AUTHOR AND EDITOR INFORMATION

Section 1 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

INTRODUCTION

Section 2 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

Background

In adnexal torsion, the ovary and fallopian tube are typically involved. This condition is usually associated with reduced venous return from the ovary as a result of stromal edema, hyperstimulation, or a mass; it requires a quick and confident diagnosis to save the adnexal structures from infarction. Ultrasonography with color Doppler analysis is the method of choice for the evaluation of adnexal torsion because it can show morphologic and physiologic changes in the ovary. Gray-scale and spectral findings are correlated with the age of the torsion (ie, acute torsion or chronic torsion) and the degree of the twist or torsion.

Related Medscape topics:
Resource Center Ovarian Cancer
Fallopian Tube Torsion
Diagnosing and Managing Adnexal Masses

Related eMedicine topics:
Ovarian Torsion: Emergency Medicine
Ovarian Cysts
Adnexal Tumors

Pathophysiology

Adnexal torsion may develop without a definitive etiology. It often occurs as a result of increased weight of the ovary; this may be caused by reduced venous return from the ovary of unknown cause or by an actual ovarian and/or adnexal mass, with torsion of the ovary or torsion of the ovary and fallopian tube. The torsion itself further reduces venous return from the ovary. Greater degrees of adnexal torsion reduce arterial flow within the ovary as well, although flow within the vascular pedicle usually continues. Hemorrhagic infarction within the ovary may occur when the torsion is persistent or chronic.

Frequency

United States

Adnexal torsion accounts for an estimated 3% of surgical gynecologic emergencies. Approximately 50-60% of cases of torsion are associated with an adnexal mass.

Mortality/Morbidity

• Mortality resulting from torsion is rare. Cases in which pulmonary emboli result from thrombi in the pelvic veins have been reported in patients with ovarian torsion, adnexal torsion, or both.
• Morbidity usually arises from the pain associated with torsion. The adnexa may become gangrenous with chronic torsion.

Age

Two groups of women tend to be affected by adnexal torsion: (1) women in their mid 20s and (2) women who are postmenopausal. Approximately 20% of the cases of torsion occur during pregnancy.^{1, 2} Women with an adnexal mass who are postmenopausal may also be affected. Adolescents are also at risk; this may be because of changes in the weight of their maturing adnexa.²

Anatomy

The ovary has a dual arterial and venous blood supply. The arterial supply is derived from the ovarian arteries that branch from the abdominal aorta, as well as from the adnexal branches of the uterine artery. The venous system parallels the arterial, with the exceptions that the left ovarian vein empties into the left renal vein and that the right ovarian vein courses into the inferior vena cava. The fallopian tubes are fed and are drained by means of vessels that anastomose with ovarian branches derived from uterine vessels in the mesosalpinx.

Clinical Details

Confident and early diagnosis of adnexal torsion is imperative. Color Doppler sonography has a vital role in the examination of women with lower abdominal and pelvic pain.^{3, 4}

The signs and symptoms associated with torsion are variable and nonspecific. Most patients present with severe lower abdominal and pelvic pain, nausea, and vomiting.⁵ The differential diagnosis to be considered at clinical examination include appendicitis, gastroenteritis, ectopic pregnancy, pelvic inflammatory disease, and ruptured corpus luteum. Among adolescents, hemorrhagic ovarian cysts must also be considered. Laboratory tests are not helpful, because most signs and symptoms of ovarian torsion can be associated with leukocytosis.

Preferred Examination

Diagnostic sonography should be the first examination performed; typically, the affected ovary is enlarged, with multiple immature or small follicles along its periphery. Color Doppler sonography can help in determining whether blood flow is impaired.^{4, 6, 7, 8} Rarely, computed tomography (CT) or magnetic resonance imaging (MRI) is needed to make a definitive diagnosis. CT or MRI can serve as a secondary modality when ultrasonographic findings are nondiagnostic.^{9, 10, 11}

Limitations of Techniques

Although a lack of intraovarian arterial and venous flow enables confident diagnosis, torsion may be incomplete; incomplete torsion may be associated with adnexal flow, as depicted with color Doppler sonography. Rarely, the use of improper settings can cause erroneous findings of absent flow. Check that the proper settings are used by looking for flow in the internal iliac vein.

In some cases, flow depiction may be difficult to obtain from the affected ovary, as well as the healthy contralateral ovary. In these cases, the characteristic gray-scale morphologic image of ovarian torsion alone may help in making the diagnosis.

CT SCAN

Section 3 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

Findings

CT scans may demonstrate ovarian enlargement, small or immature peripheral follicles, and intraperitoneal fluid. In a study by Kimura et al, the following 3 findings were seen in patients with hemorrhagic infarction: (1) protrusion of the lesion on the twisted side; (2) thick, straight blood vessels draped around the lesion; and (3) complete absence of enhancement.^{9, 12}

MRI

Section 4 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

Findings

MRI may demonstrate ovarian enlargement and intraperitoneal fluid. In one case report, MRI demonstrated a twisted pedicle. If hemorrhagic infarction is present, MRI can demonstrate an enlarged ovary with displaced follicles. T2-weighted images show low signal intensity caused by interstitial hemorrhage, and T1-weighted images show a thin rim of high signal intensity without contrast enhancement.^{9, 11, 13, 14}

ULTRASOUND

Section 5 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

Findings

One of the most frequent findings on sonograms is ovarian enlargement. The ovary usually contains several immature follicles along its periphery. On color Doppler sonograms, no intraovarian venous flow is present; this finding is followed by a lack of intraovarian arterial flow. Flow within the adnexal vessels may be preserved.

