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CT and MR Imaging Features of Adnexal Torsion¹

¹ From the Department of Radiology, College of Medicine, Catholic University of Korea, 505 Banpo-Dong, Seocho-Ku, Seoul 137-040, South Korea. Presented as an education exhibit at the 2000 RSNA scientific assembly. Received March 14, 2001; revision requested June 5 and received July 24; accepted July 25. Address correspondence to J.Y.B. (e-mail: jybyun@cmc.cuk.ac.kr).

	Abstract

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
In adnexal torsion, the ovary, ipsilateral fallopian tube, or both twist with the vascular pedicle, resulting in vascular compromise. Unrelieved torsion is likely to cause hemorrhagic infarction as the degree of arterial occlusion increases. Therefore, early diagnosis is important to preserve the affected ovary. Adnexal torsion commonly accompanies an ipsilateral ovarian neoplasm or cyst but can also occur in normal ovaries, usually in children. Although ultrasonography is typically the initial emergent examination, computed tomography (CT) and magnetic resonance (MR) imaging may also be useful diagnostic tools. Common CT and MR imaging features of adnexal torsion include fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, ascites, and uterine deviation to the twisted side. Uncommon imaging findings in adnexal torsion that are specific to hemorrhagic infarction include hemorrhage in the thickened fallopian tube, hemorrhage within the twisted ovarian mass, and hemoperitoneum. Additional imaging findings that can suggest hemorrhagic infarction include eccentric smooth wall thickening exceeding 10 mm in a cystic ovarian mass converging on the thickened fallopian tube and lack of contrast enhancement of the internal solid component or thickened wall of the twisted ovarian mass. Early diagnosis can help prevent irreversible structural damage and may allow conservative, ovary-sparing treatment.

© RSNA, 2002

Index Terms: Fallopian tubes, CT, 853.1211 • Fallopian tubes, MR, 853.1214 • Fallopian tubes, torsion, 853.1437 • Ovary, CT, 852.1211 • Ovary, torsion, 852.1437 • Uterus, hemorrhage

	LEARNING OBJECTIVES FOR TEST 4

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
After reading this article and taking the test, the reader will be able to:

• Recognize the common and uncommon CT and MR imaging features of adnexal torsion.
  
• Recognize the typical imaging features of hemorrhagic infarction following adnexal torsion.
  

	Introduction

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
Adnexal torsion is an uncommon but serious cause of lower abdominal pain in women and is often difficult to distinguish from other acute abdominal conditions. However, the possibility of adnexal torsion should be considered when an ovarian mass is discovered in the appropriate clinical setting. Adnexal torsion is frequently associated with an ipsilateral ovarian tumor or cyst (50%–81% of cases) (1,2). However, it can also occur in normal ovaries, usually in children (3–5). If the adnexal torsion is complete and goes undiagnosed and untreated, hemorrhagic infarction may occur in the involved ovary and may lead to peritonitis and death (1). Early diagnosis can help prevent irreversible damage to the adnexal structures and may thus allow conservative, ovary-sparing treatment in young women. However, adnexal torsion occasionally presents a diagnostic dilemma, largely because of the related but nonspecific clinical, laboratory, and imaging findings (6). Although gray-scale ultrasonography (US) and color Doppler US have been reported to be useful in detecting adnexal torsion (7,8), computed tomography (CT) and magnetic resonance (MR) imaging may also be useful in making the preoperative diagnosis of adnexal torsion, especially in subacute cases.

In this article, we discuss and illustrate the common and uncommon CT and MR imaging features of adnexal torsion. We also present findings that can help determine the presence of hemorrhagic infarction in patients with adnexal torsion.

	Materials and Methods

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
Patients and Procedures
We retrospectively reviewed the clinical findings and the CT and MR imaging findings in 25 patients (age range, 5–85 years; mean, 40 years) with surgically proved adnexal torsion. All 25 patients complained of lower abdominal pain, with acute onset in 20 patients and gradual onset in the remaining five patients. The interval between the initial onset of symptoms and CT or MR imaging ranged from 1 day to 2 months (mean, 6 days), and the interval between imaging and surgery ranged from 1 to 9 days (mean, 2 days). CT alone was performed in 19 patients, MR imaging alone was performed in five patients, and both modalities were performed in one patient.

CT was performed with the commercially available Somatom Plus-S from Siemens (Erlangen, Germany) or 9800 scanner from GE Medical Systems (Milwaukee, Wis). Conventional CT was performed from the dome of the diaphragm to the symphysis pubis with a section collimation of 8–10 mm at 8–10-mm intervals. All patients underwent contrast material–enhanced CT, which was performed with intravenous administration of 120 mL of iopamidol (Iopamiro 300; Bracco, Milan, Italy) or iopromide (Ultravist 300; Schering, Berlin, Germany) at a rate of 1.5–3 mL/sec. Unenhanced CT was performed in five patients.

MR imaging was performed with a 1.5-T superconducting imager from GE Medical Systems (Signa Advantage) or Siemens (Magnetom Vision Plus) with a phased-array coil. T1-weighted MR imaging (repetition time msec/echo time msec = 400–600/11–19) was performed in all six patients, T2-weighted imaging (2,000–2,200/80–90) was performed in five patients, and axial and sagittal fast spin-echo imaging (3,000–3,200/85–99) was performed in one patient. Repeat T1-weighted images were obtained in the axial, sagittal and coronal planes after intravenous injection of 0.1 mmol/kg of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany). The field of view varied from 18.8 to 26.0 cm. Other imaging parameters were as follows: number of acquisitions, 2; matrix size, 256 x 192 for the Signa unit and 242 x 512 for the Magnetom unit; section thickness, 5 mm; and intersection gap, 1.5–2.5 mm.

