Brief summary

The primary goal of neurocritical care is to prevent secondary brain injury, which worsens neurological outcomes. Because clinical monitoring is often insufficient due to the patient's condition and medical treatments, multimodal monitoring using biophysical, electrophysiological, and imaging data is essential. In patients with subarachnoid hemorrhage (SAH), the most frequent and severe complication is delayed cerebral ischemia, often linked to arterial vasospasm and potentially leading to infarction. Early diagnosis combines transcranial Doppler (TCD), sensitive to vasospasm, with perfusion CT (CTP), which measures cerebral perfusion; this approach guides therapy and improves prognosis. Ultrasound, especially when enhanced with contrast agents (CEUS), allows non-invasive, bedside, repeated visualization of cerebral blood flow and perfusion-even through the skull. Agents like SonoVue® help quantify perfusion using time-intensity curves. The study aims to assess whether cerebral perfusion measurements from the SYLVER device are equivalent to those from CTP in ICU or CCU patients.