1. science
2. medicine
3. surgery

Diagnosis of Ovarian Torsion with
Color Doppler Sonography:
Depiction of Twisted Vascular Pedicle
Eun Ju Lee, MD, Hyuck Chan Kwon, MD, Hee Jae Joo, MD, Jung Ho Suh, MD,
Arthur C. Fleischer, MD
The purpose of this study was to assess the diagnostic value of ultrasonography for the detection of
twisted vascular pedicle in ovarian torsion and to
verify whether the blood flow alterations in the
twisted vascular pedicle on color Doppler sonography can predict the viability of adnexal structures.
In 28 of 32 patients with surgically proved torsion,
the twisted vascular pedicle was detected preoperatively by ultrasonography, which shows a diagnostic accuracy of 87%. Arterial and venous flows
were present in the twisted vessels on color
Doppler sonography in 16 of 28 patients with a visible twisted vascular pedicle. In 11 patients who
underwent adnexectomy, the pathologic findings
I
n adnexal torsion, the ovary or ipsilateral fallopian tube, or both, twists with the vascular pedicle as the axis, resulting in arterial and venous
ABBREVIATIONS
CDS, Color Doppler sonography; TVS, Transvaginal sonography;
TV-CDS, Transvaginal color Doppler sonography
Received May 21, 1997, from the Departments of Radiology (E.J.L.,
J.H.S.), Obstetrics and Gynecology (H.C.K.), and Pathology (H.J.J.),
Ajou University, College of Medicine, Kyunggi-do, South Korea; and
the Department of Radiology (A.C.F.), Vanderbilt University Medical
Center, Nashville, TN. Revised manuscript accepted for publication
October 14, 1997.
Address correspondence and reprint requests to Eun Ju Lee, MD,
Department of Diagnostic Radiology, Ajou University Medical Center, San 5, Wonchon-dong, Paldal-gu, Suwon, Kyunggi-do, 442-749,
South Korea.
revealed nonnecrotic ovaries in 10 patients.
Untwisting of the twisted vascular pedicle was performed in five patients, and follow-up ultrasonography showed normal follicular development and
ovulation. All 12 patients who showed no blood
flow within the twisted vascular pedicle had
necrotic ovaries. In conclusion, identification of the
twisted vascular pedicle through ultrasonography
is suggestive of ovarian torsion, and color Doppler
sonography could be helpful in predicting the viability of adnexal structures by depicting blood flow
within the twisted vascular pedicle. KEY WORDS:
Ovary, torsion; Adnexa, torsion; Ovary, tumors;
Color Doppler sonography.
compromise. Unrelieved torsion is likely to be followed by hemorrhagic infarction as the degree of
arterial occlusion progresses. Therefore, early diagnosis of torsion can prevent irreversible damage to
the adnexal structures and may contribute to conservative treatment, which may spare the ovary in
young women. Ovarian torsion is frequently associated with an ipsilateral ovarian mass (50 to 81%),
which may act as fulcrum to potentiate torsion of
adnexa due to increased ovarian volume or intraabdominal pressure.1,2
Adnexal torsion is often difficult to distinguish
from other acute abdominal conditions; however, the
possibility of ovarian torsion should be considered
when an ovarian mass is discovered in the appropriate clinical setting. The variable sonographic findings of the twisted ovary including a solid, cystic,
and complex mass with free fluid, diffusely enlarged
ovary containing one or more large cystic follicles at
the periphery, and marked thickening of the cyst
 1998 by the American Institute of Ultrasound in Medicine • J Ultrasound Med 17:83–89, 1998 • 0278-4297/98/$3.50
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OVARIAN TORSION: TWISTED VASCULAR PEDICLE
wall, have been described.3–5 However, these features
are nonspecific and focus on the twisted ovary itself,
which is not detectable in many cases, especially if
associated with an ovarian tumor. Therefore, these
findings cannot be used as diagnostic criteria in all
cases of ovarian torsion. The role of CDS in the early
diagnosis of ovarian torsion with depiction of an
enlarged ovary that has no demonstrable perfusion
in the parenchyma has been reported previously in
some cases, but it is still not fully established.6–8
The purposes of this study were to describe a
sonographic finding that may suggest the preoperative diagnosis of ovarian torsion, to assess the diagnostic value of ultrasonography for the depiction of
the twisted vascular pedicle in ovarian torsion, and
to verify whether the blood flow alteration in the
twisted vascular pedicle on CDS can predict the viability of the adnexal structures.
MATERIALS AND METHODS
For a period of 2 years, 47 patients who were admitted for acute or intermittent lower abdominal pain
with a palpable pelvic mass or previous history of
ovarian tumor were investigated with both ultrasonography and CDS for ovarian torsion. Sonography was performed transvaginally and
transabdominally with Ultramark 9-HDI system
(Advanced Technology Laboratories, Bothell, WA)
using a 2.0-4.0 MHz curved array or 5.0 MHz curved
array transvaginal probe in all patients with the
exception of four patients who were virginal or pregnant; these four were examined only transabdominally. To optimize the CDS images, the following
parameters were applied: spatial peak temporal
average intensity set at approximately 40 to 92
mW/cm2 and the wallfilter at 50 to 100 Hz, pulse
repetition frequencies between 2 and 10 kHz, and
velocity range lowered to 4 to 20 cm/sec. The
Doppler angle of insonation was less than 60
degrees. A minimum of three waveforms were
recorded from the twisted vessels within the twisted
vascular pedicle.
The patients ranged in age from 20 to 70 years
(mean, 32.1 years). The clinical findings, including
symptoms, history of associated pregnancy, and laboratory findings, were obtained from the patients’
medical records. We evaluated the presence of
twisted vascular pedicle in twisted ovaries by ultrasonography. Normally the vascular pedicle of the
ovary, which connects the ovary with uterus and
envelops the adnexa and ovarian branches of the
uterine artery and vein, appears to have a course that
J Ultrasound Med 17:83–89, 1998
may be either straight or tortuous of intrapedicular
blood vessels on ultrasonography and CDS. We
defined the twisted vascular pedicle as the rotation
site of the vascular pedicle of ovary. It was identified
either adjacent to the ovary or ovarian tumors or as a
structure visualized separately between the uterus
and ovary on the side of the twisted adnexa. Torsion
was excluded if we could not detect the twisted vascular pedicle or if the blood vessels within the vascular pedicle had a straight course. In cases in which
we could detect the twisted vascular pedicle, torsion
was diagnosed on the basis of this finding, and the
diagnostic accuracy of twisted vascular pedicle was
evaluated. The different morphologic characteristics
of the twisted vascular pedicle, including size, shape,
internal echogenicity, and visibility of internal vascular structures, were evaluated. The twisted vascular
pedicle was measured at its greatest diameter. Color
flow sonography and pulsed Doppler sonography
were performed to depict the presence or absence of
arterial and venous flow within the twisted vascular
pedicle and to verify alteration of flow patterns. We
considered the adnexal structure potentially viable if
blood flow within the twisted vascular pedicle was
present, and correlation with the pathologic findings
of the affected ovaries, tubes, and tumors was performed.
Ovarian torsion was confirmed at the time of
surgery in 32 patients. The degree of torsion was
determined and gross inspection of the affected
adnexal structures was carried out. Salpingooophorectomy and oophorectomy were performed
in 22 patients and five patients, respectively.
Untwisting of the twisted adnexa with cystectomy or
fluid aspiration was performed in the remaining five
patients. For those 15 patients whose ovaries were
not twisted, pathologic diagnosis of ovarian masses
revealed hemorrhagic cyst (follicular, corpus luteal,
lutein cyst) in 12 cases, endometrioid cyst in two
cases, and tuboovarian cyst in one case.
RESULTS
Of 32 patients with surgically confirmed ovarian torsion, 25 patients had lower abdominal pain. Acute
pelvic pain was present for a period of from 6 hours
to 2 days in 21 patients, and chronic intermittent pain
was present in four patients for up to 10 months
prior to admission. A palpable pelvic mass in 20
patients, tenderness on pelvic examination in 13
patients, and leukocytosis in seven patients were
noted. Thirteen patients had a past history of the
ovarian tumor and five patients were pregnant (9 to
J Ultrasound Med 17:83–89, 1998
13 weeks’ gestation). Surgery was performed within
48 hours after sonographic study in all patients. The
side of torsion was on the right in 15 patients and on
the left in 17 patients, and the degree of torsion was
ranged from 180 degrees (1/2 complete twist) to 2160
degrees (six complete twists). Pathologic diagnosis of
ovarian masses included teratoma in 15 cases, serous
and mucinous tumor in five cases (three cystadenoma, two borderline malignancy), endometrioid
carcinoma in one case, fibroma in one case, follicular
cyst in four cases, and corpus luteum cyst in five
cases.