Image Interpretation
All CT and MR imaging studies were reviewed retrospectively without reviewing the surgery or pathology reports. Our analysis of the imaging findings included evaluation of the fallopian tube (normal, thickened, hemorrhagic), adnexal mass (size, nature [cystic, solid, mixed], presence of wall thickening), and the presence of other peritoneal findings (ascites, hemoperitoneum, uterine deviation to the twisted side).

Fallopian Tube.— Tube thickening was determined to be present if any amorphous solid mass or targetlike appearance was noted around the adnexal mass. The tube was considered hemorrhagic if it had an attenuation greater than 50 HU on unenhanced CT scans or was hyperintense on both T1- and T2-weighted MR images.

Adnexal Mass.— In cases involving a cystic mass with a discernible wall, the presence and degree of wall thickening, the appearance of the thickened wall (smooth versus irregular, concentric versus eccentric), and the presence of hemorrhage within the mass or wall were also evaluated. Wall thickness was determined by measuring average thickness or the thickest portion if there was eccentric thickening. The cyst wall was considered thickened if it exceeded 3 mm. The presence of contrast enhancement in the internal septa, solid component, and thickened wall of the adnexal mass was evaluated at contrast-enhanced T1-weighted MR imaging.

Other Peritoneal Findings.— The amount of ascites was categorized as (a) none or trace, (b) small (ie, limited to the cul-de-sac and not extending over the pelvis), (c) moderate (ie, fluid around the liver, paracolic gutters, and pelvis), or (d) large (ie, additional fluid between the small bowel loops and colon). Hemoperitoneum was determined to be present if the attenuation of ascites exceeded 50 HU on unenhanced CT scans.

We compared the CT and MR imaging findings in adnexal torsion in patients with versus those without hemorrhagic infarction in terms of the presence of tube thickening, size of the twisted ovarian mass, wall thickness of the twisted ovarian mass, and presence of ascites and uterine deviation using the Student t test and the Fisher exact two-tailed test. A P value of less than .05 was defined as statistically significant.

Surgical and Pathologic Findings
All 25 patients had an ipsilateral benign ovarian mass. One patient had bilateral ovarian masses with unilateral adnexal torsion. The final pathologic diagnoses included benign cystic teratomas (n = 10), benign unclassified hemorrhagic ovarian cysts (n = 10), serous cystadenomas (n = 3), and fibromas (n = 2). Hemorrhagic infarction of the twisted ovary and tube was present in 19 of 25 patients. Ipsilateral salpingo-oophorectomy was performed in all 25 patients. In addition, cyst enucleation of the contralateral ovary was performed in one patient with bilateral ovarian cystic teratomas, and partial omentectomy was performed in one patient due to inflammatory adhesion between the omentum and the twisted ovarian mass. Adnexal torsion occurred on the left side in 15 patients and on the right side in 10 patients.

	Results

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
Common Imaging Features
Common CT and MR imaging features of adnexal torsion included fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, ascites, and uterine deviation to the twisted side.

Tube Thickening.— On CT or MR images, the tube of the involved adnexa was considered significantly thickened in 21 of 25 patients. At CT, the thickened tube manifested as an amorphous or tubular masslike structure in 15 cases (Figs 1, 2) and had a targetlike appearance in two cases (Fig 3). At axial CT and MR imaging, it was seen between the twisted adnexal mass and the uterus. In six cases, the thickened tube extended to the adnexal mass, partially covering the periphery of the mass. In four cases, it appeared on sagittal MR images as a protrusion on the twisted side continuous with the uterus (Figs 4, 5a, 5b), whereas in two cases the thickened tube was detected on axial MR images (Fig 5c).

View larger version (141K): [in this window] [in a new window] [Download PPT slide]   Figure 1a.  Torsion of a serous cystadenoma of the left ovary with hemorrhagic infarction in a 70-year-old woman with a 3-day history of lower abdominal pain. (a) Contrast-enhanced CT scan shows a large, unilocular cystic mass. Eccentric smooth wall thickening (maximum wall thickness, 15 mm) is noted along the left lateral margin of the mass (arrows). (b) Contrast-enhanced CT scan obtained caudad to a shows an amorphous masslike structure (arrows) connecting the tumor (M) and the uterus (U). This finding represents a twisted vascular pedicle.

View larger version (127K): [in this window] [in a new window] [Download PPT slide]   Figure 1b.  Torsion of a serous cystadenoma of the left ovary with hemorrhagic infarction in a 70-year-old woman with a 3-day history of lower abdominal pain. (a) Contrast-enhanced CT scan shows a large, unilocular cystic mass. Eccentric smooth wall thickening (maximum wall thickness, 15 mm) is noted along the left lateral margin of the mass (arrows). (b) Contrast-enhanced CT scan obtained caudad to a shows an amorphous masslike structure (arrows) connecting the tumor (M) and the uterus (U). This finding represents a twisted vascular pedicle.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 2a.  Torsion of a benign left ovarian cyst (unclassified) without hemorrhagic infarction in a 43-year-old woman with a 9-day history of gradually increasing lower abdominal pain. (a) Contrast-enhanced CT scan shows a unilocular cystic mass with a mildly enhancing wall (arrows). (b) Contrast-enhanced CT scan obtained caudad to a shows a poorly enhanced masslike structure (arrows) connecting the ovarian cystic mass (M) and the uterus (U). This finding represents a twisted, thickened fallopian tube.

