Performance of imaging interpretation, intra- and inter-reader agreement for diagnosis of pelvic endometriosis: comparison between an abbreviated and full MRI protocol.

Abstract

To compare the performance of imaging interpretation, intra- and inter-reader agreement between an abbreviated (aMRI) and full (fMRI) MRI protocol for diagnosis of pelvic endometriosis. Seventy consecutive fMRI exams performed under suspicion of pelvic endometriosis were selected. Four radiologists (Rd) (1-10 years experience) independently evaluated presence/absence of endometriosis at 9 anatomic sites (AS). The readers evaluated aMRI (coronal T2 TSE volumetric images and axial T1 GRE fat-sat without contrast, extracted from fMRI) and fMRI protocols randomly, with at least 4weeks interval between readings. The degree of confidence for diagnosis at each AS was evaluated with a 1-3 Likert Scale (1: low; 3: high). Intra- and inter-reader agreement between protocols were evaluated by kappa statistics and took reading experience into account. The gold standard for assessing the performance of imaging interpretation (sensitivity, specificity and accuracy) used a consensus reading of two other Rd (> 15 years experience). There was no significant difference in the accuracy of imaging interpretation between the abbreviated (0.83-0.86) and full (0.83-0.87) protocols (p = 0.15). Intra-reader agreement between protocols ranged from substantial to almost perfect (0.74-0.96). A substantial inter-reader agreement was found for both protocols for readers with similar levels of experience (0.67-0.69) and in the global analysis (0.66 for both protocols). No difference was found in terms of degree of confidence between protocols, for all readers. An abbreviated MRI protocol for pelvic endometriosis provided an accuracy of interpretation comparable to that ofa complete protocol, with similar degrees of confidence and reproducibility, regardless the level of experience.