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.
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.
Nakayama
Tomohiro
T
Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka 812-8582, Japan.
Yoshimitsu
Kengo
K
Irie
Hiroyuki
H
Aibe
Hitoshi
H
Tajima
Tsuyoshi
T
Nishie
Akihiro
A
Asayama
Yoshiki
Y
Matake
Kunishige
K
Kakihara
Daisuke
D
Matsuura
Shuji
S
Nakano
Hitoo
H
Honda
Hiroshi
H
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