MRI and Technetium-99m Hexamethylpropylene Amine Oxime Labeled Leucocyte Scintigraphy in the Diagnosis and Differentiation between Acute Osteomyelitis and Neuroarthropathy in the Diabetic Foot

Abstract Background: Soft tissue and bone infection and neuro osteoarthropathy involving the foot are the most common long-term complications of diabetes mellitus, implying a serious impairment in quality of life for patients in the advanced stages of the disease. Both pathologies often coexist and differentiating between them is crucial because the management may differ substantially. Misdiagnosis may result in high morbidity for the patient such as unnecessary limb amputation. Diagnosis is largely based on clinical signs supplemented by various imaging modalities such as radiography, MR imaging, and hybrid imaging techniques such as F-18 fluorodeoxyglu-cose-positron emission tomography and nuclear imaging studies. Aim of Study: The aim of this study is to evaluate the diagnostic value of MRI and technetium-99m Hexamethyl-propylene Amine Oxime (HMPAO) labeled leukocyte scin-tigraphy in the diagnosis and differentiation between acute osteomyelitis and neuroarthropathy in the diabetic foot. Patients and Methods: The study included 35 patients (20 men and 15 women) aged 62±8.8 years having diabetes mellitus and a total of 43 clinically suspicious infection sites. The basic exploration included standard radiography, three-phase bone scintigraphy and 99mTc-HMPAO Leucocyte Scan (HMPAO-LS) and pre and post contrast enhanced MRI. 16 bone and 10 soft tissue biopsies were obtained from ulceration sites. Clinical follow-up as well as scintigraphy and MRI performed 4 months after initial diagnosis and 1 month after antibiotic withdrawal were performed in suspected osteomy-elitis cases. Results: Among the 43 sites, 23 sites were finally diag-nosed as osteomyelitis. No osteomyelitis was present at 20 sites, of which 9 sites were diagnosed as cellulitis and 11 as neuropathic ulcers based on combined clinical, imaging, pathologic findings and follow-up. The sensitivity and specif-icity of MRI were (95% and 85%) and of Labeled leucocyte scanning were (87% and 90%) respectively.
Conclusion: The combined use of 99mTc-HMPAO-LS and MRI yielded higher diagnostic efficacy in diabetic foot related complications.