View larger version (113K): [in this window] [in a new window] [Download PPT slide]   Figure 2b.  Torsion of a benign left ovarian cyst (unclassified) without hemorrhagic infarction in a 43-year-old woman with a 9-day history of gradually increasing lower abdominal pain. (a) Contrast-enhanced CT scan shows a unilocular cystic mass with a mildly enhancing wall (arrows). (b) Contrast-enhanced CT scan obtained caudad to a shows a poorly enhanced masslike structure (arrows) connecting the ovarian cystic mass (M) and the uterus (U). This finding represents a twisted, thickened fallopian tube.

View larger version (119K): [in this window] [in a new window] [Download PPT slide]   Figure 3a.  Torsion of a left ovarian fibroma with hemorrhagic necrosis in a 42-year-old woman with a 2-day history of lower abdominal pain. (a) Contrast-enhanced CT scan shows a well-circumscribed solid mass in the right lower abdomen (F). (b) Contrast-enhanced CT scan obtained caudad to a shows a whorled structure (arrows) abutting the inferior margin of the ovarian mass, a finding that represents a twisted vascular pedicle. A small amount of fluid (f) is also noted in the pelvic cavity. (c) Photograph of the surgical specimen demonstrates a dark brown, rubbery, ovoid solid ovarian mass with a twisted, thickened left fallopian tube (arrows). The torsion of the pedicle was 720°. The ovarian mass proved to be a fibroma with massive hemorrhagic infarction at surgery.

View larger version (128K): [in this window] [in a new window] [Download PPT slide]   Figure 3b.  Torsion of a left ovarian fibroma with hemorrhagic necrosis in a 42-year-old woman with a 2-day history of lower abdominal pain. (a) Contrast-enhanced CT scan shows a well-circumscribed solid mass in the right lower abdomen (F). (b) Contrast-enhanced CT scan obtained caudad to a shows a whorled structure (arrows) abutting the inferior margin of the ovarian mass, a finding that represents a twisted vascular pedicle. A small amount of fluid (f) is also noted in the pelvic cavity. (c) Photograph of the surgical specimen demonstrates a dark brown, rubbery, ovoid solid ovarian mass with a twisted, thickened left fallopian tube (arrows). The torsion of the pedicle was 720°. The ovarian mass proved to be a fibroma with massive hemorrhagic infarction at surgery.

View larger version (140K): [in this window] [in a new window] [Download PPT slide]   Figure 3c.  Torsion of a left ovarian fibroma with hemorrhagic necrosis in a 42-year-old woman with a 2-day history of lower abdominal pain. (a) Contrast-enhanced CT scan shows a well-circumscribed solid mass in the right lower abdomen (F). (b) Contrast-enhanced CT scan obtained caudad to a shows a whorled structure (arrows) abutting the inferior margin of the ovarian mass, a finding that represents a twisted vascular pedicle. A small amount of fluid (f) is also noted in the pelvic cavity. (c) Photograph of the surgical specimen demonstrates a dark brown, rubbery, ovoid solid ovarian mass with a twisted, thickened left fallopian tube (arrows). The torsion of the pedicle was 720°. The ovarian mass proved to be a fibroma with massive hemorrhagic infarction at surgery.

View larger version (165K): [in this window] [in a new window] [Download PPT slide]   Figure 4a.  Torsion of a cystic teratoma of the left ovary in a 41-year-old woman with bilateral benign cystic teratomas. (a) Coronal T1-weighted MR image shows two well-defined, bilateral ovarian masses (R = right mass, L = left mass) with heterogeneous signal intensity. (b, c) Right (b) and left (c) parasagittal contrast-enhanced fat-suppressed T1-weighted MR images demonstrate significant loss of signal intensity within the bilateral adnexal masses, a finding that suggests fat-containing masses (ie, teratomas). The lower portion of the right mass has a smooth, round configuration. In contrast, a beaklike protrusion is noted in the lower portion of the left mass (arrows in c), a finding that indicates a twisted pedicle. Note also the lack of contrast enhancement of the vascular pedicle. Surgery revealed a left cystic teratoma with a torsion of 280° and hemorrhagic infarction. U = uterus.

View larger version (157K): [in this window] [in a new window] [Download PPT slide]   Figure 4b.  Torsion of a cystic teratoma of the left ovary in a 41-year-old woman with bilateral benign cystic teratomas. (a) Coronal T1-weighted MR image shows two well-defined, bilateral ovarian masses (R = right mass, L = left mass) with heterogeneous signal intensity. (b, c) Right (b) and left (c) parasagittal contrast-enhanced fat-suppressed T1-weighted MR images demonstrate significant loss of signal intensity within the bilateral adnexal masses, a finding that suggests fat-containing masses (ie, teratomas). The lower portion of the right mass has a smooth, round configuration. In contrast, a beaklike protrusion is noted in the lower portion of the left mass (arrows in c), a finding that indicates a twisted pedicle. Note also the lack of contrast enhancement of the vascular pedicle. Surgery revealed a left cystic teratoma with a torsion of 280° and hemorrhagic infarction. U = uterus.

