Diagnostic Ultrasound - Abdomen and Pelvis

Adnexal/Ovarian Torsion
Diagnoses: Female Pelvis
TERMINOLOGY
• Adnexal torsion is more accurate term than ovarian torsion,
as torsion usually also includes fallopian tube
IMAGING
• Ovary > 4 cm long or > 20 cm³ in volume
• Ultrasound
○ Enlarged, heterogeneously echogenic ovarian stroma
○ Multiple small, peripheral, fluid-filled follicles displaced
due to edematous stroma &/or mass
○ Whirlpool sign: Coiled, twisted pedicle
○ Flow pattern depends on degree of vascular obstruction
and chronicity of torsion
○ Venous flow affected 1st
○ Due to dual arterial blood supply to ovary, arterial flow
may be preserved
• CT
○ Twisted pedicle most specific sign but seen in < 1/3 of
cases (use multiplanar reformations)
KEY FACTS
○ Heterogeneous, minimal, or absent enhancement
indicates evolution from ischemia to infarction
TOP DIFFERENTIAL DIAGNOSES
• Hemorrhagic corpus luteum
• Pelvic inflammatory disease
• Ectopic pregnancy
PATHOLOGY
• In adults, 50-90% have associated ovarian mass that serves
as lead point
○ Large physiologic follicular cyst or corpus luteum cyst
most common, followed by dermoid
• Presence of venous flow indicates viable ovary
DIAGNOSTIC CHECKLIST
• Presence of normal blood flow does not exclude torsion
• Always look for underlying mass
(Left) Longitudinal
endovaginal ultrasound with
adnexal torsion shows an
enlarged, 6 cm ovary ſt
containing a hemorrhagic cyst
with multiple peripheral
follicles st. (Right)
Endovaginal pulse wave
Doppler ultrasound in the
same patient with adnexal
torsion shows low-resistance
arterial flow in the ovary. It is
important to remember that
the presence of blood flow
does not exclude ovarian
torsion.
(Left) Endovaginal ultrasound
in a woman with acute pelvic
pain shows a large cyst in the
ovary with adjacent
edematous parenchyma ſt
with no color Doppler signal.
Alternating red and blue color
signal represents a twisted
vascular pedicle, which is best
seen during real time. (Right)
Intraoperative photo in the
same patient looking caudally
confirms torsion and shows
dusky infarcted right ovary
(grasped) and twisted vascular
pedicle ſt.
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