Amyotrophic lateral sclerosis and primary lateral sclerosis: evidence-based diagnostic evaluation of the upper motor neuron

This article reviews neuroimaging findings related to motor neuron disease, specifically amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS). In addition to numerous reports concerning neuroimaging findings of these diseases on MR imaging, single-photon emission computed tomography, and positron emission tomography, many studies indicate the usefulness of MR spectroscopy in evaluation of the upper motor neuron deficit found in both of these disorders. A neuroimaging algorithm for the clinical evaluation of possible ALS and PLS is proposed, and the important role of neuroimaging studies in future therapeutic trials is discussed.