The efficiency of susceptibility-weighted MRI in the differentiation of endometriomas from haemorrhagic ovarian cysts

The aim of the study was to investigate the efficiency of susceptibility-weighted magnetic resonance (MR) imaging (SWIs) in differentiating endometriomas from haemorrhagic ovarian cysts. Between July 2017 and January 2019, 89 ovarian cystic lesions (57 endometriomas and 32 haemorrhagic cysts) that were identified as complicated cystic lesions on ultrasonography (US) and underwent lower abdominal MRI with susceptibility weighting were retrospectively evaluated. Final diagnoses were obtained with surgical pathological correlation and radiological-clinical follow-up. Two radiologists blinded to the final diagnoses retrospectively reviewed the images in consensus. The signal intensity on T1- and T2-weighted images and curved linear or punctate signal void areas on SWI were noted for the presence of lesions. Forty of the 57 endometriomas demonstrated the defined MRI criteria, including a cystic hyperintensity on T1-weighted images and hypointensity on T2-weighted images. The remaining 17 lesions did not demonstrate these criteria on conventional MR images. SWI showed punctate or curved linear signal void areas in 53 of 57 endometriomas (92.9%) and none of the haemorrhagic cysts. The sensitivity, specificity and accuracy of SWI in differentiating endometrioma from haemorrhagic cyst were 92.9%, 100.0%, and 95.5%, respectively. The addition of the SWI sequence to conventional MRI can help distinguish endometriomas from haemorrhagic ovarian cysts.