Applicability of Magnetic Resonance Imaging for Early Diagnosis of Common Peroneal Neuropathy

Objective: This study aimed to assess the clinical applicability of magnetic resonance imaging (MRI) for the early diagnosis of common peroneal neuropathy (CPNe).Methods: Over three years, the authors have treated 58 patients with CPNe. All patients had clinical or neurophysiological confirmation of CPNe. Among them, 35 (60%) patients underwent axial knee MRI with a 1.5-Tesla scanner. These 35 patients were selected for study and were classified into three groups according to the time of examination after the occurrence of dropped foot―acute, subacute, and chronic onset groups. According to muscle appearances (normal, edematous change, and atrophy), we diagnosed them with CPNe, except for those with normal morphology. We evaluated the applicability of MRI in the diagnosis of CPNe compared to that of electromyography (EMG).Results: The 18, 11, and six cases were included in the acute, subacute, and chronic onset groups, respectively. In the acute onset group, three cases had normal muscle appearance, while 15 cases had edematous changes in the affected muscles. In the subacute onset group, eight cases had edematous changes, while three cases showed muscle atrophy. In the chronic onset group, six cases had muscle atrophy. CPNe could be diagnosed using MRI in about 91% (32/35) of all the cases. Excluding the chronologically chronic stage, diagnosis rate was approximately 89%(26/29) of all the cases. However, only in 27 cases (77%) denervation potentials were presented on EMG.Conclusion: According to our results, MRI is a helpful diagnostic modality, especially in the early stage of CPNe, and may lead to proper management.