Characterization of Peri-Hemorrhagic Cerebral Edema Using Synthetic Sodium Imaging With 7-Tesla and 3-Tesla MRI

Intracerebral haemorrhage is the type of stroke with the highest mortality rate, estimated at 40% in the acute phase. Among survivors, half will experience functional disability. Currently, there is no validated effective treatment. Reduction of perihematomal oedema is a potential therapeutic target. The development of oedema in the days following the haemorrhage worsens functional prognosis, notably through a harmful inflammatory process. In the early phase, neuronal excitotoxicity induced by the hematoma plays a major role in triggering the inflammatory cascade. This phenomenon is associated with dysfunction of neuronal Na⁺/K⁺ ATPase pumps and a disturbance of cerebral sodium homeostasis. Ultra-high field 7T MRI enables in vivo quantification of brain sodium concentrations. We hypothesize that a drop-in sodium concentration within the perihematomal oedema is associated with greater oedema expansion and poorer functional outcome. To make this biomarker accessible to centers without 7 Tesla MRI, we will use an artificial intelligence algorithm to generate synthetic sodium concentration maps derived from data acquired on conventional 3 Tesla MRI.

Inclusion Criteria: * Patients aged between 18 and 80 years old; * presenting for a first-ever or recurrent symptomatic supratentorial spontaneous ICH within 8 (±2) days after symptoms onset (or last seen well) and confirmed by brain imaging; presumed to be related to small vessel disease. * Patient/legal representative/trusted person who has given written consent to participate in the trial; * Patient covered by social security in France * Patient willing to comply with all study procedures and its duration Exclusion Criteria: * Contra-indication for MRI; * pre-admission disabilities (mRs \> 4); * large ICH of 60 ml or more; * NIH Stroke Scale score \> 20; * item 1a of NIH Stroke Scale (level consciousness) \> 0; * surgical evacuation of ICH, associated intraventricular haemorrhage; ICH due to preceding trauma; ICH suspected to result from an identified intracranial vascular malformation, intracranial venous thrombosis, tumor or haemorrhagic transformation within an infarct. * Epileptic seizure within 48 hours prior to inclusion or anti-epileptic treatment * Patient in the intensive care unit who is intubated and on a ventilator * Pregnancy