title: Diagnostic accuracy of diffusion-weighted imaging in differentiating benign from malignant ovarian lesions.
abstract: OBJECTIVE
  To clarify the diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant ovarian lesions.
  
  
  METHODS
  We retrospectively analyzed magnetic resonance images of 123 ovarian lesions in 119 patients. We defined lesions with abnormal signal intensity as malignancy and assessed the location of abnormal intensity within the lesions on DWI. We also assessed the mean and lowest apparent diffusion coefficient (ADC) values of the solid portion for each ovarian lesion.
  
  
  RESULTS
  The majority of malignant ovarian tumors and mature cystic teratomas, and almost half of the endometriomas, showed abnormal signal intensity on DWI, whereas most fibromas and other benign lesions did not. The main locations of abnormal signal intensity were solid portions in malignant ovarian tumors, cystic components suggestive of keratinoid substances and Rokitansky protuberance in mature cystic teratomas, and intracystic clots in endometriomas. On DW imaging, receiver-operating characteristic analysis yielded mean Az values of 0.703. There was no significant difference in mean and lowest ADC values between malignant and benign lesions.
  
  
  CONCLUSIONS
  DWI of ovarian lesions and ADC values of the solid component are not useful for differentiating benign from malignant ovarian lesions. This knowledge is essential in avoiding misinterpretation in the diagnosis of ovarian lesions.
authors.affiliation: Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, Yonago, Japan. sfujii@grape.med.tottori-u.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Fujii
authors.forename: Suguru
authors.initials: S
authors.lastname: Kakite
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nishihara
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Kanasaki
authors.forename: Tasuku
authors.initials: T
authors.lastname: Harada
authors.forename: Junzo
authors.initials: J
authors.lastname: Kigawa
authors.forename: Toshio
authors.initials: T
authors.lastname: Kaminou
authors.forename: Toshihide
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008875:Middle Aged; D010051:Ovarian Neoplasms / Q000145:classification* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult