title: Diffusion-weighted echo-planar MR imaging and ADC mapping in the differential diagnosis of ovarian cystic masses: usefulness of detecting keratinoid substances in mature cystic teratomas.
abstract: OBJECTIVE
  To elucidate whether apparent diffusion coefficient (ADC) values calculated from echo-planar diffusion-weighted MR imaging (EPDWI) are useful in the differential diagnosis of ovarian cystic masses.
  
  
  METHODS
  EPDWI was performed in 131 patients with ovarian cystic masses (54 mature cystic teratomas, 35 endometrial cysts, four other benign cysts, 14 benign neoplasms, and 24 malignant neoplasms). The areas of the highest signal intensity on EPDWI (b = 1000 seconds/mm(2)) and the lowest ADC values within the cystic component were evaluated.
  
  
  RESULTS
  On qualitative and quantitative analyses, mature cystic teratomas tended to show higher signal intensity and had areas of lower ADC values than endometrial cysts and other benign and malignant neoplasms (P < .005). In vitro scanning of the cystic contents of mature cystic teratomas confirmed that high signal on DWI or low ADC value was attributable to the keratinoid substance within the tumors. The difference in ADC between malignant and benign lesions were significant when mature cystic teratomas and endometrial cysts were included, but was not significant when they were excluded.
  
  
  CONCLUSIONS
  The ADC value may add useful information to the differential diagnosis of ovarian cystic masses in limited populations, such as those with mature cystic teratomas with a small amount of fat.
authors: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka 812-8582, Japan.
authors: Tomohiro
authors: T
authors: Nakayama
authors: Kengo
authors: K
authors: Yoshimitsu
authors: Hiroyuki
authors: H
authors: Irie
authors: Hitoshi
authors: H
authors: Aibe
authors: Tsuyoshi
authors: T
authors: Tajima
authors: Akihiro
authors: A
authors: Nishie
authors: Yoshiki
authors: Y
authors: Asayama
authors: Kunishige
authors: K
authors: Matake
authors: Daisuke
authors: D
authors: Kakihara
authors: Shuji
authors: S
authors: Matsuura
authors: Hitoo
authors: H
authors: Nakano
authors: Hiroshi
authors: H
authors: Honda
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010048:Ovarian Cysts / Q000175:diagnosis* / Q000601:surgery; D010051:Ovarian Neoplasms / Q000175:diagnosis* / Q000601:surgery; D011336:Probability; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013724:Teratoma / Q000175:diagnosis* / Q000601:surgery