Ultrasound may help Alzheimer's drug reach the brain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Positive diagnosis of Alzheimer's disease according to IWG2 criteria * Biological profile in favour of Alzheimer's disease * Age ≥ 50 years and ≤ 85 years * Affiliated or beneficiary of a social insurance scheme * Patient suffering from mild AD with little or no impact on autonomy, MMSE score ≥20 at inclusion * Fazekas score \<=1 * Presence of a family or a person at home who can monitor the occurrence of adverse events * Sufficient command of the French language to take neuropsychological tests. * Have undergone a full neuropsychological assessment within 6 months. * If anticholinesterase treatment, stability of treatment for at least three months. * Signed, free and informed consent from the patient and the trusted support person. Exclusion Criteria: * Patient previously treated with anti-TNF alpha (e.g. etanercept). * Other cause of major neurocognitive disorder. * Participation in another drug study * Absolute contraindication to MRI (e.g. pacemaker, implantable stimulator, intra-orbital metallic foreign body); * Contraindication to lumbar puncture. * History of bleeding diathesis; * Severe chronic respiratory disease; * Patient on anticoagulant therapy * Right-to-left shunt, severe pulmonary arterial hypertension; * Known cerebral vasculopathy; (Fazekas greater than 1), sequelae of ACI. * Treatment with Anakinra, abatacept or sulfasalazine. * Patients who have undergone major surgery within 28 days of the first day of the study. * Allergy to gadolinium, or any contraindication to contrast products used for brain imaging (in particular severe renal insufficiency with a glomerular filtration rate \<30 ml / min / 1.73 m2). * Allergy to xylocaine * Epilepsy or drugs that lower the epileptogenic threshold (see Appendix 6). * Major depressive syndrome despite appropriate treatment and/or psychotic symptoms (according to DSM IV); * MRI characteristic of an active or acute neurological process (infection, tumour) or macro-haemorrhage. * Non-menopausal women * Patient benefiting from a legal protection measure other than guardianship or curatorship. * Optic neuritis * Manifestations of multiple sclerosis * Live vaccinations (yellow fever, BCG) within 4 weeks of starting etanercept treatment. * History of hepatitis B or C * Patients with recent acute coronary syndrome or unstable ischaemic heart disease. * History of recurrent or chronic infections, or a predisposing condition such as severe or poorly controlled diabetes. * Patients who have undergone major surgery within 28 days of the first day of the study. Contraindications related to etanercept : * Hypersensitivity to etanercept or to any of the excipients of Benepali * Sepsis or risk of sepsis * Active infection including chronic or localised infections. Contraindications associated with SonoVue (ultrasound contrast medium) * Hypersensitivity to Sonovue. * Right-to-left shunt * Severe PAH (pulmonary arterial pressure greater than 90 mmHg) * Uncontrolled hypertension * Respiratory distress syndrome * Conditions suggesting cardiovascular instability for which dobutamine is contraindicated