Grading of avascular necrosis of the femoral head and early imaging diagnosis

Objective: To study the staging and early imaging diagnosis of avascular necrosis of the femoral head (ANFH). Methods: X-ray, CT, and low-field MRI were conducted and grading was performed in bilateral femoral head of 62 cases. Rank sum H test and sensitivity were completed. Results: The entire cases were diagnosed as early ANFH by X-ray film in 91 places. Stage I showed osteoporosis and osteosclerosis in 46 places. Stage II showed osteosclerosis and cystic hyalomere in 45 places. 56 cases of early ANFH were discovered by CT in 86 places. Stage I showed stelliform sign distortion and osteoporosis and osteosclerosis in 34 places. Stage II showed osteosclerosis and cystic hyalomere in 30 places. Stage III showed meniscus sign in 22 places. Low-field MRI displayed only 44 cases (73 places) of early ANFH. Stage I displayed the macular shape low or high signal intensity on Tl weighted and GRL image in 30 places. Stage II displayed the irregular shape low or equal or high signal on Tl weighted and GRL image in 23 places. Stage III displayed the flaky low signal and curve high signal on Tl weighted and GRL image in 20 places. Rank sum H test and sensitivity compare were striking (P < 0.01). Conclusions: CT and low-field MRI could exactly display early ANFH. Sensitivity and diagnostic value of low-field MRI is superior to CT and X-ray film