Neuronavigation-guided FUS-induced BBB Opening in Alzheimer's Disease Patients and Its Effects on Brain Amyloid and Tau

Inclusion Criteria. AD patients will be recruited in person and have to be over 50 years of age and able to give consent. Patients diagnosed with MCI or AD will be included in our study. Other more severe symptomatic patients will be eligible to enroll, as long as they have the ability to consent for their participation. Screening is essential and will be performed by our collaborator and neurologist of the study, Dr. Lawrence Honig, MD at the Taub Institute of Alzheimer's Disease and Aging at Columbia. After the initial screening we will acquire MRI scans as part of the study and finalize enrollment or exclusion of the patient. Inclusion criteria thus include: * Age greater than 50 years old. * Diagnosis of MCI or AD. All following criteria must be met: * MMSE score between 12 and 26. * Modified Hachinski Ischemia Scale (MHIS) score of \<= 4 * Short form Geriatric Depression Scale (GDS) score of \<= 6. * PET scan confirming amyloid plaque load using Amyvid (18F-Florbetapir). * PET scan confirming tau positivity in the frontal lobe using MK-6240 (F18-Florquinitau). * Ability to provide informed consent. Exclusion Criteria. Exclusion criteria include surgeries and other pathologies not associated with AD, as outlined in the following list: * Prior administration of any amyloid-reducing agent such as aducanumab or lecanemab. * Contraindication for MRI. * Contra-indication history or hypersensitivity to MRI contrast agents (e.g., Dotarem) or microbubbles (e.g., Definity, Luma…