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Original Research |
1 Department of Radiology, University of Michigan Health System, UH B2 A-209-R,
1500 E Medical Center Dr., Ann Arbor, MI 48109-0030.
2 Department of Biostatistics, School of Public Health, University of Michigan
Health System, Ann Arbor, MI.
Received May 27, 2005;
accepted after revision November 12, 2005.
Presented at the 2005 annual meeting of the American Roentgen Ray Society,
New Orleans, LA.
Abstract
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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MATERIALS AND METHODS. Two blinded radiologists retrospectively reviewed the MRI examinations of 87 patients with 95 sonographically indeterminate adnexal masses. Reviewers determined the origin of a mass, its tissue content (cystic, solid, complex cystic, or cystic and solid), tissue characteristics (fat, blood, fibrous, or leiomyomatous), and benignity versus malignancy. Sonograms were reviewed by three reviewers to determine the origin of a mass, its tissue content, and reasons for an indeterminate diagnosis. Sensitivity and specificity of MRI were calculated, and agreement of sonography and MRI with the final diagnosis was determined using kappa statistics. The final diagnosis was determined by histopathology, surgical findings, or imaging or clinical follow-up.
RESULTS. The sensitivity of MRI for identifying malignancy
(n = 5) was 100% and its specificity for benignity (n = 90)
was 94%. Excellent agreement was seen between MRI and the final diagnosis for
determining the origin (
= 0.93), tissue content ( = 0.98), and
tissue characteristics ( = 0.91) of a mass. Sonography had poor
agreement with the final diagnosis for the origin ( = 0.19) and tissue
content ( = 0.33) of a mass. The main reasons for indeterminate
sonographic diagnoses were the inability to determine origin because of
location and large mass size and the appearances of purely solid or complex
cystic masses.
CONCLUSION. Sonographically indeterminate adnexal masses of uncertain origin and solid or complex cystic content benefit from further evaluation with MRI, which is highly accurate for identifying the origin of a mass and characterizing its tissue content, obviating surgery.
Keywords: adnexal masses • MRI • obstetric and gynecologic imaging • pelvic imaging • reproductive organ imaging • sonography
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Sonography is the initial imaging study of choice in the evaluation of women with suspected adnexal masses because of its widespread availability, relatively low cost, and high sensitivity in the detection of masses [1, 2]. However, sonography is limited by its decreased specificity for the diagnosis of benignity, which can vary from 60% to 95% and result in as many as 20% of adnexal masses being classified as indeterminate [3, 4].
The ability of MRI to accurately characterize clinically or sonographically indeterminate adnexal masses has been previously documented in the literature [3, 5-9]. Early studies focused on the usefulness of MRI in diagnosing benign entities (leiomyomas, dermoids, endometriomas) [5, 6], whereas the recent literature has reported multiple MRI features specific for ovarian malignancy [3, 7, 8]. None of these investigations have addressed the reasons that rendered the masses indeterminate on sonography. The knowledge that certain sonographic features of adnexal masses may frequently result in an incorrect diagnosis of ovarian malignancy or an indeterminate mass may be important in determining whether the next step should be surgical exploration or pelvic MRI, which might offer a more accurate characterization of the mass, potentially leading to a benign diagnosis. Therefore, the purpose of our study was twofold: to assess the ability of MRI to characterize sonographically indeterminate adnexal masses in a generalized female patient population, and to define the sonographic features contributing to misleading or indeterminate diagnoses.
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The final diagnosis for each of the 95 masses was established by the following methods: histopathology (n = 43), surgical findings (n = 6), imaging follow-up (n = 26), and clinical follow-up (n = 20). The average length of imaging follow-up was 18.2 months (range, 1.1-58 months) and of clinical follow-up was 27.7 months (range, 1-67 months). The 20 lesions with clinical follow-up were distributed as follows: seven pedunculated fibroids with follow-up of 1, 3, 19.7, 46.3, and 67 months; three classic-appearing endometriomas with follow-up of 4, 20.5, and 45.7 months; one ovarian cancer (patient died and had a cystic and solid mass with mural nodules and a CA-125 level of 3,540); two follicular cysts with follow-up of 33.7 and 43.4 months; three cases in which bowel loops accounted for the "mass," with follow-up of 22.5, 33.7, and 64.9 months; three negative MRI examinations and no explanation of the sonographic findings with follow-up of 33.3, 48.1, and 53.9 months; and one paraovarian (fallopian tube) remnant in a 16-year-old girl with a follow-up of 11 months. Two patients with a total of four masses had classic-appearing pedunculated fibroids and were included in the final study population, despite relatively short periods of clinical follow-up of 1 and 3 months. Similarly, the patient with a classic-appearing endometrioma on MRI and a known history of surgically proven endometriosis was also included despite a follow-up period of only 4 months.
