MR Evaluation of Pyo genic Osteomyelitis Involving the Epiphyses

ABSTRACT

PURPOSE: The purpose of this study was to analyze of the MR findings of the pyogenic osteomyelitis involving the epiphyses of the long bones in childhood. MATERIALS AND METHODS: Eleven childen with pyogenic osteomyelitis involving the epiphyses of the long bones were evaluated by MRI. A diagnosis of pyogenic osteomyelitis was established by biopsy and culture in eight cases and during follow-up after antibiotic treatment in three. We analyzed the involved bone, initial location, pattern, degree of growth plate involvement, degree of epiphyseal involvement, surrounding change and plain radiographic findings. RESULTS: The involved bones were the proximal femur in four cases, distal femur in two, proximal tibia in two, distal tibia in one, distal fibula in one and proximal humerus in one. The initial site of the lesion was the metaphysis in ten cases and epiphysis in one. The lesion pattern was the Brodie's abscess in six cases and osteomyelitis in five. The degree of growth plate involvement was 16-20% in five case and 5% or less in four ; the degree of epiphyseal involvement was 5% or less in four cases, 6-10% in four and 11-15% in two. All cases showed low or intermediate signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and contrast enhancement. Joint effusion adjacent to the lesion was detected in five cases. Radiographic findings of the involved epiphysis were normal in six cases, but indicated osteolytic lesion in four cases and sclerosis in one. CONCLUSION: Pyogenic osteomyelitis involving the epiphyses of the long bones in childhood usually developed from metaphyseal osteomyelitis and was combined with destruction of the growth plate.