Imaging in gynecological disease (20): clinical and ultrasound characteristics of adnexal torsion

Abstract

Objectives To describe the clinical and ultrasound characteristics of adnexal torsion. Methods This was a retrospective study. From the operative records of the eight participating gynecological ultrasound centers, we identified patients with a surgically confirmed diagnosis of adnexal torsion, defined as surgical evidence of ovarian pedicle, paraovarian cyst and/or Fallopian tube twisted on its own axis, who had undergone preoperative ultrasound examination by an experienced examiner, between 2008 and 2018. Only cases with at least two available ultrasound images and/or videoclips (one grayscale and one with Doppler evaluation) were included. Clinical, ultrasound, surgical and histological information was retrieved from each patient's medical record and entered into an Excel file by the principal investigator at each center. In addition, two authors reviewed all available ultrasound images and videoclips of the twisted adnexa, with regard to the presence of four predefined ultrasound features reported to be characteristic of adnexal torsion: (1) ovarian stromal edema with or without peripherally displaced antral follicles, (2) the follicular ring sign, (3) the whirlpool sign and (4) absence of vascularization in the twisted organ. Results A total of 315 cases of adnexal torsion were identified. The median age of the patients was 30 (range, 1–88) years. Most patients were premenopausal (284/314; 90.4%) and presented with acute or subacute pelvic pain (305/315; 96.8%). The surgical approach was laparoscopic in 239/312 (76.6%) patients and conservative surgery (untwisting with or without excision of a lesion) was performed in 149/315 (47.3%) cases. According to the original ultrasound reports, the median largest diameter of the twisted organ was 83 (range, 30–349) mm. Free fluid in the pouch of Douglas was detected in 196/275 (71.3%) patients. Ovarian stromal edema with or without peripherally displaced antral follicles was reported in the original ultrasound report in 167/241 (69.3%) patients, the whirlpool sign in 178/226 (78.8%) patients, absent color Doppler signals in the twisted organ in 119/269 (44.2%) patients and the follicular ring sign in 51/134 (38.1%) patients. On retrospective review of images and videoclips, ovarian stromal edema with or without peripherally displaced antral follicles (201/254; 79.1%) and the whirlpool sign (139/153; 90.8%) were the most commonly detected features of adnexal torsion. Conclusion Most patients with surgically confirmed adnexal torsion are of reproductive age and present with acute or subacute pain. Common ultrasound signs are an enlarged adnexa, the whirlpool sign, ovarian stromal edema with or without peripherally displaced antral follicles and free fluid in the pelvis. The follicular ring sign and absence of Doppler signals in the twisted organ are slightly less common signs. Recognizing ultrasound signs of adnexal torsion is important so that the correct treatment, i.e. surgery without delay, can be offered. Copyright © 2020 ISUOG. Published by John Wiley &...

Predictive Value of Single or Combined Ultrasound Signs in the Diagnosis of Ovarian Torsion

“…Lee et al 13 demonstrated that in 16 of 28 patients with a diagnosis of torsion at surgery, both arterial flow and venous flow were identified in the pedicle on color Doppler evaluations and were highly correlated with ovarian viability. Moro et al 11 showed a higher prevalence of identification of the whirlpool sign (90.8%). We speculate that the higher prevalence of identification of the whirlpool sign in the study by Moro et al 11 may have been related to the exclusion of 162 of 315 (51%) of cases because of inadequate images and a method wherein only surgically proven cases of adnexal torsion were included.…”

“…Moro et al 11 showed a higher prevalence of identification of the whirlpool sign (90.8%). We speculate that the higher prevalence of identification of the whirlpool sign in the study by Moro et al 11 may have been related to the exclusion of 162 of 315 (51%) of cases because of inadequate images and a method wherein only surgically proven cases of adnexal torsion were included. In our study, this finding was retrospectively identified in an additional 18 patients during the cine loop review, which suggests that actively searching for this sign may improve its detection.…”

“…To our knowledge, only 1 previous study 10 assessed predictive values of ultrasound signs in combination for the diagnosis of ovarian torsion. The largest published study on adnexal torsion ultrasound signs by Moro et al 11 looked at 4 predefined ultrasound signs and found that ovarian stromal edema with or without peripherally displaced antral follicles (201 of 254 [79.1%]) and the whirlpool sign (139 of 153 [90.8%]) were the most commonly detected features of adnexal torsion. A key limitation of their study was permitting inclusion of studies with as few as 2 images, thus resulting in subsequent exclusion on the basis of suboptimal imaging in as many as 49% of cases for an individual sign.…”

Adnexal Torsion: Review of Radiologic Appearances

“…Intervening regions of increased echogenicity may indicate hemorrhagic infarction (49). The follicle-containing cortex becomes stretched around the periphery of the medulla, creating a thin layer of follicles that resembles a string of pearls, which is visible as multiple hypoechoic avascular cystic structures (Fig 9) (39). An additional sonographic finding is that of a hyperechoic rim surrounding peripherally displaced antral follicles, known as the "follicular ring" sign, with the rim measuring 1-2 mm in thickness (50).…”

“…US facilitates dynamic assessment in multiple planes to identify this finding as the characteristic "whirlpool" (twisting of the hypoechoic vessels with or without a color Doppler signal) or "target" (concentric alternating hypo-and hyperechoic rings) sign if it is visualized perpendicular to the rotational axis (Figs 2, 10). Although this sign is present in more than 90% of confirmed cases of adnexal torsion (39), it can be subtle, depending on the number of twists and structures involved (51).…”