Imaging Techniques
Sonography—Transabdominal and transvaginal sonography
examinations were performed by experienced sonographers using commercially
available scanners (Logiq 700 and Logiq 9, GE Healthcare; ATL-HDI 3500 and
ATL-HDI 5000, Philips Medical Systems; Elegra, Siemens Medical Solutions; and,
Sequoia, Acuson) with standard transducers (3.5-7-MHz transabdominal and
4-8-MHz transvaginal curvilinear array transducer probes). Of 87 patients, 75
underwent both transabdominal and transvaginal sonography, 10 underwent
transabdominal sonography only with no transvaginal scanning (could not
tolerate probe [n = 8], refusal of probe insertion [n = 1],
cervical mass precluding adequate positioning of probe [n = 1]), one
patient underwent only transvaginal scanning because of an empty bladder, and
in one patient the technique could not be ascertained because the sonograms
were not available for review.
MRI—All 87 MRI studies were performed on a 1.5-T scanner (Signa Horizon, GE Healthcare) using a torso phased-array coil. Most women received 1 mg of intramuscular glucagon immediately before scanning began to reduce peristaltic bowel motion artifacts. The following sequences were performed: coronal T2-weighted half-Fourier single-shot fast spin echo (TR/TE range, infinite/50-180; number of excitations, 0.5; range of slice thickness and intersection gap, 5-8 and 0-2 mm; matrix, 256 x 128-160 [frequency x phase]); axial T1-weighted spin echo with an anterior saturation band (TR range/TE range, 400-800/8-14; number of excitations, 2; range of slice thickness and intersection gap, 5-8 and 0-2 mm; matrix, 256 x 192-224 [frequency x phase]); sagittal T2-weighted fast spin echo with an anterior saturation band (3,000-6,000/77-105; number of excitations, 3-4; range of slice thickness and intersection gap, 5-8 and 0-1 mm; matrix, 512 x 224 [frequency x phase]); axial T2-weighted fast spin echo (TR range/effective TE range, 3,000-7,060/79-105; number of excitations, 2-4; slice thickness and intersection gap, 5-8 and 0-2 mm; matrix, 256 x 192-224 [frequency x phase]; and chemically selective fat suppression). Sixty-eight patients also underwent additional T2-weighted fast spin-echo imaging through the long and short axes of the uterus with parameters similar to those of the T2-weighted sagittal fast spin-echo sequence. Unenhanced and enhanced T1-weighted fat-suppressed 2D spoiled gradient-echo (SPGR) imaging was performed in the axial plane (TR range/TE range, 145-300/1.3-3.1; flip angle, 70°; number of excitations, 1; slice thickness and intersection gap, 5-8 and 0-1 mm; matrix, 256-512 x 160 [frequency x phase]; chemically selective fat suppression). Contrast-enhanced images were obtained immediately after the IV hand injection of gadolinium (Magnevist [gadopentetate dimeglumine], Berlex; or Omniscan [gadodiamide], Amersham Health) at a dose of 0.1 mmol/kg of body weight (maximum, 20 mL). Additional coronal and sagittal contrast-enhanced 2D spoiled gradient-echo T1-weighted sequences were performed in some patients to better delineate a lesion (parameters were similar to those used for axial sequences). Eleven patients did not receive IV contrast material.
Image Analysis
Sonography—Three radiologists with 7, 8, and 2 years of
experience in the interpretation of pelvic sonography retrospectively reviewed
the sonograms (hard-copy or digital images) in conjunction with the original
prospective interpretations to determine by consensus the following features
of a mass: origin (ovarian, uterine, or extraovarian); tissue content (solid,
purely cystic, complex cystic, or cystic and solid); and imaging features that
led to an indeterminate sonographic diagnosis. The reviewers were aware of the
history of an indeterminate adnexal mass but were not given the medical
history, MRI findings, or final diagnosis. The rationale for including
original reports as part of the review was to reproduce the circumstances of
the initial prospective interpretation in which the supervising physician
would have had the most information available to best characterize the mass
(e.g., cine imaging and ability to scan the patient after the images are
interpreted).
