Surgical Science, 2011, 2, 326-330
doi:10.4236/ss.2011.26069 Published Online August 2011 (
Copyright © 2011 SciRes. SS
Validity of Ultrasound in Patients with Acute Pelvic Pain
Related to Suspected Ovarian Torsion
Leena Mawaldi1, Charu Gupta1, Hanadi Bakhsh1, Maissa Saadeh2, Mostafa A. Abolfotouh2*
1Department of Obstetrics and G ynaecology, King AbdulAziz Medical City, National Guard Health Affairs,
Riyadh, Saudi Arabia
2King Abdullah International Medical Research Center (KAIMRC), King Saud Bin-Abdulaziz University fo r
Health Sciences, National Guard Health Affairs, Riyadh, Saudi Arabia
*E-mail: m
Received April 27, 2011; revised July 2, 2011; accepted July 18, 2011
Objective: Ultrasound has been proven to be useful in detecting underlying ovarian pathology. However, its
role in the prediction of ovarian torsion has been controversial. The aim of the study was to assess the valid-
ity of ultrasound in the prediction of ovarian torsion in patients with acute pelvic pain related to clinically
suspected ovarian torsion. Methods: A retrospective observational study was conducted at the Ob/Gyn de-
partment using a 10-year chart review of all female patients older than 11 years of age with highly suspected
ovarian torsion who underwent clinical assessment and ultrasound prior to surgery (n = 62). The sensitivity
and specificity of ultrasound were determined by cross-tabulation of the ultrasound and surgical findings.
Results: Of the suspected cases, 54 (87.1%) were confirmed to be cases of ovarian torsion by surgery. The
majority of the cases were suggestive of ovarian torsion, which was indicated by clinical examination
(77.4%), ultrasound (77.4%), or pathological examination (79%). Almost one-half of the cases (46.8%)
showed a pain score >6; two-thirds (62.9%) presented with vomiting and/or nausea; and more than one-third
(38.7%) presented with leukocytosis. The estimated sensitivity and specificity of ultrasound were 0.74 and
0.0, respectively. The positive predictive value was 0.83. Ultrasound was significantly associated with both
clinical examination (p = 0.039) and pain score (p = 0.008). Conclusion: The diagnosis of ovarian torsion
cannot be exclusively based on ultrasound. Both clinical and sonographical evaluation of acute pelvic pain
should be considered for the diagnosis. A definitive diagnosis remains challenging.
Keywords: Acute Pelvic Pain, Ultrasound, Ovarian Torsion
1. Introduction
Ovarian torsion refers to the twisting of the ovary on its
ligamentous supports, which often results in an imped-
ance of its blood supply. This condition is the fifth most
common gynecological emergency and affects females
of all ages [1]. Expedient diagnosis is important to pre-
serve ovarian function and prevent adverse sequelae [2];
however, the diagnosis can be challenging because the
symptoms are relatively nonspecific. The ovaries were
examined in a large series of patients with surgically
confirmed torsion-associated cysts in 48% and neopla-
sms in 46%; the remainder occurred in normal-appearing
ovaries [3]. Histopathology was benign in over 90% of
patients [3-4]. Whereas anatomic factors usually account
for ovarian torsion in adults, normal ovaries have been
demonstrated in over 50% of ovarian torsion cases in
children under the age of 15 years [5]. In adults, torsion
has also been described following laparoscopic hyster-
ectomy, suggesting that even release of the fulcrum, on
which the ovaries usually twist, does not protect against
torsion [6]. Strenuous exercise or a sudden increase in
abdominal pressure also promotes torsion of the ovary
around the vascular pedicle [7]. The right ovary is more
likely than the left to underg o torsion, suggestin g that the
sigmoid colon may help to prevent torsion [8].
Women who are pregnant [9-10] or are undergoing
ovarian hyperstimulation during infertility treatment are
at increased risk of ovarian torsion [11]. The overall in-
cidence of torsion in pregnant women was reported as
15% [12]. In association with pregnancy, torsion most
commonly occurred between 10 and 17 weeks of gesta-
tion and during the postpartum period. A much lower
incidence was reported in another series of pregnant
women [13-14]. Torsion was half as common as appen-
dicitis during pregnancy [15]. The clinical presentation
of ovarian torsion is nonspecific, and therefore, it is a
challenge for the clinician to recognize this conditio n and
differentiate it from other etiologies.
The two most common presenting features of ovarian
torsion are acute pelvic pain (83%) and an adnexal mass
(72%) [16]. Other symptoms and findings include nausea
and vomiting (70%), stabbing pain (70%), sudden and
sharp pain in the lower abdomen (59%), pain radiating to
the back, flank, or groin (51%), peritoneal signs (3%),
fever (<2%), leukocytosis, and an increased level of In-
terleukin-6 [17,18] .
Ultrasound can detect adnexal lesions and ovarian
enlargement. An enlarged, heterogeneous-appearing ovary
is the most common ultrasound finding [19]; however,
the presence of normal-appearing ovaries does not rule
out the diagnosis [20]. Doppler ultrasound is also con-
troversial [21] because it shows diminishing or absent
ovarian vessel flow in two-dimensional color [21]. The
aim of this study was to assess the valid ity of ultrasound
in the prediction of ovarian torsion in patients with acute
pelvic pain suggestive of ovarian torsion.
