Rim sign (osteonecrosis)

Last revised by Henry Knipe on 31 Aug 2022

A rim sign can be seen in osteonecrosis and comprises a high T2 or intermediate T1 signal line sandwiched between two low signal lines, and represents fluid between the sclerotic borders of an osteochondral fragment, and implies instability (stage III).

This rim sign should not be confused with the double line sign of osteonecrosis.

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