What is the differential diagnosis of endometrioma ?
1. hemorrhagic cysts also appear hyperintense on T1-weighted images, but typically do not have T2 shading (they are typically bright on T2-weighted images) and T2 dark spot 2. ovarian dermoid cysts also appear hyperintense on T1-weighted images, but signal loss on fat-saturated sequences 3. cystic neoplasms show heterogeneous T1 signal and enhancement 4. tubo-ovarian abscess presents as a T1 hypointense lesion and T2 heterogeneous to hyperintense signal, with wall and surrounding soft tissue enhancement
How to describe the T2 dark spot sign ?
T2 dark spot sign is defined as a hypointense focus on T2-weighted images. It is a marker of chronic haemorrhage (haemosiderin-laden macrophages and fibrous component).