Bone-Scanning for Diagnosis of AVN

Discussion

• for detection of AVN, technetium-99 methylene-diphosphonate bone-scanning is a useful technique;
  • bone-scanning may be less sensitive in the detection of AVN at early stage of the disease or when both hips are involved symmetrically;
• reactive of bone at the edge of the infarcted segment will show an increased uptake of the isotope on the delayed image;
• a photopenic area (cold area) located anterolaterally which is surrounded by an area of increased activity is most consistent w/ dx of avascular necrosis;
• diff dx
  • reflex sympathetic dystrophy
  • transient osteoporosis;
  • infection;
  • tumors