View larger version (154K): [in this window] [in a new window] [Download PPT slide]   Figure 4c.  Torsion of a cystic teratoma of the left ovary in a 41-year-old woman with bilateral benign cystic teratomas. (a) Coronal T1-weighted MR image shows two well-defined, bilateral ovarian masses (R = right mass, L = left mass) with heterogeneous signal intensity. (b, c) Right (b) and left (c) parasagittal contrast-enhanced fat-suppressed T1-weighted MR images demonstrate significant loss of signal intensity within the bilateral adnexal masses, a finding that suggests fat-containing masses (ie, teratomas). The lower portion of the right mass has a smooth, round configuration. In contrast, a beaklike protrusion is noted in the lower portion of the left mass (arrows in c), a finding that indicates a twisted pedicle. Note also the lack of contrast enhancement of the vascular pedicle. Surgery revealed a left cystic teratoma with a torsion of 280° and hemorrhagic infarction. U = uterus.

View larger version (169K): [in this window] [in a new window] [Download PPT slide]   Figure 5a.  Torsion of a serous cystadenoma of the right ovary with hemorrhagic necrosis in a 37-year-old woman with a 2-month history of recurrent lower abdominal pain. (a) Sagittal T2-weighted MR image shows a large, multiseptated cystic tumor with a beaklike protrusion inferiorly (arrows). (b) Sagittal contrast-enhanced fat-suppressed T1-weighted MR image shows linear peripheral tumor enhancement but lack of enhancement of the internal septa (arrowheads) and vascular pedicle (arrows). (c) Axial T1-weighted MR image shows a masslike tubular structure abutting the inferior margin of the mass (arrowheads), a finding that suggests a thickened fallopian tube. f = fluid, U = uterus. (d) Photograph of the gross specimen shows a large, multiseptated cystic tumor with extensive hemorrhagic necrosis. At surgery, the pedicle (arrowheads) was found to have a torsion of 900° in a counterclockwise direction.

View larger version (149K): [in this window] [in a new window] [Download PPT slide]   Figure 5b.  Torsion of a serous cystadenoma of the right ovary with hemorrhagic necrosis in a 37-year-old woman with a 2-month history of recurrent lower abdominal pain. (a) Sagittal T2-weighted MR image shows a large, multiseptated cystic tumor with a beaklike protrusion inferiorly (arrows). (b) Sagittal contrast-enhanced fat-suppressed T1-weighted MR image shows linear peripheral tumor enhancement but lack of enhancement of the internal septa (arrowheads) and vascular pedicle (arrows). (c) Axial T1-weighted MR image shows a masslike tubular structure abutting the inferior margin of the mass (arrowheads), a finding that suggests a thickened fallopian tube. f = fluid, U = uterus. (d) Photograph of the gross specimen shows a large, multiseptated cystic tumor with extensive hemorrhagic necrosis. At surgery, the pedicle (arrowheads) was found to have a torsion of 900° in a counterclockwise direction.

View larger version (123K): [in this window] [in a new window] [Download PPT slide]   Figure 5c.  Torsion of a serous cystadenoma of the right ovary with hemorrhagic necrosis in a 37-year-old woman with a 2-month history of recurrent lower abdominal pain. (a) Sagittal T2-weighted MR image shows a large, multiseptated cystic tumor with a beaklike protrusion inferiorly (arrows). (b) Sagittal contrast-enhanced fat-suppressed T1-weighted MR image shows linear peripheral tumor enhancement but lack of enhancement of the internal septa (arrowheads) and vascular pedicle (arrows). (c) Axial T1-weighted MR image shows a masslike tubular structure abutting the inferior margin of the mass (arrowheads), a finding that suggests a thickened fallopian tube. f = fluid, U = uterus. (d) Photograph of the gross specimen shows a large, multiseptated cystic tumor with extensive hemorrhagic necrosis. At surgery, the pedicle (arrowheads) was found to have a torsion of 900° in a counterclockwise direction.

View larger version (111K): [in this window] [in a new window] [Download PPT slide]   Figure 5d.  Torsion of a serous cystadenoma of the right ovary with hemorrhagic necrosis in a 37-year-old woman with a 2-month history of recurrent lower abdominal pain. (a) Sagittal T2-weighted MR image shows a large, multiseptated cystic tumor with a beaklike protrusion inferiorly (arrows). (b) Sagittal contrast-enhanced fat-suppressed T1-weighted MR image shows linear peripheral tumor enhancement but lack of enhancement of the internal septa (arrowheads) and vascular pedicle (arrows). (c) Axial T1-weighted MR image shows a masslike tubular structure abutting the inferior margin of the mass (arrowheads), a finding that suggests a thickened fallopian tube. f = fluid, U = uterus. (d) Photograph of the gross specimen shows a large, multiseptated cystic tumor with extensive hemorrhagic necrosis. At surgery, the pedicle (arrowheads) was found to have a torsion of 900° in a counterclockwise direction.

