Role of Magnetic Resonance Imaging in Diabetic Foot: A Cross-sectional Study

Introduction: Diabetes related foot problems like osteomyelitis and Charcot (neuro-osteoarthropathy) are associated with high morbidity and high healthcare costs. Soft tissue and bone infection involving the foot is particularly common in patients with diabetes mellitus. Osteomyelitis and neuropathic osteoarthropathy often co-exists in diabetes. Differentiating between these two entities is often difficult but crucial as the management may differ significantly.

Aim: To assess the role of Magnetic Resonance Imaging (MRI) in diabetic foot and its ability to identify features which help to reliably differentiate infection from neuropathy and to describe the MRI imaging findings of infection and neuropathic changes in diabetic foot.

Materials and Methods: The present cross-sectional study was conducted in Amrita Institute of Medical Sciences and Research Centre, Kochi, Kerala, India, from June 2013 to October 2015. All diabetic patients with suspected osteomyelitis or charcot who were referred for MRI were included. MRI was interpreted based on the following parameters location, distribution of oedema pattern, deformity, soft tissue changes and bone marrow signal change. Forty eight patients with diabetic foot, who underwent foot surgery with debridement or drainage and MR findings of the patient were compared with histopathology or culture respectively. Comparison of MR findings were also done with Computed Tomography (CT)/Positron Emission Tomography (PET) wherever available.

Results: In this study, MRI findings with focal single bone involvement along with diffuse marrow oedema pattern, absence of deformity, forefoot/hindfoot location, presence of soft tissue changes like ulcer/sinus tract/fistulas and abscess formation were in favour of osteomyelitis. Several bones and joints involvement along with subchondral/periarticular location, presence of deformity, absence of soft tissue changes and midfoot location were in favour of Charcot’s.

Conclusion: The MRI was found to be the most reliable and sensible tool for imaging techniques to differentiate osteomyelitis with diabetic neuropathic arthropathy, with the sensitivity and specificity of MRI as 83.3% and 77.8%, respectively.