Multicenter ALS Imaging Study

This is a multi-site study of ALS participants and healthy controls who will undergo brain and cervical spine MRIs and NfL blood testing at up-to 4 time points over the course of a year. The primary goal is to identify objective biomarkers of disease progression that are biologically relevant, linearly progressive, and sensitive to change.

For participants with ALS: * \< 36 months since onset of symptoms * Definite, probable, lab-supported probable, or possible ALS by El Escorial criteria OR definite, probable, or possible ALS per Awaji-Shima criteria OR meets Gold Coast criteria * Forced vital capacity within the last 90 days ≥ 60% of the predicted value * Able to consent for themselves * Able to read and speak English * Clear of any contraindications for MRI Exclusion Criteria: * Individuals will be excluded if they have any condition that makes MRI unsafe or if they are unable to comply with instructions. * All participants will undergo a neurologic examination at enrollment. Control participants with clinically significant abnormal findings on neurological examination will be excluded from the study.