Occasionally, the twisted pedicle of the affected ovary can be recognized. A twisted pedicle is a relatively specific sign for ovarian torsion. With isolated tubal torsion, the tube is usually distended and lacks flow or has reversed flow during diastole. Because venous flow is under low pressure, it is the first flow to be affected by the increased interstitial pressure of a twisted ovary. In chronic torsion, arterial waveforms can mimic venous waveforms. When torsion is complete, no arterial waveforms can be detected within the ovary.

Intraperitoneal fluid may surround the twisted ovary. This usually is the result of interstitial fluid that weeps of an affected ovary rather than a true rupture of the capsule and extrusion of blood.^{3, 4, 6, 7, 8}

Degree of Confidence

The presence of an enlarged ovary with lack of intraovarian arterial or venous flow is highly indicative of torsion, particularly if the typical appearance of an enlarged ovary with small peripheral cysts is depicted.^{4, 7} Do not be dissuaded from the diagnosis of this entity if flow is present in the adnexal vessels; this finding may indicate incomplete torsion.

False Positives/Negatives

Chronic tuboovarian abscesses and/or complexes may mimic torsion, particularly torsion with contained areas of infarction.

MULTIMEDIA

Section 6 of 7  

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

Media file 1:  Video depicts 2 findings: first, it shows an enlarged hypovascular left ovary; second, it shows flow in the healthy right ovary. A small amount of intraperitoneal fluid surrounds the left ovary.
	View Full Size Image
Media type:  Video

REFERENCES

Section 7 of 7

• Authors and Editors
• Introduction
• CT SCAN
• MRI
• Ultrasound
• Multimedia
• References

1. Bider D, Mashiach S, Dulitzky M, Kokia E, Lipitz S, Ben-Rafael Z. Clinical, surgical and pathologic findings of adnexal torsion in pregnant and nonpregnant women. Surg Gynecol Obstet. Nov 1991;173(5):363-6. [Medline].
2. Griffin D, Shiver SA. Unusual presentation of acute ovarian torsion in an adolescent. Am J Emerg Med. May 2008;26(4):520.e1-3. [Medline].
3. Fleischer AC, Brader KR. Sonographic depiction of ovarian vascularity and flow: current improvements and future applications. J Ultrasound Med. Mar 2001;20(3):241-50. [Medline].
4. Lee EJ, Kwon HC, Joo HJ, Suh JH, Fleischer AC. Diagnosis of ovarian torsion with color Doppler sonography: depiction of twisted vascular pedicle. J Ultrasound Med. Feb 1998;17(2):83-9. [Medline].
5. Shadinger LL, Andreotti RF, Kurian RL. Preoperative sonographic and clinical characteristics as predictors of ovarian torsion. J Ultrasound Med. Jan 2008;27(1):7-13. [Medline].
6. Fleischer AC, Stein SM, Cullinan JA, Warner MA. Color Doppler sonography of adnexal torsion. J Ultrasound Med. Jul 1995;14(7):523-8. [Medline].
7. Peña JE, Ufberg D, Cooney N, Denis AL. Usefulness of Doppler sonography in the diagnosis of ovarian torsion. Fertil Steril. May 2000;73(5):1047-50. [Medline].
8. Filho SM, Júnior EA, Serafini P, Filho HA, Pires CR, Nardozza LM, et al. Diagnosis of ovarian torsion by three-dimensional power Doppler in first trimester of pregnancy. J Obstet Gynaecol Res. Apr 2008;34(2):266-70. [Medline].
9. Kimura I, Togashi K, Kawakami S, Takakura K, Mori T, Konishi J. Ovarian torsion: CT and MR imaging appearances. Radiology. Feb 1994;190(2):337-41. [Medline].
10. Siegelman ES, Outwater EK. Tissue characterization in the female pelvis by means of MR imaging. Radiology. Jul 1999;212(1):5-18. [Medline].
11. Van Kerkhove F, Cannie M, Op de Beeck K, Timmerman D, Pienaar A, Smet MH, et al. Ovarian torsion in a premenarcheal girl: MRI findings. Abdom Imaging. May-Jun 2007;32(3):424-7. [Medline].
12. Gittleman AM, Price AP, Goffner L, Katz DS. Ovarian torsion: CT findings in a child. J Pediatr Surg. Aug 2004;39(8):1270-2. [Medline].
13. Kawakami K, Murata K, Kawaguchi N, Furukawa A, Morita R, Tenzaki T, et al. Hemorrhagic infarction of the diseased ovary: a common MR finding in two cases. Magn Reson Imaging. 1993;11(4):595-7. [Medline].
14. MacDuff R, Anthony GS, MacLennan AC. Ovarian torsion diagnosed by MRI. J Obstet Gynaecol. Oct 2007;27(7):743-4. [Medline].

Article Last Updated: Jun 23, 2008