View larger version (126K): [in this window] [in a new window] [Download PPT slide]   Figure 6.  Torsion of a benign left ovarian cyst (unclassified) with hemorrhagic infarction in a 55-year-old woman with a 3-day history of lower abdominal pain. Contrast-enhanced CT scan shows a unilocular cystic mass (C) with eccentric smooth wall thickening along the anterior aspect (arrows). Note the anterior displacement of the uterus (U) by the cystic mass.

View larger version (137K): [in this window] [in a new window] [Download PPT slide]   Figure 7a.  Torsion of a right ovarian dermoid cyst with hemorrhagic infarction in a 5-year-old girl with a 24-hour history of lower abdominal pain. Axial unenhanced (a) and contrast-enhanced (b) T1-weighted MR images show a mass with eccentric smooth wall thickening along the left lateral margin (arrows). Mild wall enhancement is noted in b. Surgery revealed a right ovarian dermoid cyst with necrosis and a torsion of 720°.

View larger version (148K): [in this window] [in a new window] [Download PPT slide]   Figure 7b.  Torsion of a right ovarian dermoid cyst with hemorrhagic infarction in a 5-year-old girl with a 24-hour history of lower abdominal pain. Axial unenhanced (a) and contrast-enhanced (b) T1-weighted MR images show a mass with eccentric smooth wall thickening along the left lateral margin (arrows). Mild wall enhancement is noted in b. Surgery revealed a right ovarian dermoid cyst with necrosis and a torsion of 720°.

View larger version (124K): [in this window] [in a new window] [Download PPT slide]   Figure 8a.  Torsion of a benign right ovarian cyst (unclassified) with hemorrhagic infarction in a 7-year-old girl with a 2-month history of intermittent lower abdominal pain. (a) Axial T2-weighted MR image shows a thin-walled unilocular cyst with internal heterogeneous signal intensity (arrows). A twisted pedicle (arrowheads) is noted along the anterior aspect of the cystic mass. (b) Axial T1-weighted MR image shows an intermediate-signal-intensity mass with a hyperintense wall (arrows), a finding that suggests hemorrhage in the wall. Arrowheads indicate the twisted pedicle. (c) On an axial contrast-enhanced fat-suppressed T1-weighted MR image, the hemorrhagic mass (arrows) and the twisted pedicle (arrowheads) demonstrate no significant contrast enhancement. Surgery revealed a right ovarian cyst filled with reddish-brown hemorrhagic fluid and having a torsion of 900° in a clockwise direction.

View larger version (126K): [in this window] [in a new window] [Download PPT slide]   Figure 8b.  Torsion of a benign right ovarian cyst (unclassified) with hemorrhagic infarction in a 7-year-old girl with a 2-month history of intermittent lower abdominal pain. (a) Axial T2-weighted MR image shows a thin-walled unilocular cyst with internal heterogeneous signal intensity (arrows). A twisted pedicle (arrowheads) is noted along the anterior aspect of the cystic mass. (b) Axial T1-weighted MR image shows an intermediate-signal-intensity mass with a hyperintense wall (arrows), a finding that suggests hemorrhage in the wall. Arrowheads indicate the twisted pedicle. (c) On an axial contrast-enhanced fat-suppressed T1-weighted MR image, the hemorrhagic mass (arrows) and the twisted pedicle (arrowheads) demonstrate no significant contrast enhancement. Surgery revealed a right ovarian cyst filled with reddish-brown hemorrhagic fluid and having a torsion of 900° in a clockwise direction.

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 8c.  Torsion of a benign right ovarian cyst (unclassified) with hemorrhagic infarction in a 7-year-old girl with a 2-month history of intermittent lower abdominal pain. (a) Axial T2-weighted MR image shows a thin-walled unilocular cyst with internal heterogeneous signal intensity (arrows). A twisted pedicle (arrowheads) is noted along the anterior aspect of the cystic mass. (b) Axial T1-weighted MR image shows an intermediate-signal-intensity mass with a hyperintense wall (arrows), a finding that suggests hemorrhage in the wall. Arrowheads indicate the twisted pedicle. (c) On an axial contrast-enhanced fat-suppressed T1-weighted MR image, the hemorrhagic mass (arrows) and the twisted pedicle (arrowheads) demonstrate no significant contrast enhancement. Surgery revealed a right ovarian cyst filled with reddish-brown hemorrhagic fluid and having a torsion of 900° in a clockwise direction.

View larger version (124K): [in this window] [in a new window] [Download PPT slide]   Figure 9.  Torsion of a left ovarian cyst with hemorrhagic infarction in an 85-year-old woman. Contrast-enhanced CT scan shows a high-attenuation fluid collection in the Douglas pouch (arrows), a finding that suggests hemoperitoneum. M = twisted ovarian cyst, U = uterus.

View larger version (112K): [in this window] [in a new window] [Download PPT slide]   Figure 10a.  Torsion of a left ovarian dermoid cyst with hemorrhagic infarction in a 57-year-old woman. (a) Unenhanced CT scan shows a large mass (M) with a fat-fluid level and focal wall calcification. Note also the ill-defined tubular structure adhering to the cyst wall (arrowheads). This structure had an attenuation of about 64.3 HU, a finding that suggested a tubal hemorrhage. U = uterus. (b) Unenhanced CT scan shows the uterus deviated to the twisted side. Note the hazy fatty infiltration (arrows) around the twisted tumor (M) and fallopian tube.

