Imaging and BioFluid Biomarkers in Amyotrophic Lateral Sclerosis

Inclusion Criteria Study subjects meeting all of the following criteria will be allowed to enroll in the study: 1. Male or female, aged 18 to 80 2. Medically safe to undergo MRI scans 3. Able to safely lie supine for at least 90 minutes in the opinion of the Site Investigator 4. Capable of providing informed consent and following trial procedures 5. Geographically accessible to the site ALS subjects must also meet the following criteria: 1. Sporadic or familial ALS diagnosed as possible, laboratory-supported probable, probable, or definite as defined by modified El Escorial criteria 2. ALS Cognitive Behavioral Screen score \>10 on the cognitive scale and/or \>32 on the behavioral scale Those ALS subjects participating in the optional lumbar puncture portion of the study must also meet the following criteria: 1\. Subjects medically able to undergo lumbar puncture (LP) as determined by the investigator (i.e., no bleeding disorder, allergy to local anesthetics, a skin infection at or near the LP site, or evidence of high intracranial pressure). For those subjects participating in the PET scan portion of the study, subjects must also meet the following criteria: 1. Medically safe to undergo PET scans 2. No prior radiation exposure that exceeds the site's current guidelines 3. No known allergy to any components of the tracer 4. Baseline ECG values are within normal range 5. Subjects must meet main study entry criteria Exclusion Criteria Study subjects meeting any of the following criteria during screening evaluations will be excluded from entry into the study: 1. Any contraindication to undergo MRI studies such as 1. History of a cardiac pacemaker or pacemaker wires 2. Metallic particles in the body 3. Vascular clips in the head 4. Prosthetic heart valves 5. Claustrophobia 2. Diagnosis of Parkinson's disease or Alzheimer's disease 3. Diagnosis of renal failure 4. Have active or chronic autoimmune disease (such as hepatitis or HIV), infection, or taking immunosuppressive medications such as steroids, cyclophosphamide, etc. 5. Presence of diaphragm pacing system (DPS) 6. The presence of unstable psychiatric disease, cognitive impairment, or dementia that would impair ability of the subject to provide informed consent, according to SI judgment 7. Pregnant women or women currently breastfeeding 8. Anything that, in the opinion of the investigator, would place the subject at increased risk or preclude the subject's full compliance with or completion of the study In addition, any subject meeting any of the following criteria during screening evaluations will be excluded from entry into the PET portion of the study: 1. Radiation exposure that exceeds the site's current guidelines 2. Low affinity TSPO binders determined by having a Thr/Thr polymorphism in the TSPO gene (rs6971) at the Screening Visit Women of Childbearing Potential (WOCBP) For the purposes of this study, women of child bearing potential are defined as all women who are capable of becoming pregnant, unless they meet one of the following criteria: * 12-months post-menopausal * Post-hysterectomy * Surgically sterile