Structured manual for MRI assessment of deep infiltrating endometriosis using the ENZIAN classification

Purpose Proposal of a systematic approach to assess Deep infiltrating endometriosis (DIE) through pelvic Magnetic resonance imaging (MRI) using the Enzian classification and examination of inter-rater agreement. Methods Three radiologists reviewed 23 MRI of patients with pelvic DIE at one tertiary referral center retrospectively and independently. Inclusion criteria were intraoperative confirmation of DIE and MR imaging according to ESUR (European Society of Urogenital Radiology) guidelines. Assessment of the anatomical pelvic compartments was performed using a manual based on the Enzian classification with step-by-step instructions using recommended planes and sequences presented here. Interrater agreement was measured using kappa statistics. Results According to the intraoperative site lesions in 53 anatomical compartments were present. Interrater agreement was best for compartments A (0.255) and FB (0.642). For FI (0.204) and B (0.146) it was slight, there was poor agreement for C (− 0.263), FA (− 0.022), and FO (− 0.030), respectively, and as for FU, no ureter infiltration was described. Conclusion MRI as a noninvasive diagnostic tool offers essential advantages regarding classification and therapy planning for patients with DIE. However, its assessment is difficult and a more systematic approach is needed. Our proposed manual based on the Enzian classification is reproducible and could support radiologists and gynecologists.