Diagnostic Value of MR Imaging in the Diagnosis of Adnexal Torsion

PURPOSE: To retrospectively evaluate the diagnostic performance of magnetic resonance (MR) imaging for the diagnosis of adnexal torsion in a series of patients with an equivocal adnexal mass at ultrasonography (US) in the context of acute or subacute pelvic pain. MATERIALS AND METHODS: The institutional ethics committee approved the study and waived informed consent. All patients with acute or subacute pelvic pain who were undergoing MR examination for the exploration of an equivocal adnexal mass (January 2007 to December 2012) with surgical exploration or clinical and radiologic follow-up of at least 3 months were retrospectively included (n = 58). The prospective interpretations were recorded. Additionally, three radiologists who were blinded to the clinical, US, and surgical data retrospectively and independently reviewed MR images. Features associated with adnexal torsion were identified by using univariate and recursive partitioning multivariate analysis. RESULTS: Twenty-two patients (38%) had a diagnosis of adnexal torsion. The accuracy of MR imaging at the time of prospective interpretation was 80.6% (25 of 31 patients) and 85.1% (23 of 27 patients) in acute and subacute torsion, respectively. The accuracy of image interpretation by each retrospective reader was 83.9% (26 of 31 patients), 90.3% (28 of 31 patients), and 83.9% (26 of 31 patients) in the context of acute pelvic pain and 92.6% (25 of 27 patients), 88.9% (24 of 27 patients), and 81.5% (22 of 27 patients) in the context of subacute pelvic pain for readers 1, 2, and 3, respectively. At multivariate analysis, the whirlpool sign (odds ratio = 6.5 [95% confidence interval: 1.36, 31.0], P = .01) and a thickened tube (>10 mm) (odds ratio = 8.2 [95% confidence interval: 1.2, 56.8], P = .03) were associated with adnexal torsion, with substantial interreader agreement (κ = 0.71-0.84 and 0.82-0.86, respectively). The presence of adnexal hemorrhagic content was associated with nonviable ovaries in seven of 10 patients (70%) and with viable ovaries in 12 of 45 patients (27%) (P = .009). CONCLUSION: MR imaging is an accurate technique for the diagnosis of adnexal torsion in patients who have an adnexal mass with acute or subacute pelvic pain.