MRI in amyotrophic lateral sclerosis: hyperintensity of the corticospinal tract.

Amyotrophic lateral sclerosis is the most common form of motor neuron disease. The diagnosis is based on clinical and electromyography criteria. The primary role of imaging in amyotrophic lateral sclerosis is to exclude other causes such as cervical degenerative disk disease, Chiari malformation or multiple sclerosis. Imaging is also helpful in atypical cases of the disease.