At sonography, an ovarian mass was detected on
the side of torsion in all patients. The diameters of
the ovarian masses ranged from 5 to 33 cm; 17 cases
were mostly cystic masses and 15 cases were cystic
and solid masses. Twenty-two cases had free fluid in
the cul-de-sac. Only four cases had demonstrable
ovarian parenchyma on the affected side. In 28 of 32
patients with surgically proved torsion the twisted
vascular pedicle was detected preoperatively by
ultrasonography, showing a diagnostic accuracy of
87%. Two false-positive cases occurred in which the
ovaries were not twisted and in which the preoperative ultrasonograms showed the twisted vascular
pedicle. One case was a follicular cyst with subacute
salpingitis, and the other was a hemorrhagic corpus
luteum cyst with edematous salpinx. The sensitivity
and specificity of ultrasonography for the detection
of twisted vascular pedicle in ovarian torsion were
88% and 87%, respectively. The positive and negative
predictive values were 93% and 76%, respectively.
In the other four patients with ovarian torsion, the
twisted vascular pedicle was not visible on sonography. All four cases had 360 degrees of torsion or less
(one case with 180 degrees, three cases with 360
degrees). Only transabdominal sonography was performed in one virginal patient and one pregnant
patient. Of these false-negative cases, three were
malignant ovarian tumors, including two cases of
serous and mucinous tumor of borderline malignancy and one case of endometrioid carcinoma.
The shape and echogenicity of the sonographically
visible twisted vascular pedicle varied depending on
different views of the structure. The twisted vascular
pedicle appeared as a round echogenic mass with
multiple concentric hypoechoic stripes (target
appearance) in 11 cases, as a beaked appearance with
concentric hypoechoic stripes in five cases, or as an
ellipsoid or tubular mass with internal heterogeneous echoes in 12 cases. We were able to distinguish
the vascular structures within the twisted vascular
pedicle on gray scale image in 13 patients but not in
the other 15 patients. If the blood flow was present in
LEE ET AL
85
the twisted vessels within the twisted vascular
pedicle on CDS, the characteristic finding of circular or coiled twisted vessels, the so-called
“whirlpool sign,” was presented in 16 cases (Fig. 1).
Thirteen patients with blood flow seen on CDS and
the vascular structure identified on gray scale
sonography had either the target (n = 11) or the
beaked (n = 2) appearance, whereas three patients
with visible flow on CDS but no vascular structure
seen on gray scale sonography had either a beaked
appearance (n = 2) or an ellipsoid mass with heterogeneous echoes (n = 1). Thus, documentation of
these typical circular vessels on CDS helped to
identify the twisted vascular pedicle and to make
the diagnosis of torsion. The size of the twisted vascular pedicle ranged in diameter from 2 to 8 cm
(mean, 4.2 cm). In 15 cases of torsion of 360 degrees
(one complete twist) or less, the twisted vascular
pedicles were smaller in diameter, ranging between
2 and 4 cm, and had a target or beaked appearance
with identifiable vascular structures within the
pedicle. On the other hand, in 13 cases of torsion of
more than 360 degrees, the twisted vascular pedicles were large in diameter, ranging between 3.5
and 8 cm, and had a tubular or ellipsoid appearance
with heterogeneous echoes, and the vascular structures not identified within the pedicle.
In 16 of 28 patients with a visible twisted vascular pedicle, arterial and venous flows were present
within the twisted vascular pedicle on CDS. Eleven
patients underwent adnexectomy, and their pathologic findings showed normal ovary in six cases,
edema and early hemorrhage in each of two cases,
and hemorrhagic infarction in one case. One patient
with pathologically confirmed hemorrhagic infarction had absent end diastolic flow of arterial waveform (Fig. 2). In the remaining five patients whose
ovaries were considered potentially viable by preoperative CDS and by visual inspection at surgery,
untwisting of the twisted vascular pedicle was performed. Three of five patients, two with teratoma
and one with cystadenoma, were treated by cystectomy. In the remaining two patients with corpus
luteal cyst, only fluid aspiration was performed to
untwist the vascular pedicle. Subsequent follow-up
sonography and CDS performed 3 days to 8 weeks
after the detorsion procedure revealed the presence
of both arterial and venous flow as well as evidence
of normal follicular development and ovulation.
The remaining 12 patients showed no blood flow
within the twisted vascular pedicle on CDS, and all
of them demonstrated hemorrhagic infarction of the
adnexal structures (Fig. 3).
