And so how did the authors set out to demonstrate their hypotheses?

Um, so basically the authors conducted the, a retrospective study.

It is, uh, based, uh, on, uh, uh, it's quite a small number of patients.

And, uh, the hypothesis was that the perfusion, uh, uh, heterogeneity may be more important than the absolute cerebral blood flow in determining who develops a delayed cerebral ischemia.

They examined the, the measure of, uh, spatial heterogeneity on the CT perfusion by using the coefficient of variation of cerebral blood flow across the whole brain and within individual vascular territories, so a very, let me say, capillary evaluation of the physiology.

The protocol that they proposed is, uh, mainly driven by the CT perfusion, so basically it worked, uh, in this way.

The patients first underwent a baseline CT perfusion after the aneurysm treatment.

And tell us about the, um, cardiac output monitoring that they were using.