Ultrasound scan and magnetic resonance imaging for the diagnosis of adenomyosis: systematic review comparing test accuracy

Background. Adenomyosis is a common condition that causes substantial morbidity. Until recently, the reference standard for a definitive diagnosis was histology of hysterectomy specimens. Ultrasound and magnetic resonance imaging (MRI) may allow accurate non-invasive diagnosis. Objective. To compare the diagnostic accuracy of these techniques. Design. Systematic review with meta-analysis. Population. Women who had ultrasound and/or MRI, and whose results were compared with a reference standard. Methods. Electronic searches were conducted in literature databases from database inception to 2010. The reference lists of known relevant articles were searched for further articles. Selected studies reported data on ultrasound and/or MRI with histological confirmation of diagnosis. Two reviewers independently selected articles without language restrictions, and extracted data in the form of 2 x 2 tables. We computed sensitivity and specificity for individual studies and pooled these results in a meta-analysis. We also performed meta-regression to examine how the index tests compared on diagnostic accuracy. Results. Twenty-three articles (involving 2,312 women) satisfied the inclusion criteria. Transvaginal ultrasound had a pooled sensitivity of 72% (95% CI 65-79%), specificity of 81% (95% CI 77-85%), positive likelihood ratio of 3.7 (95% CI 2.1-6.4) and negative likelihood ratio of 0.3 (95% CI 0.1-0.5). MRI had a pooled sensitivity of 77% (95% CI 67-85%), specificity of 89% (95% CI 84-92%), positive likelihood ratio of 6.5 (95% CI 4.5-9.3), and negative likelihood ratio of 0.2 (95% CI 0.1-0.4). The results show that a correct diagnosis was obtained more often with MRI. Conclusion. Transvaginal ultrasound and MRI show high levels of accuracy for the non-invasive diagnosis of adenomyosis.