The value of combined radionuclide and magnetic resonance imaging in the diagnosis and conservative management of minimal or localized osteomyelitis of the foot in diabetic patients

Early diagnosis of osteomyelitis is helpful for a successful conservative t reatment. The value of bone scanning combined with granulocytes labeled wit h hexamethylpropylene amine oxime (HMPAO) granulocyte-Tc99m (GN) radionucli de imaging (combined [RI]) with magnetic resonance imaging (MRI) for the di agnosis of osteomyelitis was assessed in 24 diabetic patients with foot ulc ers. Evidence of osteomyelitis was based on the presence of at least one of the following criteria: (1) clinical bone involvement, (2) radiological bo ne involvement, (3) both positive combined RI and MRI, and (4) evidence of clinical bone involvement during the follow-up period. Thirteen patients ha d osteomyelitis. Seven patients had clinical bone involvement (sensitivity, 54%), five had radiological bone involvement (sensitivity, 38%), and 10 ha d positive combined RI for osteomyelitis (sensitivity, 77%). MRI demonstrat ed a higher sensitivity (100%). The specificity for combined RI and MRI was 82%. These results lead to a new diagnostic strategy for the early detecti on of minimal or localized osteomyelitis to avoid amputations. MRI is most appropriate following a negative x-ray in determining whether to treat oste omyelitis, since a negative MRI result rules out osteomyelitis. Antibiotic therapy should be used in the case of a positive MRI result, but Charcot jo int disease can lead to false-positive MRI results. In this case, combined RI should be performed. Copyright (C) 1999 by W.B. Saunders Company.