Propranolol and Von Hippel-Lindau Disease

Inclusion Criteria: * Age ≥ 18 * VHL patient with one or more hemangioblastomas of the central nervous system, none of which require urgent surgery (within 3 months) * Patient with written consent to participate in the study * Enrolled in a social security plan or beneficiary Exclusion Criteria: * Contraindication to the use of propranolol: * chronic obstructive pulmonary disease and asthma, * uncontrolled heart failure, * 2nd and 3rd degree atrioventricular blocks, * bradycardia (\<50 beats/minute after 3 minutes of rest), * Raynaud's phenomenon and peripheral arterial disorders, * arterial hypotension, * hypersensitivity to propranolol * cardiogenic shock, * Prinzmetal's angina, * sinus disease (including sino-auricular block) * untreated pheochromocytoma, * history of anaphylactic reaction, * in the context of primary and secondary prevention of digestive bleeding in cirrhotics: advanced liver failure with hyperbilirubinemia, massive ascites, hepatic encephalopathy * predisposition to hypoglycemia (as after fasting or in case of abnormal response to hypoglycemia) * metabolic acidosis * Contraindication to MRI: * claustrophobia, * presence of a pace maker and other stimulators/implants * ocular metallic foreign bodies, * heart valves or ferromagnetic metal vascular clips * Patients already on Propranolol or other beta blockers * Patients under guardianship or conservatorship * Pregnant or breastfeeding women - Woman with a medium-term pregnancy project