MRI
Stigmata of previous core decompression is visible at both femoral heads.
On the right side: double-line sign of femoral head AVN with peripheral bone marrow edema. According to Shimizu et al. classification 2, the extent of femoral head necrosis is measured as less than 1/4 of femoral head diameter (grade A), involving more than 2/3 of the weight-bearing articular margin of the femoral head (grade B). Bone marrow shows mixed T1 signal intensity at the region of AVN (grade β).
On the left side: double-line sign of femoral head AVN with peripheral bone marrow edema. The extent of femoral head necrosis is measured between 1/4-1/2 of femoral head diameter (grade B), involving more than 2/3 of the weight-bearing articular margin of the femoral head ( grade C). Bone marrow shows low T1 signal intensity at the region of AVN (grade γ). Minimal surface collapse of the femoral head with early degenerative changes of the hip joint is noted.