Correlation at imaging techniques to histopathology in patients with diabetic foot syndrome and clinical suspicion of chronic osteomyelitis - The role of high-resolution ultrasound

OBJECTIVE - To investigate the role of ultrasound in the diagnosis of osteo myelitis in the diabetic foot compared with magnetic resonance imaging (MRI ), bone scintigraphy (BS), and plain film radiography (PFR). RESEARCH DESIGN AND METHODS - We investigated 19 consecutive diabetic patie nts (2 women, 17 men, age 60.7 +/- 9.8 years, BMI 27.0 +/- 3.8 kg/m(2)) wit h clinical suspicion of bone infection of the foot. A high-resolution ultra sound system (Esaote/Biosound, Munich) with a linear array transducer up to 13.0 MHz was used. The prospective and blinded results of each method were compared with histopathology as the reference method after metatarsal rese ction. RESULTS - In 14 of 19 patients, histopathology confirmed osteomyelitis. Ult rasound showed a sensitivity of 79% (PFR, 69%; BS, 83%; MRI, 100%), a speci ficity of 80% (PFR, 80%; BS, 75%; MRI, 75%), a positive predictive value of 92% (PFR, 90%; BS, 91%; MRI, 93%), and a negative predictive value of 57% (PFR, 50%; BS, 60%; MRI, 100%). CONCLUSIONS - Our data indicate that ultrasound might have a better diagnos tic power for detecting chronic osteomyelitis in the diabetic foot than PFR and has similar sensitivity and specificity as BS. MRI is superior to the other three methods. We conclude that the use of ultrasound in the manageme nt of the diabetic foot is worthy of further investigation.