O-RADS MRI risk stratification and management system

O-RADS MRI scoreRisk categoryPositive predictive value for malignancyRemarks
0Incomplete evaluation
1Normal ovariesNo ovarian lesion
Simple cyst < or equal to 3 cm in premenopausal women
Hemorrhagic cyst < or equal to 3 cm in premenopausal women
Corpus luteum with or without hemorrhage < or equal to 3 cm in premenopausal women
2Almost certainly benign< 0.5%Cyst: unilocular, any type of fluid content. No wall enhancement. No enhancing solid tissue
Cyst: unilocular, simple or endometriotic fluid content. Smooth enhancing wall. No enhancing solid tissue
Lesion with lipid content. No enhancing solid tissue
Lesion with dark T2 or DWI solid component. Homogeneously hypo intense in both T2 and DWI
Dilated fallopian tube – simple fluid content. Thin smooth walls with enhancement. No enhancing solid tissue
Para-ovarian cyst: any type of fluid. Thin, smooth wall enhancement. No solid enhancing tissue
3Low riskAround 5%Cyst: unilocular – proteinaceous, hemorrhagic or mucinous fluid content. Smooth enhancing wall. No enhancing solid tissue
Cyst: multilocular, any type of fluid. No lipid content. Smooth septa and wall with enhancement. No enhancing solid tissue. 
Lesion with solid tissue. Low risk curve on DCE MRI. 
Dilated fallopian tube. Non simple fluid – thin walls. Simple fluid with thick walls. No enhancing solid tissue
4Intermediate riskAround 50%Lesion with solid tissue. Intermediate risk curve on DCE MRI. Solid tissue enhancing less than myometrium
Lesion with lipid content. Large volume enhancing solid tissue 
5High riskAround 90%Lesion with solid tissue. High risk curve on DCE MRI. Tissue enhancing >myometrium at 30-40s