The following categories were used to describe why a mass was considered sonographically indeterminate: suboptimal image quality (excessive bowel gas, large body habitus, no transvaginal images, poor pelvic detail, shadowing from fibroids), large mass (difficult to determine its origin), location of mass (adjacent to uterus, making it difficult to determine the origin and distinguish between a pedunculated fibroid and an ovarian neoplasm), purely solid mass, purely cystic mass (lack of tissue specificity), and complex cystic appearance of mass with internal echoes (lack of tissue specificity). "Lack of tissue specificity" for solid, cystic, or complex cystic masses implies that the finding is not specific for any one diagnosis and can be seen in a wide spectrum of lesions, including both benign and malignant entities.
MRI—Two body MRI-trained radiologists with 5 and 7 years of experience in pelvic MRI reviewed the images in consensus on a workstation (Advantage Windows, GE Healthcare). The reviewers were aware of the history of a sonographically indeterminate adnexal mass but were blinded to the medical history, sonography findings, and final diagnosis. The following factors were assessed in each patient: presence or absence of a mass, number of masses, origin of mass (ovarian, uterine, or extraovarian), lesion size, and tissue content (solid, purely cystic, complex cystic [indicating the presence of blood], or cystic and solid). If no mass was identified, the MR images were evaluated for findings that could explain the sonographic diagnosis of an indeterminate mass.
For determining tissue content and tissue characterization, the signal characteristics of the mass on T1- and T2-weighted images were documented as being hypointense, hyperintense, or isointense to skeletal muscle; and the presence of fat, hemorrhage, and fibrous or leiomyomatous tissue was recorded. Fat was identified if a mass showed high signal intensity on T1-weighted images and lost signal intensity on fat-suppressed T1-weighted sequences. Hemorrhage was identified if a mass showed high signal intensity on both non-fat-suppressed and fat-suppressed T1-weighted images. Fibrous and leiomyomatous tissue was defined as being hypointense to skeletal muscle on T2-weighted images as previously documented [10-13]. A thick enhancing wall, internal enhancement, septations, and mural nodules within the mass were used to help characterize a mass as benign or malignant. The presence of an abnormal amount of pelvic fluid, lymph node enlargement, and peritoneal metastases was documented. The reviewers recorded their impressions of whether a lesion was malignant or benign on a scale of 1-4 (1 = benign, 2 = probably benign, 3 = probably malignant, 4 = malignant) and their most likely diagnosis.
Statistical Analysis
The sensitivity and specificity of a correct MRI diagnosis of a mass
(malignant or benign), as determined by the final diagnosis, were calculated
using a two-by-two table and 95% CIs based on the score statistic
[14]. For this purpose, the
MRI categories of "benign" and "probably benign" were
grouped together, as were the categories "malignant" and
"probably malignant."
The sonography and MRI determinations of the origin of each of the 95
masses and their tissue content were compared with the final diagnosis, and
agreement between each imaging method and the final diagnosis was established
using the kappa statistic and 95% CIs based on an estimate of its asymptotic
variance [14] ( = 1.0,
perfect agreement; k 3 0.8 but < 1.0, excellent agreement; k
3 0.6 but < 0.8; good agreement; k 3 0.4 but <
0.6, fair agreement; > 0 but < 0.4, poor agreement; and
= 0, agreement by chance alone). Similarly, the MRI characterizations of
hemorrhage, fat, and fibrous and leiomyomatous tissue were compared with the
final diagnosis using the kappa statistic.
