The Mr Features Of Bone Marrow Edema And Its Clinical Value In Femoral Head Necrosis

ObjectiveTo investigate the MRI features of bone marrow edema and visualize its clinical value in femoral head necrosis,to explore the differences between transient osteoporosis of the hip (TOH) and bone marrow edema (BME) associated with osteonecrosis of the femoral head in terms of clinical practice and imaging.Material and methodswe reviewed retrospectively the MR images of 38 consecutive patients with femoral head necrosis(FHN) and 5 patients with transient osteoporosis of the hip(TOH).In all cases,MRI was carried out using a 1.5T Signa HDe(GE). Fast spin echo(T1WI,T2WI,T2WI fat suppression or STIR)and Spin echo(T1WI) were obtained in the coronal and axial planes with 43 patients.we analyze the images of all the patients. we reviewed all the clinical information and plain radiographs and MR images of 43 patients at 3-12 months intervals.Result(1) The BME pattern was identified in only 1 hip(12.5%)of the 8 stageⅠhips in patients of femoral head necrosis(FHN),2 hips(11.1%) of the 18 stageⅡhips,22 hips(91.7%) of the 24 stageⅢhips and 3 hips (30%)of the 10 stageⅣhips,1 hip stage V was not identified BME pattern.(2) 61 hips of 38 patients was diagnosed FHN,26 hips(57%) of 46 hips with pain showed regional necrosis associated with bone marrow edema.but 2(13%) of 15 hips without pain showed bone marrow edema.(P<0.01).26 of 28 hips showed moderately or severely painful which was associated with bone marrow edema. Bone marrow edema involved the femoral head and neck and extended to the trochanteric area in 5 TOH patients.Conclusion(1) The initial MRI findings of specific FHN shows "band like" low signal intensity subchondral zones in the weight-bearing portion of the femoral head on T1WI,small or large ring-like lesions with homogeneous or inhomogeneous central areas,diffuse decreased signal intensity with a dark band,the presence of double line sign on T2WI in the early stage of FHN.(2) BME is not the initial MRI features of FHN.BME follows by painful hip,it is highly associated with the collapse of femoral head.The initial findings of FHN are not or scarcely showed BME.It seems that the structural damage of femoral head lead to the presence of BME and pain.(3) BME and joint fluid and pain were highly correlated in the hips.