Commentary to brain-wide continuous functional ultrasound imaging for real-time monitoring of hemodynamics during ischemic stroke.

Functional ultrasound (FUS) has emerged as a novel imaging method to reliably assess relative cerebral blood volume (rCBV) and infer perfusion, with good spatiotemporal resolution. Brunner and colleagues provide what appears to be its first application to characterize peri-infarct spreading depolarizations (SDs) in experimental stroke through recording of transient hyperemic events. They also report incomplete overlap between acute perfusion deficits and subsequent infarct distribution, specifically noting a rostral expansion to involve penumbral territory from which propagating depolarizations had preferentially originated. This observation would not be straightforward using other methodologies. Other strengths and limitations of the study are considered.