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Origin of Masses
In determining the origin of 20 uterine masses, 50 ovarian masses, 12
extraovarian (extrauterine) lesions, and no mass in 13 patients, sonography
had poor agreement with the final diagnosis, whereas MRI had excellent
agreement (Tables 2 and
3). Sonography was
indeterminate in every case of a uterine mass (17 fibroids and three
müllerian anomalies) because of difficulty in determining its origin
(Figs. 1A,
1B, and
1C) and whether it represented
a pedunculated fibroid or a solid ovarian neoplasm. Thirteen sonographically
questioned masses resulted in negative MRI findings: four of these
"masses" were prominent loops of feces-filled colon that mimicked
a solid mass on sonography, and four cystic masses on sonography were no
longer present on MRI, suggesting that they were probably resolved functional
ovarian cysts. In one patient, a cervical remnant after supracervical
hysterectomy was diagnosed as a possible ovarian mass; and the remaining four
negative MRI examinations had no findings to explain the sonographic
diagnosis. These latter four women were followed up clinically for 2.75, 3.4,
4, and 4.5 years without evidence of a gynecologic malignancy. One of the
patients also had follow-up CT 5 months later that was negative for an adnexal
mass. We believe that these patients had a reasonable period of follow-up
because an ovarian malignancy would have been evident during those follow-up
times.
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The single indeterminate MRI diagnosis of an ovarian mass was a large (11-cm) ovarian fibroma in a postmenopausal woman that was difficult to differentiate from a large pedunculated fibroid because neither ovary was identified. Of three extraovarian masses misdiagnosed as ovarian in origin on MRI, two (peritoneal inclusion and paratubal cysts) were thought to represent ovarian cystadenomas; and one broad-ligament fibroid was misdiagnosed as ovarian carcinoma. In each of these cases, nonvisualization of separate ovaries in postmenopausal women contributed to the diagnostic dilemma.
Tissue Content and Characterization of Masses
In determining the tissue content of 26 cystic masses, 33 solid masses,
three cystic and solid masses, 17 complex cystic masses, and no true adnexal
mass in 16 patients (no mass [n =12], cervical remnant [n =
1], müllerian anomaly [n = 3]), sonography had poor agreement
with the final diagnosis and MRI had excellent agreement
(Table 2).
No specific findings on MRI or histopathology explain why 11 purely cystic masses were found to have internal echoes and solid debris on sonography and were therefore misclassified as complex cystic (n = 9) or cystic and solid (n = 2) masses. Of four incorrectly characterized solid masses, two dermoids and one pedunculated uterine fibroid were thought to represent complex cystic ovarian neoplasms, and one dermoid was suspected of being a cystic and solid ovarian malignancy. On gross sectioning, cystic elements and gelatinous or keratin material were identified in two of the dermoids, which could explain the sonographic appearance. Similarly, scattered areas of hemorrhage were found in the fibroid, which probably accounts for its complex appearance on sonography. Although 11 endometriomas and hemorrhagic cysts were correctly classified as complex cystic masses with internal echoes on sonography, no definitive diagnosis of a benign hemorrhagic mass was made on sonography; rather, the possibility of an ovarian cystic neoplasm was entertained in each case. Sonography incorrectly categorized five benign endometriomas as possible solid ovarian neoplasms (Figs. 2A, 2B, and 2C) and one endometrioma as a cystic and solid ovarian neoplasm. In one of three histopathology-proven "solid" endometriomas, the presence of a fibrotic wall and stromal hyperplasia probably accounted for the solid appearance of the mass on sonography.
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= 0.91, 95% CI = 0.83-0.99) with
the final diagnosis for identifying specific tissue characteristics (fat,
hemorrhage, fibrous and leiomyomatous tissue). This enabled the accurate
diagnosis of dermoids, hemorrhagic cysts, endometriomas, uterine fibroids, and
fibrous tumors of the ovary (Figs.
3A,
3B,
3C, and
3D).
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Sonographic Features of an Indeterminate Diagnosis
In evaluating the sonographic features leading to an indeterminate
diagnosis, we found that many of the lesions belonged in two or more of the
six assigned categories. Only 11 cases were indeterminate solely because of
suboptimal technique. The three most common sonographic reasons for an
indeterminate mass were location of the mass (n = 40), solid
appearance (n = 33), and complex cystic appearance (n = 34).
Sonography had difficulty in establishing whether a mass located adjacent to
the uterus was a pedunculated fibroid or an ovarian mass (Figs.
5A and
5B). In 29 cases in which the
prospective sonographic interpretation stated "an adnexal mass could
represent an ovarian mass or pedunculated fibroid," the following
distribution of masses was noted: uterine fibroids (n = 14); no mass
(n = 2); broad-ligament fibroid (n = 2); müllerian
anomaly (n =1); and ovarian mass (n = 10), including two
ovarian cancers, four ovarian fibromas, two dermoids, and two endometriomas.