View larger version (116K): [in this window] [in a new window] [Download PPT slide]   Figure 10b.  Torsion of a left ovarian dermoid cyst with hemorrhagic infarction in a 57-year-old woman. (a) Unenhanced CT scan shows a large mass (M) with a fat-fluid level and focal wall calcification. Note also the ill-defined tubular structure adhering to the cyst wall (arrowheads). This structure had an attenuation of about 64.3 HU, a finding that suggested a tubal hemorrhage. U = uterus. (b) Unenhanced CT scan shows the uterus deviated to the twisted side. Note the hazy fatty infiltration (arrows) around the twisted tumor (M) and fallopian tube.

Although only a small number of patients were included in our study, among the five patients who underwent unenhanced CT, hemorrhage in the fallopian tube was present in three (Fig 10). Among the six patients who underwent MR imaging, hemorrhage in the tube was present in one (Fig 11) and hemorrhage in the wall of the cystic mass was present in one (Fig 8). All four patients with hemorrhagic tube had adnexal torsion with hemorrhagic infarction. In the patient with twisted ovarian serous cystadenoma resulting in hemorrhagic infarction, lack of enhancement in the multiple internal septa of the tumor was noted on contrast-enhanced T1-weighted MR images (Fig 5).

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 11a.  Torsion of a right ovarian cyst with hemorrhagic infarction in a 40-year-old woman. Axial T2-weighted (a) and T1-weighted (b) MR images demonstrate an elongated masslike pedicle (arrowheads in a, black arrowheads in b) in the posterocaudal portion of a cystic mass (M). Focal high signal intensity is noted in b (white arrowheads), a finding that suggests a hemorrhagic right fallopian tube.

View larger version (135K): [in this window] [in a new window] [Download PPT slide]   Figure 11b.  Torsion of a right ovarian cyst with hemorrhagic infarction in a 40-year-old woman. Axial T2-weighted (a) and T1-weighted (b) MR images demonstrate an elongated masslike pedicle (arrowheads in a, black arrowheads in b) in the posterocaudal portion of a cystic mass (M). Focal high signal intensity is noted in b (white arrowheads), a finding that suggests a hemorrhagic right fallopian tube.

	Discussion

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

Adnexal torsion is generally unilateral, with a slight (3:2) right-sided predilection; this may be the result of the colon occupying pelvic space on the left or of hypermobility of the cecum and distal ileum on the right (1). In our study, however, there was a similar predilection for the left side whose cause could not be clearly determined.

Torsion of the ovarian pedicle produces circulatory stasis that is initially venous but becomes arterial as the torsion and resultant edema progress. If the torsion is complete and obstructs the arterial blood supply, gangrenous and hemorrhagic necrosis results. When complete torsion is suspected, immediate surgery is necessary to remove the damaged tissue (15). If left untreated, hemorrhagic infarction of the involved ovary may be followed by infection, leading to peritonitis and, in some cases, death. Local peritonitis may cause intestinal obstruction. If the torsion is partial and intermittent with spontaneous untwisting, symptoms may subside, only to return within hours, days, or weeks (1).

Early diagnosis and treatment may make it possible to conserve normal ovarian structures by untwisting the pedicle and resecting the cysts or tumors. However, due to nonspecific clinical and laboratory findings, surgery is delayed in the majority of cases. The most common treatment for adnexal torsion has been adnexectomy without untwisting because of the fear of thromboembolism from a thrombosed vein of the twisted ovary, the possibility of retorsion, and the inability to determine the viability of the ovary. However, several studies have reported that untwisting the vascular pedicle can not only conserve ovarian function but also preserve fertility without thromboembolism after detorsion (16–19). There appears to be increasing evidence that conservative therapy for adnexal torsion does in fact preserve normal ovarian function in spite of the acute ischemic insult. Therefore, differentiation of hemorrhagic from nonhemorrhagic infarction following adnexal torsion is important for treatment planning, although the twisted ovary could not be saved in any of our patients.

US is usually the first examination performed in an emergency setting. However, US findings of adnexal torsion (including a cystic, solid, or complex mass with or without pelvic fluid, thickening of the wall, and cystic hemorrhage) are nonspecific. Rosado et al (8) showed the limited specificity of Doppler US by demonstrating normal adnexal arterial waveforms at Doppler US in three cases of proved adnexal torsion. There are several possible explanations for these findings. One is that persistent adnexal arterial flow is related to the dual ovarian blood supply (the ovarian artery from the aorta and the ovarian arterial branches from the uterine artery). Another is that venous thrombosis due to torsion leads to symptoms and ovarian necrosis before arterial thrombosis occurs. A recent study reported that identification of the twisted vascular pedicle ("whirlpool sign") at US might suggest adnexal torsion and that color Doppler US could be helpful in predicting the viability of the twisted adnexal structures by depicting arterial and venous flow within the twisted vascular pedicle (19). However, US is operator dependent and experience is still limited; thus, its role in the early diagnosis of adnexal torsion is not yet fully established. CT and MR imaging are still commonly used to evaluate lower abdominal pain and suspected pelvic masses.

