The Sonographic Characteristics of Isolated Fallopian Tube Torsion.

Objective: Isolated fallopian tube torsion (IFTT) presents a challenging preoperative diagnosis. This study investigated the specific sonographic characteristics of IFTT and compared them to the characteristics of ovarian and adnexal torsion.

Design: Retrospective cohort study.

Setting: Tertiary level gynecological ultrasound unit.: 225 women operated for suspected isolated ovarian, fallopian tube or adnexal torsion (ovary and tube) were included.

Interventions: Electronic medical records of patients diagnosed with torsion at our ultrasound unit from 2001 to 2018 were retrieved. Inclusion criteria were women operated for suspicion of isolated ovarian, fallopian tube or adnexal torsion (involving both ovary and tube), with a preoperative sonogram performed in our tertiary level gynecologic ultrasound unit. Patients operated after a sonographic examination in the emergency department were excluded.

Measurements: Patients were divided into 4 groups according to their laparoscopic diagnosis: IFTT, ovarian torsion, adnexal torsion or no torsion. The sonographic characteristics of the groups were compared and the diagnosis was confirmed according to laparoscopy findings.

Main results: IFTT was reported in 28/225 (12.4%) cases. Ovarian volume was significantly lower in IFTT (29.2 ± 44 cm³⁾ compared to ovarian torsion (111 ± 143 cm³, p=.037). There were fewer cases of ovarian edema in IFTT compared to ovarian torsion (12/22 (54.5%) vs. 54/63 (85.7%) respectively, p=.001). IFTT was associated with paraovarian cyst significantly more often than with ovarian torsion (13/24 (54.2%) vs. 4/75 (5.3%), respectively; p=.003). There was no difference between whirlpool sign and location in all forms of torsion. The sensitivity, specificity, Positive predictive value and Negative predictive value for IFTT were 88.4%, 83.3%, 95.8% and 62% respectively.

Conclusion: IFTT has distinct sonographic characteristics, including normal ipsilateral ovary, paraovarian cyst, and whirlpool sign. Awareness of these features may improve the diagnosis of IFTT and promote faster and more efficient treatment. Further studies are needed to establish these characteristics.