title: Diffusion-weighted magnetic resonance imaging in the differentiation of endometriomas from hemorrhagic cysts in the ovary.
abstract: BACKGROUND
  The classic magnetic resonance imaging (MRI) feature of endometriomas is the shading sign, which is characterized by T2-shortening in ovarian cystic lesions that are hyperintense on T1-weighted images. The shading sign is infrequently observed in hemorrhagic ovarian cysts.
  
  
  OBJECTIVE
  To investigate the value of MRI with diffusion-weighted imaging (DWI) for distinguishing endometriomas from hemorrhagic cysts in the ovary.
  
  
  METHODS
  This retrospective study included 91 patients with 98 ovarian endometriomas and 21 hemorrhagic ovarian cysts that were confirmed pathologically, who had undergone MRI with DWI. Two radiologists compared MRI features, including size, bilaterality, multilocularity, the shading sign, the ovarian lesion/muscle signal intensity ratio at T2-weighted images, and T2 dark spots, between endometriomas and hemorrhagic cysts. We also compared the mean ADC value between endometriomas and hemorrhagic cysts, and determined the optimal cutoff ADC value for differentiating endometriomas from hemorrhagic cysts.
  
  
  RESULTS
  The size and mean ADC values were significantly different between endometriomas and hemorrhagic cysts. The mean ADC values of endometriomas and hemorrhagic cysts were 1.06 ± 0.38 × 10 (-3) mm(2)/s and 0.73 ± 0.29 × 10(-3) mm(2)/s, respectively (P < 0.002). The optimal cutoff ADC value for differentiating endometriomas from hemorrhagic cysts was 0.849 × 10(-3) mm(2)/s (sensitivity, 77.6%; specificity, 76.2%).
  
  
  CONCLUSIONS
  The addition of DWI could help in differentiating endometriomas from hemorrhagic cysts in the ovary, when conventional MRI is challenging.
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Nam Kyung
authors.initials: NK
authors.lastname: Lee
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea kimsuk@medimail.co.kr.
authors.forename: Suk
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Ki Hyung
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Obstetrics and Gynecology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Suh
authors.affiliation: Department of Radiology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan, Republic of Korea.
authors.forename: Tae Un
authors.initials: TU
authors.lastname: Kim
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Ga Jin
authors.initials: GJ
authors.lastname: Han
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Radiology, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors.forename: Jin You
authors.initials: JY
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D016889:Endometrial Neoplasms / Q000000981:diagnostic imaging*; D004715:Endometriosis / Q000000981:diagnostic imaging*; D005260:Female; D006470:Hemorrhage / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D010048:Ovarian Cysts / Q000000981:diagnostic imaging*; D012189:Retrospective Studies
keywords: Ovary; magnetic resonance diffusion; magnetic resonance imaging (MRI)