In patients with symptoms of adnexal torsion, authors recommend the use of color Doppler US in acute cases and in patients with no pelvic mass. The use of CT or MR imaging is recommended to help detect the twisted vascular pedicle or thickened tube in subacute or chronic cases and in patients with a suspected pelvic mass. These latter two modalities may be more useful in detecting the general configuration of the twisted adnexal mass in the diagnosis of hemorrhagic infarction. MR imaging must include fat-suppressed T1-weighted sequences to help detect hemorrhage and contrast-enhanced fat-suppressed T1-weighted sequences to help detect the absence of vascular supply, a finding that suggests hemorrhagic infarction.

In our study, the common CT and MR findings in adnexal torsion included tube thickening (84% of cases), smooth wall thickening of the twisted ovarian cystic mass (76%), ascites (64%), and uterine deviation to the twisted side (36%). Less common findings included hemorrhage in the thickened tube (16% of cases), hemorrhage within the adnexal mass (8%), and hemoperitoneum (8%).

Tube Thickening
Tube thickening or a twisted vascular pedicle is thought to be the most specific imaging finding for adnexal torsion. Tube thickening is related to congestion and edema with or without hemorrhagic infarction of the tube. It also indicates a twisted edematous pedicle, which connects the lesion with the uterus and enveloped engorged blood vessels. According to various anatomic and pathologic studies, the normal fallopian tube does not exceed 4 mm in diameter at its isthmic portion, 8 mm at its ampullary portion, and 10 mm at the infundibulum (20–22). Therefore, the tube can be considered thickened when its diameter exceeds 10 mm. Thickened tubes vary in appearance. They may manifest as an amorphous, solid masslike structure, have a targetlike appearance, or manifest as a beaklike protrusion extending from the uterus and partially covering the adnexal mass. Sagittal MR imaging in particular may be helpful in detecting tube thickening, which may manifest as a tubular protrusion from the superiorly located adnexal mass toward the inferiorly located uterus. This is because, in most cases, the lower pelvic cavity is too small to contain a twisted adnexal mass.

Smooth Mass Wall Thickening
All patients in our study had ipsilateral adnexal masses; 23 patients had cystic ovarian masses, and two patients had ovarian fibromas. Smooth wall thickening of the twisted cystic ovarian mass was a common imaging finding in adnexal torsion. Furthermore, eccentric smooth wall thickening of more than 10 mm was noted only in torsion with hemorrhagic infarction, not in torsion without hemorrhagic infarction. Although pathologic correlation was not established in each case, eccentric wall thickening of a cystic mass is presumed to be due to the edematous wall congestion in the ovarian cyst or to the thickened tube draped over the ovarian mass. Wall thickening of an adnexal cystic mass may be seen in a malignant tumor, but eccentric smooth wall thickening converging on the thickened tube can be the determining factor in making the diagnosis of a twisted adnexal mass with hemorrhagic infarction.

Ascites and Uterine Deviation
A small amount of ascites and uterine deviation to the twisted side were commonly seen on CT and MR images of adnexal torsion. However, although these findings may be helpful, they are not specific for adnexal torsion.

Other Findings
In addition to the eccentric wall thickening of adnexal cystic masses, imaging findings such as hemorrhagic tube, hemorrhage within the twisted ovarian mass, and hemoperitoneum were noted only in torsion with hemorrhagic infarction. At CT, hemorrhage can be diagnosed when its attenuation on unenhanced scans exceeds 50 HU. At MR imaging, hemorrhage can easily be diagnosed with fat-suppressed T1-weighted images. A high-signal-intensity tumor on fat-suppressed T1-weighted MR images suggests hemorrhage or vascular congestion. Although hemoperitoneum and hemorrhage within the ovarian mass can be noted in other acute gynecologic diseases (eg, hemorrhagic ovarian cyst, endometriosis with rupture, ectopic pregnancy [23]), we think these findings combined with tube thickening or a twisted vascular pedicle can suggest hemorrhagic infarction following adnexal torsion.

Other MR imaging findings that indicate this pathologic condition include lack of enhancement of the solid component, a thickened cyst wall, or a mural nodule of the twisted ovarian mass. These findings directly indicate interruption of blood flow and can lead to the diagnosis of adnexal torsion (24,25). Contrast-enhanced dynamic subtraction MR imaging in particular allows confirmation that the tumor is not enhanced. The intensity and extent of enhancement are clearly demonstrated on the subtraction image, even if the tumor has high signal intensity due to hemorrhage (23).

Our study has some limitations in that it was nonrandomized and retrospective. We could not determine the specificity and sensitivity of the previously described imaging findings in adnexal torsion because we included only those cases in which torsion was demonstrated at surgery. In addition, all of our patients underwent adnexectomy rather than conservative treatment; thus, it is unclear if the CT or MR imaging findings that suggest hemorrhagic infarction are sufficient to determine whether there is a chance of ovarian preservation.

	Conclusions

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 
Detection of tube thickening and of smooth wall thickening of an adnexal cystic mass at CT and MR imaging is useful in the diagnosis of a twisted ovarian mass. Sagittal MR imaging may be more helpful in detecting a thickened tube, which may be visualized as a tubular protrusion on the twisted side. Additional imaging findings that can suggest hemorrhagic infarction following adnexal torsion include eccentric smooth wall thickening exceeding 10 mm in a cystic ovarian mass converging on the thickened tube, lack of contrast enhancement of the internal solid component or the thickened wall of a twisted ovarian mass, hemorrhage within the tube or twisted ovarian mass, and hemoperitoneum.