2. Methods
A retrospective observational study was conducted in the
Department of Obstetrics and Gynaecology, King Ab-
dulAziz Medical City, Riyadh, Saudi Arabia. All female
patients (n = 62) older than 11 years of age who pre-
sented with acute pelvic pain with highly suspected
ovarian torsion from January 2000 through December
2009 and for whom surgeries were performed within less
than 6 hours of the ultrasound assessment were in cluded.
Patients underwent a transabdominal scan using 3 - 5
MHz probes and a 5 - 7 MHz endovaginal transducer
with both real-time gray-scale and color Doppler imag-
ing. The data were collected by chart review for all pa-
All categorical variables (age, marital status, pregnancy,
pain score, vomiting, white blood cell counts, abdomi-
nal/pelvic exam, ultrasound, and surgery) were recorded,
and their frequency distributi ons were measured.
Sensitivity, specificity, and predictive values were de-
termined by cross-tabulation of the results of ultrasound
and the surgical findings of ovarian torsion as the gold
standard. Based on this tabulation, the sensitivity, speci-
ficity and positive predictive values were computed for
ultrasound. The sensitivity of ultrasound diagnosis com-
pared with the surgical diagnosis “gold standard” was
determined by calculating how frequently the correct
ultrasound diagnosis was made in each surgical diagnosis.
The specificity of the ultrasound diagnosis was deter-
mined by calculating how frequently the ultrasound di-
agnosis was not made when the corresponding surgical
diagnosis was not present. Positive predictability indi-
cated how frequently the ultrasound diagnosis correctly
reflected the surgical diagnosis. In addition, the level of
agreement between the ultrasound diagnosis and the sur-
gical diagnosis was determined by calculating the kappa
The data were analyzed using SPSS version 15.0. All
of the statistical tests were considered significant at a
P-value < 0.05
3. Results
Table 1 shows a summary of the sociodemographic and
clinical characteristics of the 62 cases of suspected ovar-
ian torsion. Of these cases, 54 (87.1%) were confirmed
as cases of ovarian torsion by surgery. The majority of
the cases were suggestive of ovarian torsion, as deter-
mined by clinical examination (77.4%), ultrasound
(77.4%), or pathological examination (79%). Almost
one-half of the cases (46.8%) were associated with a pain
score > 6; two-thirds (62.9%) presented with vomiting
and/or nausea; and more than one-third (38.7%) pre-
sented with leukocytosis.
Table 2 shows that when ultrasound is used for pre-
dicting ovarian torsion, the sensitivity is 74%. That is,
the ultrasound scan correctly diagnosed 74% of ovarian
torsion cases and missed 26% of these cases (false nega-
tives). However, free subjects were misclassified as
ovarian torsion cases (false positives).
Table 3 shows that ultrasound was significantly asso-
ciated with clinical examination (p = 0.039) and pain
score (p = 0.008).
Table 4 shows that positive ultrasound alone is not
predictive of ovarian torsion (PPV = 0.0). Additionally,
examination and pain scores have 100% PPV each, yet
the yield is only 13% and 3.7%, respectively. When re-
lying upon ultrasound and one of these two techniques,
the PPV reaches 87%, and the yield is 74%.
4. Discussion
Ovarian torsion is an uncommon condition; however, it
is the most common gynecological surgical emergency
and has an overall incidence of 2.7% [22]. Awareness of
its clinical and sonographical features may enable
prompt treatment that can spare the ovary. The possible
consequences of delayed diag nosis are serious, including
Copyright © 2011 SciRes. SS
Table 1. Sociodemographic and clinical characteristics of
the 62 cases of suspected ovarian torsion.
Demographics N %
Age Group
11 - 18 years 23 37.1
19 and older 39 62.9
Marital status
Married 31 50.0
Single 31 50.0
Yes 10 16.1
No 52 83.9
Pain Score
Less than 6 33 53.2
More than 6 29 46.8
Vomiting & Nausea
Yes 39 62.9
No 23 37.1
White Blood cells
Increased 24 38.7
Normal 38 61.3
Clinical Examination
Positive 48 77.4
Negative 14 22.6
Yes 49 79.0
No 13 21.0
Positive 48 77.4
Negative 14 22.6
Definitive diagnosis
Positive 54 87.1
Negative 8 12.9
ovarian necrosis, peritonitis, and death. Underlying pa-
thology was found in 79% of the cases. Enlargement of
the ovary was the common predisposing factor, including
polycystic ovary, functional cyst, and ovarian hyper-
stimulation syndrome. There were cases of ovarian tor-
sion without ovarian pathology due to an elongated
Table 2. 2 × 2 table of the ultrasound results and the defini-
tive diagnosis of ovarian torsion.
Ovarian Torsion
Ultrasound Positive Negative Total
Positive 40 8 48
Negative 14 0 14
Total 54 8 62
Sensitivity: 40/54 = 74 %; Specificity: 0/8 = 0.0%; PPV: 40/45 = 83.3%;
NPV: 0/14 = 0 %; Kappa: 0.20, P-value: 0.102.
