ExAblate Blood-Brain Barrier (BBB) Disruption for the Treatment of Alzheimer's Disease

Inclusion Criteria: 1. Male or Female between 50-85 years of age 2. Probable Alzheimer's Disease (AD) 3. If taking concurrent Alzheimer's medication, has been on the medication for at least 2 months with a stable dose for at least 3 months 4. Able to communicate sensations during the ExAblate MRgFUS procedure 5. Ambulatory Exclusion Criteria: 1. MRI Findings 2. Presence of unknown or MR unsafe devices anywhere in the body 3. Significant cardiac disease or unstable hemodynamic status 4. Relative contraindications to ultrasound contrast agent or PET amyloid tracer 5. History of a bleeding disorder 6. History of liver disease 7. Known cerebral or systemic vasculopathy 8. Significant depression and at potential risk of suicide 9. Any contraindications to MRI scanning 10. Any contraindication to lumbar puncture for collection of cerebral spinal fluid 11. Untreated, uncontrolled sleep apnea 12. History of seizure disorder or epilepsy 13. Severely Impaired renal function 14. Currently in a clinical trial involving an investigational product or non-approved use of a drug or device or in any other type of medical research 15. Chronic pulmonary disorders 16. Positive human immunodeficiency virus (HIV) 17. Known apolipoprotein E allele (ApoE4) homozygosity