A meta-analysis of b-mode ultrasound, Doppler ultrasound, and computed tomography to diagnose pediatric ovarian torsion

Purpose Ovarian torsion (OT) is a true surgical emergency that requires prompt diagnosis and therapy. There are conflicting reports on the accuracy of different imaging modalities for OT. In this study, we performed a meta-analysis of all the published studies on B-mode ultrasound (US, morphological criteria), Doppler US (DUS, flow criteria), and computed tomography (CT) for the diagnosis of OT. Methods The medical literature from 1987 to 2013 was searched for studies that evaluated US, DUS, CT, or combination of these techniques to diagnose OT in children using PubMed/MEDLINE database. The studies were screened and included if the quality criteria were met. Data were extracted using a standardized form. Reported sensitivities and specificities were pooled with 95% confidence intervals using a RevMan version 5.1 software (The Cochrane Collaboration, Oxford, United Kingdom). Results A total of 18 US studies with 716 combined patients were included, along with 15 DUS studies comprising of 1,021 patients, and 5 CT studies with a total of 107 patients. All studies reported sensitivities, while only few selected studies also reported specificities. Using morphological criteria on B-mode US (including absolute or relative ovarian size, echotexture, location, and configuration) yielded high sensitivity and specificity (average 92 and 96%, respectively); DUS was highly specific, but lacked sensitivity, while CT was the least sensitive test. CT specificities could not be calculated from the available data. Conclusion This study found considerable variability of the reported sensitivities and specificities for the diagnosis of OT across all evaluated imaging modalities. Interestingly, B-mode US was the most sensitive and specific examination to detect OT. Some authors reported high diagnostic accuracy of DUS as well, but these findings have not been universally reproduced. CT had low overall sensitivity and is not recommended for the workup of suspected OT.