Diagnosis of pelvic endometriosis: a preliminary study on the added value of R2*MFGRE sequence in magnetic resonance imaging

Background Identifying and locating endometriotic lesions is crucial for preoperative planning, so new magnetic resonance imaging (MRI) techniques are urgently needed to improve the diagnostic sensitivity for pelvic endometriosis. Purpose To evaluate the feasibility of R2* multiple fast gradient recalled echo (MFGRE) imaging in the diagnosis of pelvic endometriosis. Material and Methods A total of 46 patients with suspected endometriosis underwent routine pelvic MRI and R2*MFGRE imaging. Clinical diagnosis was pathologically confirmed one month after MRI examination. Three radiologists who were blinded to the pathological results evaluated the number of ovarian endometriomas (OMAs) and deep infiltrating endometriosis (DIE) lesions using routine MRI and its combination with R2*MFGRE. The diagnostic sensitivity for OMA or DIE using the two examination methods was determined. Two-correlation sample rank-sum tests were used to compare both methods. Additionally, for all lesions, the R2* values were measured and statistically analyzed. Results Among 46 patients, 47 OMAs and 30 DIE lesions were found surgically and pathologically confirmed. The diagnostic sensitivity of the routine MRI was 87.2% for OMA and 46.7% for DIE. The diagnostic sensitivity of the routine imaging combined with R2*MFGRE was 100% for OMA and 90% for DIE. The two-correlation sample rank-sum test showed a significant difference between both methods (P<0.01, z = -4.26). The median R2* value was 25.20 (IQR=14) for the OMA group, and 45.21 (IQR=40) for the DIE group. The difference between both groups was statistically significant (P<0.01, z = -4.89). Conclusion R2*MFGRE imaging, as a supplement to the routine MRI, could improve the diagnostic sensitivity for pelvic endometriosis, especially for DIE.