Meta-analysis and systematic review to determine the optimal imaging modality for the detection of bladder deep endometriosis

Objective: To review the diagnostic accuracy and determine the optimum imaging modality for the detection of bladder deep endometriosis (DE) in women with a clinical suspicion of endometriosis. Methods: A systematic review of studies published from inception to May 2020 using Embase, Google Scholar, Medline, PubMed and Scopus. Prospective studies, which pre-operatively assessed any imaging modality for the presence of bladder DE, and correlated with the gold standard surgical data as a reference were included. The QUADAS-2 tool was used to assess quality. This review was prospectively registered with PROSPERO (CRD42017059872). Results: Of the 1,977 references identified, 8 studies (n = 1,052) were included in the analysis. The overall pooled sensitivity and specificity, from which the likelihood ratio of a positive test (LR+), likelihood ratio of a negative test (LR-) and diagnostic odds ratio (DOR) were calculated, for all transvaginal ultrasonography (TVS) techniques were 55 % (95 % CI 28–79%), 99 % (95 % CI 98–100%), 54.5 (95 % CI 18.9–157.4), 0.46 (95 % CI 0.25 – 0.85) and 119 (95 % CI 24–577), and for only two-dimensional (2D) TVS 53 % (95 % CI 23–82%), 99 % (96 % CI 97–100%), 48.8 (95 % CI 13.1–181.4), 0.47 (95 % CI 0.23 – 0.98), and 104 (95 % CI 15–711), respectively. Meta-analyses of the other modalities, namely magnetic resonance imaging (MRI) and transrectal endoscopic sonography (RES), were not possible due to the limited number of studies. There was significant heterogeneity and the studies were considered poor methodologically according to the QUADAS-2 tool. Conclusions: Whilst the sensitivity of TVS was limited, the specificity was excellent. Given that there is a paucity of literature for other imaging modalities, until more studies are performed, TVS should be considered as the first-line tool given it is the only modality with sufficient evidence.