- 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