Clinical, electromyographic, and ultrasonographic assessment of focal neuropathies

The study was intended to evaluate the diagnostic value of muscle ultrasonography in the diagnosis of focal neuropathy. Two hundred four patients with possible unilateral injury to nerve roots, plexuses, and nerves extremity were examined prospectively by means of manual muscle testing, electromyography (EMG), and muscle ultrasonography. These findings were compared with those of 36 control subjects. Pathologic spontaneous activity correlated very closely with abnormal ultrasonographic findings, especially with increased muscular echointensity. Ultrasonography was as sensitive as manual muscle testing and EMG in the detection of muscle involvement. Ultrasonography and EMG were complementary. In about 15% of muscles, only one of the two techniques revealed pathologic findings. Increased muscle echointensity was seen in 79% and muscle atrophy in 48% of muscles assessed to be abnormal. The first ultrasonographic abnormalities appeared 10 days and pathologic spontaneous activity 18 days after acute injury. Ultrasonography was slightly but significantly less reliable than EMG. Muscle ultrasound can help in visualizing anatomic abnormalities such as muscle atrophy and mesenchymal abnormalities in nerve root, plexus, and nerve lesions.