The International Ovarian Tumor Analysis (IOTA) group ultrasound rules for ovarian masses are a simple set of ultrasound findings that classify ovarian masses into benign, malignant or inconclusive masses. These rules apply to masses that are not a classical ovarian mass (e.g. corpus luteum, endometrioma, dermoid cyst), which have pathognomonic imaging features.
On this page:
Classification
Masses can be classified as either benign or malignant using simple ultrasound features. Ovarian masses that cannot be classified (~25% of ovarian masses) into either group are classified as "inconclusive" (either having none or both benign and malignant features) and further evaluation by a specialist in ovarian imaging is recommended.
Benign features
If an ovarian lesion has at least one of these features and no malignant features it can be confidently considered benign 1:
- unilocular cyst
- smooth multilocular tumor <10 cm
- solid components <7 mm in diameter
- presence of acoustic shadows
- no detectable Doppler signal
Malignant features
If an ovarian lesion has at least one of these features and no benign features it can be confidently considered malignant 1:
- irregular solid tumor
- irregular multilocular-solid mass >10 cm in diameter
- ≥4 papillary structures
- ascites
- high Doppler signal (color score 4)
Treatment and prognosis
When the rules can be applied (~75% of masses), there is a sensitivity of ~90% and a specificity of ~95%, which is similar to subjective expert evaluation 1.
Unable to process the form. Check for errors and try again.