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OVARIAN TORSION: TWISTED VASCULAR PEDICLE
DISCUSSION
Ovarian torsion is caused by rotation of the ovary or
adnexa with the vascular pedicle on its axis, resulting
in arterial, venous, or lymphatic obstruction. It is an
acute condition that requires prompt surgical intervention to save the ovary. The ultrasonographic findings in ovarian torsion have been described as a
cystic, solid, or complex mass with or without pelvic
fluid, thickening of the wall, and cystic hemorrhage.
However, these findings are not specific for ovarian
torsion, and it is difficult to distinguish them from
the findings seen in the other disease, such as hemorrhagic cyst, endometriosis, pelvic inflammatory
disease, and ectopic pregnancy.1,2,4 Previous reports
suggested that the presence of multiple peripherally
located follicles in a case of unilateral enlarged ovary
J Ultrasound Med 17:83–89, 1998
might be the specific finding of ovarian torsion, but
this feature was not always observed.3–5 Moreover,
sonographic appearances of ovarian torsion are more
closely related to the duration and degree of torsion,
complete or incomplete, and the presence or absence
of an associated intraovarian mass or hemorrhage.8,9
The ovarian parenchyma was not identifiable in
many cases in our study, thereby making it more difficult to document the intraovarian flow as well as
making this ovarian finding less useful in the diagnosis of torsion associated with an ovarian tumor.
Although previous studies have focused exclusively on the ovary or the associated ovarian mass,
we placed more emphasis on the observation of the
twisted vascular pedicle of affected ovary, which corresponds to the broad ligament, fallopian tube, and
adnexal and ovarian branches of the uterine artery
Figure 1 27 year old patient with 360 degree torsion of the left ovary and teratoma at 9 weeks of gestation. A, TVS shows a 2 cm
round mass with a target appearance (arrows) adjacent to the ovarian tumor, indicating a twisted vascular pedicle. B, TV-CDS
shows circular vascular structures within the twisted vascular pedicle (“whirlpool” sign). C,D, Color Doppler flow velocimetry
demonstrates arterial (C) and venous (D) flow of the vascular structures within the twisted vascular pedicle. Pathologic examination revealed nonnecrotic ovary and tube.
A
B
C
D
J Ultrasound Med 17:83–89, 1998
and vein. The twisted vascular pedicle in ovarian torsion was identified by ultrasonography in 88% of the
cases of torsion. Therefore, the previously described
findings suggested that the presence of the twisted
vascular pedicle on ultrasonograms could be a valuable diagnostic sign of the ovarian torsion, with a
higher detection rate than the previously described
sonographic findings of the twisted ovary or the
ovarian masses; the detection rate of a cystic, solid, or
complex mass was between 46 and 74%, and that of
multiple peripherally located follicles in enlarged
ovary was 64%.2–4
The twisted vascular pedicle appeared as a round
hyperechoic structure with multiple concentric
hypoechoic stripes (target appearance), as a beaked
structure with concentric low echoic stripes, or as an
ellipsoid or tubular structure with internal heteroge-
LEE ET AL
87
neous echoes. Concentric low echoic intrapedicular
structures could be identified as vascular structures
by CDS (“whirlpool sign”), and this finding might be
useful in the diagnosis of ovarian torsion. Although
the detection of the twisted vascular pedicle was difficult when no blood flow was present in the intrapedicular vessels, in our experience it was not
impossible to detect the twisted vascular pedicle in
this condition.
In cases with a relatively small twisted vascular
pedicle and torsion of less than 360 degrees, technical difficulty often resulted in a false-negative diagnosis. It was also difficult to identify the twisted
vascular pedicle by the transabdominal approach,
which was used only in virginal or pregnant women,
and the diagnosis of malignancy preceded the diagnosis of ovarian torsion in patients with malignant
Figure 2 35 year old patient with 720 degree torsion of the left ovary and teratoma. A, TVS shows a 4 cm round mass with heterogeneous echoes (arrows) lateral to the ovarian tumor. B,TV-CDS shows vascular structures with a whorled appearance within the twisted vascular pedicle. C, Color Doppler flow velocimetry demonstrates arterial and venous flow within the vascular
structures, but end diastolic flow of the artery is absent. D, Excised specimen shows the twisted vascular pedicle and ovary as
well as teratoma with hemorrhagic necrosis.