Table 3. Association of the results of ultrasound and a de-
finitive diagnosis of ovarian torsion with patient character-
Variable Ultrasound Diagnosis
Age 0.61b 0.12b
Marital Status 0.068b 0.71a
Pregnant 0.30b 0.47b
Pain Score 0.008b* 1.00a
Vomiting & nausea 0.90b 0.42b
White blood cells 0.32b 0.47a
Clinical examinat ion 0.039b* 0.86b
Pathology 0.43b 0.22b
*p < 0.05; aFisher’s exact test was applied, bChi-square test was applied.
utero-ovarian ligament in 21% of the cases.
Ultrasound has been proven to be useful in detecting
any underlying ovarian pathology. Lee et al. [21] con-
cluded that identification of the twisted vascular pedicle
through ultrasonogr aphy is suggestive of ovarian tors ion,
and color Doppler sonography could be helpful in pre-
dicting the viability of adnexal structures by depicting
blood flow within the twisted vascular pedicle. Gray-
scale findings typically include asymmetric enlargement,
a solid heterogeneous appearance, and peripheral cystic
areas; however, ultrasound was less capable of deter-
mining ovarian torsion. It shows a sensitivity of 0.74
(resulting in a false reassurance of 26%), and a specific-
ity of 0.0 (resulting in a false warning of 100%), and a
PPV of 0.83 (suggesting it might be useful in the clinical
setting). Pena et al. [23] concluded that abnormal flow
detected by Doppler sonography is highly predictive of
adnexal torsion and is therefore useful in the diagnosis of
ovarian torsion; however, the detection of normal flow
does not necessarily exclude ovarian torsion. Thus, our
results are similar to those of international studies.
The study by Cohen et al. [24] concluded that patients
and surgeons alike should be aware of the difficulty in
Copyright © 2011 SciRes. SS
Copyright © 2011 SciRes. SS
Table 4. Predictive value and yield of different criteria for the diagnosis of ovarian torsion.
Criteria for Diagnosis Positive Negative Total PPV (%) Yield (%)
US only 0 1 1 0.0 0 .0
Exam. only 7 0 7 100.0 13.0
Pain score only 2 0 2 100.0 3.7
US + exam 14 3 17 82.4 25.9
US + pain score 6 1 7 85.7 11.1
US + pain score + exam 20 3 23 87.0 37.0
Pain + exam 1 0 1 100.0 1.9
All negatives 4 0 4 100.0 7.4
Total 54 8 62
*This figure reflects the yield of ultrasound in addition to examination and\or p ain score.
making accurate preoperative diagnoses of acute gyne-
cologic pathologies in the emergency room. In the pre-
sent study, a pain score > 6 (100.0) and an abdominopel-
vic examination (100.0) are highly predictive of the di-
agnosis. However, the yield of cases was very low (13%
for examination and 3.7% for pain score).
Bouguizane et al. [9] concluded th at clinicians must be
aware of possible adnexal torsion in women with acute
pelvic pain; ultrasound is a useful tool in these situations
(10). In the present stud y, the predictive value of US and
pain score is 85.7%, but the number of cases is very low
Ignacioa et al. [25] concluded that an ultrasound im-
age can usually be used to make a diagnosis in conjunc-
tion with clinical parameters; however, this is most dif-
ficult in patients with ovarian torsion. In the present
study, the predictive value of US with only examination
is 82.4%, but again, the yield is low (25.9%). However,
when relying upon US in conjunction with either exami-
nation and/or the pain score, the yield reached 74%.
These were the only two variables that h ad positive asso-
ciations with ultrasound (p = 0.008 for the pain score and
p = 0.039 for the examination). Clinical assessment by
nausea-vomiting, pain score, age group, marital status,
and pregnancy status was not statistically significant in
predicting ovarian torsion, although the PPV was high
for leukocytosis (0.92), existing ovarian pathology (0.89),
and nausea-vomiting (0.87).
5. Conclusions
From the collective findings of this study, and consider-
ing its limitations in terms of sample size, it is concluded
that the definitive diagnosis of ovarian torsion remains
challenging. Both clinical and sonographical evaluation
of acute pelvic pain should be considered for the diagno-
sis of ovarian torsion. The diagnosis cannot be exclu-
sively based on ultrasound only, on the presence or ab-
sence of colo r flow Doppler, or even on the morp hologi-
cal findings. Therefore, surgical intervention is recom-
mended in suspicions of a nonviable ovary in order to
decrease the morbidity.
6. Acknowledgements
The study was approved by the research committee of
King Abdullah International Medical Research Center
(KAIMRC), King Saud Bin-Abdulaziz University for
Health Sciences. Special thanks go to Mr. Mahmoud
Salam, the research coordinator at KAIMRC, for helping
in reference formatting. We also thank the editing service
office of KAIMRC for the English language editing of
the manuscript via a specialist English language copy
editor (American Journal Experts).
7. Conflict of Interest
The authors declare no conflicts of interest.
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