Table 1 Incidence and appearance of morphological features and signs of ovarian teratomas in different imaging modalities
From: Mature cystic teratoma of the ovary: a cutting edge overview on imaging features
Imaging feature/ sign | Incidence | US | CT | MRI |
|---|---|---|---|---|
Rokitansky nodule (dermoid plug) | Shadowing echodensity: a densely echogenic tubercule projecting into the cystic lumen | A rounded structure protruding into to the cystic lumen, mural thickening, a bridge across the cyst, a cystic structure or sometimes only tooth | A rounded structure protruding into to the cystic lumen, mural thickening, a bridge across the cyst or a cystic structure | |
Tip of the iceberg sign | 4% [7] | Mixture of fatty fluid, hair and cellular debris creating an echogenic focus with acoustic shadowing behind it | ||
Dot-dash sign | 61% [5] | Hyperechoic lines and dots arising from hairs in different orientations within the imaging plane | ||
Fat-fluid / fluid-fluid level | Anechoic sebum layered above hyperechoic aqueous/debris containing layer or less frequently, supernatant hyperechoic sebum layer above hypoechoic aqueous fluid | Supernatant fatty layer with lower attenuation and dependent fluid layer with higher attenuation | High SI of supernatant fatty layer on T1-W images and low SI on fat-suppressed T1-W images | |
Floating balls sign | Uncommon [4] | Intracystic floating hyperechoic globules moving with changing position of the patient | Floating globules in gravity- independent position within the cyst fluid or in the interface of fat- fluid level | Floating globules in gravity- independent position within the cyst fluid or in the interface of fat-fluid level |
Comet tail appearance | 12% [7] | Hypoechoic hair balls with posterior acoustic shadowing | ||
Intratumoral fat | 93% [6] | Diffuse or regional high amplitude echoes | A component with density between −144 and −20 HU in Rokitansky nodule or cyst wall, a layering component or a floating mass mixed with hair | A component with high SI on T1-W images and signal drop on fat-saturated T1-W images |
Tooth/ calcification | 56% [6] | Regional high amplitude echoes with shadowing | Curvilinear or globular calcification in the Rokitansky nodule, in the tumour wall or in/near the septa | |
Chemical shift artefact | 86% [8] | Foci or areas of very high SI on T2-W images or a boundary artefact with high and low SI bands on opposite sides of the tumour | ||
Tuft of hair | 65% [6] | Diffuse or regional high amplitude echoes | A component with chemical shift artefact in the gravity-dependent part of the cyst | |
Palm tree-like protrusion | 21% [8] | Polipoid mass protruding into cyst cavity with internal pattern resembling a palm tree | ||
Intratumoral keratinoid material | 75% [9] | A component with low SI on T1-W and high SI on T2–W images and diffusion restriction |