence of normal blood flow does not exclude torsion
• Always look for underlying mass
SELECTED REFERENCES
1. Lourenco AP et al: Ovarian and tubal torsion: imaging findings on US, CT, and
MRI. Emerg Radiol. 21(2):179-87, 2014
2. Narayanan S et al: Fallopian tube torsion in the pediatric age group:
radiologic evaluation. J Ultrasound Med. 33(9):1697-704, 2014
3. Sasaki KJ et al: Adnexal torsion: review of the literature. J Minim Invasive
Gynecol. 21(2):196-202, 2014
4. Duigenan S et al: Ovarian torsion: diagnostic features on CT and MRI with
pathologic correlation. AJR Am J Roentgenol. 198(2):W122-31, 2012
5. Sibal M: Follicular ring sign: a simple sonographic sign for early diagnosis of
ovarian torsion. J Ultrasound Med. 31(11):1803-9, 2012
6. Wilkinson C et al: Adnexal torsion -- a multimodality imaging review. Clin
Radiol. 67(5):476-83, 2012
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