Pearls and Pitfalls inDiagnosis of OvarianTorsion

Dr. Omneya Nagy Elmakhzangy Special Fetal Care Unit Ain Shams University

•Ovarian torsion is partial or complete rotation of the ovarian vascular pedicle causing obstruction to venous outflow and arterial inflow.

•It accounts for 2.7-3 % of all gynecologic emergencies , ranking fifth .

•Clinical presentation of ovarian torsion is variable, and physical examination is often inconclusive.

•Early Diagnosis increases the chances of saving the ovary and adnexa, in addition to preventing life threatening complications as thrombophlebitis and peritonitis .

•The Key in both clinical and ultrasound diagnosis is maintaining a high index of suspision .

So Can Ultrasound be helpful ?

•Imaging pearls : Comparison with the asymptomatic contralateral side is typically very helpful.

•Torsion is more common in the right ovary possibly due to supportive effect provided by sigmoid colon to the left one.

Scanning Modalities

2D Gray Scale Ultrasound

•The most constant finding in ovarian torsion is a large ovary (> 4 cm) with the ovarian volume enlarging up to 28 folds.

Torsion in a normal sized ovary?•Commonly occurs in young children with

developmental abnormalities, such as excessively long Fallopian tubes or an absent mesosalpinx.

Ultrasound with detectable cause of Ovarian Enlargement

•1-Large, heavy cysts and cystic neoplasms, such as benign mature cystic teratomas (The most common tumor predisposed for ovarian torsion)

•2- Hemorrhagic cysts, and cystadenomas (>5 cm)

•3- Ovarian Hyperstimulation Syndrome.

Ultrasound Signs Suggestive of torsion

•Peripheral cysts (the string of pearls sign) can be seen in polycystic ovary disease, but the morphology of the ovary is usually normal; conversely, the cysts are unilateral in ovarian torsion with accompanying abnormal morphology of the ovary (congested ovarian stroma).

•The “whirlpool” sign is visible as a clockwise or counterclockwise wrapping of the hypoechoic vessels around the central axis giving the characteristic “Target” appearance of the twisted vascular pedicle.

Gray Scale and Color Doppler Whirlpool sign

•Presence of anechoic pelvic free fluid

•Gray-Scale US Features of Ovarian Torsion

•Unilateral enlarged ovary (>4 cm)•String of pearls sign•Coexistent mass within the twisted ovary•Free pelvic fluid•Twisted vascular pedicle “Whirlpool sign”

Color Doppler Imaging

•Color Doppler flow manifestations of ovarian torsion are highly variable and are based, mainly on the degree of vascular compromise.

•Color Doppler is targeted at the intraovarian blood vessels rather than the ovarian artery itself.

Normal Luteal color and pulsed wave Doppler flow

Color Doppler in ovarian torsion•A decrease in the Arterial blood and most

commonly the venous blood flow concomitantly.

•The most common feature though is a decrease or absence of venous blood flow, which is explained by the early collapse of their more compliant wall.

Is color Doppler Diagnostic?

•It can aid only if NO flow is detected

•If flow is detected its diagnostic value decreases with a better value in determining ovarian tissue viability increasing chances of ovarian Salvage.

•Presence of flow DOES NOT out rule torsion with possible explanations:

•1- Venous thrombosis from torsion may occur earlier than arterial thrombosis causing the emergence of symptoms with presence of flow.

•2- Dual ovarian blood supply•3- Intermittent torsion•4- Lack of confining ovarian capsule

ISUOG Classification of Adenxal torsion according to Gray scale and Doppler Ultrasound(2009)

•Class 1: Coiling of the vascular pedicle with detectable arterial and venous intraovarian flow; this Doppler profile is typically associated with a normal or mildly enlarged ovary, little or no peritoneal fluid, a lack of necrosis and favorable outcome.

•Class 2: Coiling of the ovarian vessels with detectable arterial blood flow but no venous flow within the ovary; this profile is typically associated with enlarged edematous ovaries, increased intrafollicular distance, follicular halos, mild to moderate free peritoneal fluid and intermediate outcome in terms of ovarian viability.

•Class 3, coiling with absent intraovarian arterial and venous flow, this situation is typically associated with an ischemic or necrotic ovary.

Pitfalls and mimicsHemorrhagic ovarian cysts are called “the great imitator” owing to their multiple appearancesdepending on the age of the blood, Common stages of bleeding are active hemorrhage,which appears anechoic at sonography, clotformation, retraction, and resolution.

A twisted hyperstimulated ovary can be distinguished from the normal by the separation of the cystic elements by marked stromal swelling in the torsed ovary

Computed Tomography (CT)

•Common CT findings are somewhat nonspecific and include an adnexal mass that may be in the midline, rotated toward the contralateral side of the pelvis deviation of the uterus to the side of the affected ovary and ascites.

Magnetic Resonance Imaging (MRI)•Common, nonspecific findings such as

deviation of the uterus and engorged blood vessels on the twisted side, pelvic ascites,and obliteration of fat planes.

Thank you