Less common reasons for an indeterminate diagnosis included cystic appearance
of an ovarian mass (n =16), which is a nonspecific finding that can
be seen in ovarian epithelial neoplasm and simple serous cysts; and large mass
size (n = 5), which resulted in difficulty in determining the origin
as being uterine or ovarian.
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These issues justify the need to recognize which sonographic features routinely result in an indeterminate or suspicious diagnosis and to determine whether MRI is the appropriate next step. Surprisingly, only 11 indeterminate diagnoses were the result of technically limited sonograms; rather, a specific imaging feature of a mass more commonly yielded an indeterminate diagnosis.
Our study reveals that sonography performs poorly for determining the origin of the mass, which is the essential first step in characterizing an adnexal mass. For example, although a solid intrauterine mass is likely a fibroid, a solid mass located adjacent to the uterus may be a pedunculated uterine fibroid or an ovarian mass. In our study, 48% of such masses were pedunculated fibroids and 34% were ovarian masses. Large mass size was an additional contributing factor to an indeterminate sonographic diagnosis in five cases. Unless specific features of fibroids can be identified, such as refractory shadowing, these large solid pelvic masses remain diagnostic dilemmas on sonography [16, 17]. Unlike sonography, excellent agreement was seen between MRI and the final proven origin of a mass. This stresses the importance of MRI as the best next step in evaluating such a mass before subjecting a patient to surgery that might be unnecessary. Our results in accurately characterizing an adnexal mass as a pedunculated uterine fibroid (17/18 masses) are similar to those reported in prior MR studies [5, 6].
Because fibrous tumors of the ovary have imaging features similar to those of fibroids, such as low signal intensity on T2-weighted images, the recognition of the stalk of the fibroid and the identification of separate normal ovaries can help confirm the diagnosis of a fibroid. In postmenopausal women, identification of atrophic ovaries can be problematic and the uterus may be small, which limits visualization of a stalk [6, 18]. In such cases, the identification of vessels bridging the mass and the uterus on T2-weighted and gadolinium-enhanced images ("bridging vascular" sign) has an accuracy of 80% for the diagnosis of pedunculated uterine fibroids [18].
Our study also documented that eight indeterminate "masses" on sonography were not masses but a cervical remnant, müllerian anomaly, or low-lying bowel filled with feces. MRI is well suited to the characterization of uterine and cervical tissue and the evaluation of congenital uterine anomalies [19, 20]. MRI can also be used to reliably characterize bowel loops in the pelvis by identifying bowel contents of high T1 and low T2 signal intensity, which is caused by the presence of paramagnetic substances such as manganese that are found in commonly ingested foods (i.e., chocolate, fruits). These substances result in high-signal-intensity bowel contents on T1-weighted imaging [21].
Extraovarian cystic masses can pose a diagnostic challenge on sonography and MRI. The advantage of MRI is its ability to reveal separate normal ovaries and to delineate the characteristic morphologic features of a mass on multiple imaging planes, such as the pathognomonic tortuous folded appearance of a hydrosalpinx [11]. Likewise, peritoneal inclusion cysts, which are fluid trapped in the peritoneal cavity, have a characteristic appearance in that the fluid is unusually shaped and conforms to the peritoneal spaces rather than having the round or ovoid appearance of a cystic ovarian neoplasm [22].
Our study showed that accurate tissue characterization, the second essential component of characterizing an adnexal mass, was poor for sonography and excellent for MRI. The entire spectrum of benign and malignant pelvic masses appeared solid on sonography in our study, and benign masses sometimes appeared complex on sonography, thereby mimicking a malignancy. Unenhanced T1- and T2-weighted imaging is important for accurate tissue characterization. Lipid and blood are readily detected on T1-weighted imaging with and without fat suppression [11, 13, 23, 24]. T2-weighted imaging helps to identify the relatively low signal intensity of endometriomas, reflecting blood degradation products from repeated cyclical bleeding [11] or the very low signal intensity of fibrous tissue in a fibrous tumor of the ovary (i.e., Brenner tumor, ovarian fibroma, fibrothecoma) [10, 12, 13]. Gadolinium is usually reserved for improved delineation of papillary projections, nodules, and thick enhancing septations in ovarian cancers [3, 25, 26].
