Electromyography and magnetic resonance imaging in the evaluation of radiculopathy

Electromyography (EMG) and magnetic resonance imaging (MRI) are commonly used in the diagnosis of cervical and lumbosacral radiculopathy, but the agreement between the two studies is unknown. We retrospectively studied 47 patients with a clinical history compatible with either cervical or lumbosacral radiculopathy who were evaluated with both an EMG and a spine MRI within 2 months of each other. Among these patients, 55% had an EMG abnormality and 57% had an MRI abnormality that correlated with the clinically estimated level of radiculopathy. The two studies agreed in a majority (60%) of patients, with both normal in 11 and both abnormal in 17; however, only one study was abnormal in a significant minority (40%), suggesting that the two studies remain complementary diagnostic modalities. The agreement was higher in patients with abnormal findings on neurologic examination, underscoring the difficulty of confirming the diagnosis in mild radiculopathy.