A
B
C
D
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OVARIAN TORSION: TWISTED VASCULAR PEDICLE
ovarian tumor. On the other hand, a false-positive
diagnosis could be made in cases of ovarian
tumor–associated salpingitis, endometriosis, or hemorrhagic cyst–associated edema, since these conditions could have similar findings. In fact, two
false-positive diagnoses were made in patients with
follicular cyst and hemorrhagic corpus luteum cyst
associated with salpingitis or edema; in these cases
dilated and tortuous vessels within vascular pedicle
were misdiagnosed as the twisted vascular pedicle.
TVS and CDS are expected to demonstrate the
ovarian blood supply, and there have been few
reports of an enlarged ovary with absent or
markedly diminished ovarian blood flow as a specific finding for the early diagnosis of ovarian torsion
using CDS.6,7 Other studies demonstrated the presence of normal arterial flow in three confirmed cases
of ovarian torsion, which suggested the venous
thrombosis without arterial occlusion and dual
blood supply of the ovary as a possible explanation
for the symptoms of ovarian torsion.8 These different
results indicated that in partial torsion or earlier
stages of torsion, before arterial occlusion, both arterial and venous flow could be maintained with
viable ovarian tissue.
The most common method for treatment for ovarian 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 papers have
reported the practice of untwisting of the vascular
pedicle not only to conserve ovarian function but
J Ultrasound Med 17:83–89, 1998
also to preserve fertility without thromboembolism
after detorsion.10–12 In an attempt to ascertain the viability of the ovarian tissue for conservative management of the twisted adnexa, gross inspection or the
application of intravenous fluorescent dye at surgery
has been used, but this technique proved to be difficult to perform preoperatively.13 However, sonography with color Doppler imaging may be used to
predict the ovarian tissue viability by demonstrating
ovarian blood flow. Recent reports have suggested
that documentation of intraovarian venous flow was
important in establishing the viability of the affected
ovaries.9 Other experimental data have shown that
the arterial waveforms in chronic torsion mimic
venous ones.14 In this study, we performed CDS in
the twisted vascular pedicle, instead of the ovarian
parenchyma, to assess the viability ovary in cases of
torsion. All patients who showed no blood flow
within the twisted vascular pedicle on CDS demonstrated hemorrhagic infarction and necrosis of the
adnexal structures. Of 16 patients with arterial and
venous flow within the twisted vascular pedicle on
CDS, 15 patients had nonnecrotic ovaries on pathologic examination or viable ovaries on follow-up
sonography after untwisting of the vascular pedicle,
showing 94% predictability of the viability of the
adnexal structure. Therefore, the presence of arterial
and venous intrapedicular flow was correlated with
nonnecrotic adnexa on pathologic examination and
might aid in differentiating potentially viable ovaries
from nonviable ovaries. However, the waveform of
arterial flow showed absent end diastolic flow in one
patient with pathologically confirmed hemorrhagic
Figure 3 56 year old patient with 720 degree torsion of the right ovary and teratoma. A, TVS shows a 6 × 4 cm round mass with
heterogeneous echoes (arrows) adjacent to the ovarian tumor. B, TV-CDS demonstrates no blood flow within the twisted vascular pedicle. Pathologic examination revealed hemorrhagic necrosis of the ovary and tube.
A
B
J Ultrasound Med 17:83–89, 1998
infarction. Therefore, if arterial and venous flow
were maintained in the intrapedicular vessels,
decreased or absent arterial end diastolic flow could
be interpreted as a sign of nonviability of the
adnexal structures. In this study, the patients who
had intrapedicular blood flow on CDS were treated
conservatively by untwisting of the vascular pedicle
to preserve the ovary. In these conservatively managed cases, none showed thromboembolism or
retorsion, and subsequent sonography revealed normal ovaries with follicular development and ovulation. These results suggest CDS findings of flow
within the twisted vascular pedicle could indicate
viability of adnexal structures.
Nevertheless, it is still unclear if the sonographic
findings, intraoperative visual impression, and
pathologic findings are sufficient to decide whether
there is a chance of ovarian preservation or not.
Therefore, the correlation of CDS diagnosis of presence or absence of blood flow within the twisted
vascular pedicle and the possibility of ovarian viability after detorsion should be investigated in a
long-term follow-up study.
In conclusion, it is suggested that the identification of the twisted vascular pedicle through ultrasonography is suggestive of ovarian torsion and it
may be useful in preoperative diagnosis of this
pathologic condition. CDS can be helpful in predicting the viability of the twisted adnexal structures by
depicting arterial and venous flow within the
twisted vascular pedicle, and it may allow prediction of which patients may undergo conservative
management of ovarian torsion.
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89
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