Bone infarct

Tumor biology and incidence

• Localized area of bone with avascular necrosis
• Conditions associated with bone infarction:
  • Trauma
  • Alcohol
  • Steroids
  • Working in conditions requiring air compression and decompression (deep see diving, caisson workers )
  • Gaucher's disease
  • Sickle cell disease
  • Gout
• Bone infarction involving articulating ends of long bones (femur, humerus) or weight-bearing bones (talus) usually found early due to pain or joint involvement
• Bone infarction involving metaphysis or diaphysis generally asymptomatic
  • Remain undetected until incidentally found or if patient experiences pathologic fracture or sarcomatous degeneration

Plain films

Size

Variable

Tumor effect on bone

• Irregularly serpiginous-shaped calcified periphery possible
• Patchy sclerosis ans lucency possible
• Linear densities generally appear within the lesion

Cortex

If cortex involved, spares outer one third while affecting inner two thirds

MRI

• May be diagnostic
• May see central marrow fat within the lesion
• May see classic "double ring" sign
  • Manifests as an inner serpiginous margin of lower T2-weighted signal and adjacent outer ring of high T2-weighted signal intensity