This is a patient on long term steroids with knee pain. MRI Knee shows infarcts/AVN in femur and tibia along with marrow edema. There is focal serpiginous low signal line with fatty center, which is characteristic.
For bone infarction or avascular necrosis, MRI is the most sensitive modality and demonstrates changes well before and plain film changes are visible. The progression is:
Knee-Avascular Necrosis-MRI Reviewed by Sumer Sethi on Monday, September 24, 2012 Rating: