What sign is seen in the medullary space of the tibia and calcaneus? What does it represent?
Double line sign of avascular necrosis.
List the various causes of avascular necrosis.
Use the mnemonic: PLASTIC RAGS P - pancreatitis L - lupus A - alcohol S - steroids T - trauma I - idiopathic, infection C - caisson disease, collagen vascular disease R - radiation, rheumatoid arthritis A - amyloid G - Gaucher disease S - sickle cell disease
There are irregular, serpiginous lines of low T1 and STIR signal intensity observed within the medullary space of the distal tibia and posterior calcaneus. On STIR, there is a hyperintense line pralleling the inner surface of the hypointense line within the marrow.