Imaging Biomarkers in ALS

Inclusion Criteria: * 21 to 75 years of age inclusive. * Willing and able to give signed informed consent that has been approved by the Institutional Review Board (IRB). ALS patients: * A clinical diagnosis of possible, laboratory-supported probable, probable, or definite ALS, according to a modified El Escorial criteria. Exclusion Criteria: * Diagnosis of other neurodegenerative diseases (Parkinson disease, Alzheimer disease, etc). * Clinically significant history of unstable medical illness (unstable angina, advanced cancer, etc) over the last 30 days. * Inability to undergo MRI scanning, including but not limited to unable to remain still in an MRI scanner for more than 30 minutes, claustrophobia, presence of paramagnetic substances or pacemakers in body, weight over 300 lbs, or in the opinion of the investigator, if there is a strong likelihood that the subject would not be able to lie flat comfortably for 75-90 minutes. * The subject requires assistance to ambulate OR climb stairs, unless in the opinion of the investigator, and based upon the subject's rate of disease progression, the subject is likely to be able to participate in the MRI screening 12 months after enrollment.