	Acknowledgments

 
We thank Bonnie Hami, MA, Department of Radiology, University Hospitals of Cleveland, Ohio, for her editorial assistance in the preparation of the manuscript.

	References

Top Abstract LEARNING OBJECTIVES FOR TEST... Introduction Materials and Methods Results Discussion Conclusions References

 

1. Nichols DH, Julian PJ. Torsion of the adnexa. Clin Obstet Gynecol 1985; 28:375-380.[Medline]
2. Warner MA, Fleischer AC, Edell SL, et al. Uterine adnexal torsion: sonographic findings. Radiology 1985; 154:773-775.[Abstract/Free Full Text]
3. Hibbard LT. Adnexal torsion. Am J Obstet Gynecol 1985; 152:456-461.[Medline]
4. Lomano JM, Trelford JD, Ullery JC. Torsion of the uterine adnexa causing an acute abdomen. Obstet Gynecol 1970; 35:221-225.[Abstract/Free Full Text]
5. James DF, Barber HR, Graber EA. Torsion of normal uterine adnexa in children: report of three cases. Obstet Gynecol 1970; 35:226-230.[Abstract/Free Full Text]
6. Kimura I, Togashi K, Kawakami S, Takakura K, Mori T, Konishi J. Ovarian torsion: CT and MR imaging appearances. Radiology 1994; 190:337-341.[Abstract/Free Full Text]
7. Graif M, Shalev J, Strauss S, Engelberg S, Mashiach S, Itzchak Y. Torsion of the ovary: sonographic features. AJR Am J Roentgenol 1984; 143:1331-1334.[Abstract/Free Full Text]
8. Rosado WM, Jr, Trambert MA, Gosink BB, Pretorious DH. Adnexal torsion: diagnosis by using Doppler sonography. AJR Am J Roentgenol 1992; 159:1251-1253.[Free Full Text]
9. Peterson WF, Prevost EC, Edmunds FT, Hundley JM, Morris FK. Benign cystic teratomas of the ovary: a clinico-statistical study of 1,007 cases with a review of the literature. Am J Obstet Gynecol 1955; 70:368-382.
10. Caruso PA, Marsh MR, Minkowitz S, Karten G. An intense clinico-pathologic study of 305 teratomas of the ovary. Cancer 1971; 27:343-348.[CrossRef][Medline]
11. Pantoja E, Noy MA, Axtmayer RW, Colon FE, Pelegrina I. Ovarian dermoids and their complications: comprehensive historical review. Obstet Gynecol Surv 1975; 30:1-20.[Medline]
12. Comerci JT, Jr, Licciardi F, Bergh PA, Gregori C, Breen JL. Mature cystic teratoma: a clinicopathologic evaluation of 517 cases and review of the literature. Obstet Gynecol 1994; 84:22-28.[Abstract/Free Full Text]
13. Graif M, Itzchak Y. Sonographic evaluation of ovarian torsion in childhood and adolescence. AJR Am J Roentgenol 1988; 150:647-649.[Abstract/Free Full Text]
14. Kim YH, Cho KS, Ha HK, et al. CT features of torsion of benign cystic teratoma of the ovary. J Comput Assist Tomogr 1999; 23:923-928.[CrossRef][Medline]
15. DiSaia PJ. Ovarian disorders. In: Scott JR, DiSaia PJ, Hammond CB, Spellacy WN, eds. Danforth’s obstetrics and gynecology. 6th ed. Philadelphia, Pa: Lippincott, 1990; 1067-1120.
16. Bayer AI, Wiskind AK. Adnexal torsion: can the adnexa be saved?. Am J Obstet Gynecol 1994; 171:1506-1510.[Medline]
17. Wagaman R, Williams RS. Conservative therapy for adnexal torsion: a case report. J Reprod Med 1990; 35:833-834.[Medline]
18. Ben-Rafael Z, Bider D, Mashiach S. Laparoscopic unwinding of twisted ischemic hemorrhagic adnexum after in vitro fertilization. Fertil Steril 1990; 53:569-571.[Medline]
19. 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 1998; 17:83-89.[Abstract]
20. Wheeler JE. Diseases of the fallopian tube. In: Kurman RJ, eds. Blaustein’s pathology of the female genital tract. New York, NY: Springer-Verlag, 1987; 409-413.
21. Rouviere H, ed. Anatomie humaine Paris, France: Masson, 1940.
22. Ghossain MA, Buy JN, Bazot M, et al. CT in adnexal torsion with emphasis on tubal findings: correlation with US. J Comput Assist Tomogr 1994; 18:619-625.[Medline]
23. Dohke M, Watanabe Y, Okumura A, et al. Comprehensive MR imaging of acute gynecologic diseases. RadioGraphics 2000; 20:1551-1566.[Abstract/Free Full Text]
24. Outwater EK, Dunton CJ. Imaging of the ovary and adnexa: clinical issues and applications of MR imaging. Radiology 1995; 194:1-18.[Abstract/Free Full Text]
25. Outwater EK. Magnetic resonance imaging of acute and chronic pelvic pain disorders. In: Fleischer AC, Javitt MC, Jeffrey RB, Jones HW, eds. Clinical gynecologic imaging. Philadelphia, Pa: Lippincott-Raven, 1997; 263-271.

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