US findings of adnexal torsion in children and adolescents: size really does matter.

Background: Adnexal torsion is rare, and symptoms are nonspecific. Clinicians often rely on US examinations to evaluate girls with abdominal or pelvic pain.

Objective: To determine which sonographic findings can predict adnexal torsion by comparing pediatric and adolescent patients with surgically confirmed torsion (cases) to those without torsion (controls).

Materials And Methods: Cases and controls were identified retrospectively by searching 7 years of medical record and radiology databases. An adnexal ratio was calculated as the volume of the affected adnexa divided by the volume of the unaffected adnexa.

Results: We identified 61 menarchal subjects: 33 cases and 28 controls. Adnexal volume was larger in cases than in controls (185 vs. 37.8 ml, P < 0.001). A volume of >75 ml was more common in cases than in controls (64 vs. 15%, P < 0.001). No cases had an adnexal volume of <20 ml (P < 0.001). The adnexal ratio was larger in cases than in controls (16.1 vs. 6.7, P < 0.001). An adnexal ratio of >15 was seen in 40% of cases and in no controls (P = 0.08). Doppler US results were not predictive of torsion.

Conclusion: An adnexal volume of <20 ml is strong evidence against adnexal torsion in menarchal females. In this age group, the diagnosis of torsion cannot be established by US examination alone.