Although we correctly classified eight purely cystic unilocular ovarian masses as benign or probably benign, we could not distinguish between a functional ovarian cyst and a serous cystadenoma to prevent surgery in seven patients. Although MRI is sensitive for the detection of the fluid content of a mass [5, 11, 27], it may not add information beyond what is gleaned from a good-quality sonogram for a unilocular, purely cystic ovarian mass. Moreover, the size of a simple unilocular cyst has little correlation with the likelihood of malignancy [11]. Therefore, the more appropriate and cost-effective way of managing such a mass in a premenopausal woman is to perform follow-up sonography for interval resolution.
The high specificity (94%) for establishing a benign diagnosis in our study is similar to that reported by Scoutt et al. [5] (fibroids, 100%; dermoids, 99%; endometriomas, 91%). Our specificity is slightly higher than reported by Hricak et al. [3], which may be explained by their larger number of cystic ovarian masses (53/91 lesions), which are difficult to characterize as benign because of lack of tissue specificity. We also had müllerian anomalies and a larger number of uterine fibroids (17 vs 3), which are more readily diagnosed as benign, than did Hricak et al. The radiologist's subjective impression of malignancy versus benignity was highly accurate in our study, which supports prior conclusions that subjective assessment is one of the best discriminators in making such a diagnosis [7]. The false diagnoses of ovarian cancer occurred with cystic ovarian masses because of large mass size (> 4 cm) and lack of tissue specificity and with a solid adnexal mass that was a broad-ligament fibroid having intermediate signal intensity on T2-weighted images and avid enhancement, two features suggestive of malignancy. Although our sensitivity for the detection of ovarian malignancy was 100%, our study population comprised five cancers, which makes it difficult to extrapolate the data. Most (95%) of our patients were referred from primary care physicians and gynecologists, and only 5% were referred from gynecologic oncologists; therefore, our overall results could be generalized to a typical community population. Prior MRI studies have reported a greater number of ovarian malignancies, which reflects a patient selection bias because their patients were predominantly referred from gynecologic oncology [3, 7].
Our study has a number of limitations. Because of the small sample size and the overlap of categories of reasons for a mass being indeterminate on sonography, we could not perform a statistical analysis of these data. Moreover, the small number of benign cystic ovarian neoplasms in our study does not allow us to provide a statistical defense of our observation that MRI may not provide additional information in characterizing unilocular cystic ovarian masses. Our study also has a patient selection bias because we did not evaluate patients who were directed to surgery after an indeterminate sonography diagnosis but who did not undergo MRI. Sonograms in our study were interpreted in the absence of prior examinations, and many indeterminate lesions might have been characterized on serial sonography examinations. Our method of reviewing sonograms obtained by a technologist might have resulted in an inherent bias against the ability of sonography to characterize masses. In countries where experienced radiologists typically perform sonography, the discrimination of such masses may be more extensive and accurate. However, the goal of this study was not to compare the accuracy of MRI and sonography; rather, it was to evaluate the ability of MRI to provide additional useful information in cases of indeterminate sonographic findings. In addition, our sonography practice may reflect those radiology practices in which the high volume of cases necessitates that technologists acquire the images. Finally, because this was a retrospective study, we do not have histologic proof of all diagnoses. An argument could be made that kappa statistics should be performed only on histopathologically proven lesions and that clinical follow-up alone is inadequate. However, such an analysis would ignore the many benign lesions that do not require pathologic confirmation for diagnosis because of their pathognomonic appearance. Our study also reflects real-life experience because these patients would not undergo surgical exploration but would be followed up clinically or with imaging, or may not require follow-up in the absence of any disorder.
In conclusion, the strengths of MRI in the evaluation of an adnexal mass are its abilities to accurately determine the origin of a mass and to characterize its content. Our small sample indicates that MRI may not offer any additional information in characterizing a unilocular cystic ovarian lesion. Common sense would dictate that patients with a suspected adnexal mass would benefit from MRI if their sonographic studies are technically limited. However, our study also suggests that if sonography detects an adnexal mass with solid or complex cystic tissue, a large mass, or a questionable pedunculated uterine fibroid versus ovarian neoplasm, the threshold for triaging patients to MRI for further evaluation should be low. The high accuracy of MRI in identifying the origin of an adnexal mass and characterizing its solid, hemorrhagic, fatty, and fibrous content may obviate surgery or significantly contribute to the preoperative planning of a sonographically indeterminate mass.
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