Thornhill Scientific Inc.

Kamil Uludag

Joseph A Fisher

James Duffin

Olivia Sobczyk

David J Mikulis

Julien Poublanc

Ece Su Sayin

Jacob B Schulman

Deoxyhemoglobin contrast has been used to locate arteries based on the earlier blood oxygen-level dependent (BOLD) signal arrival time, higher BOLD signal strength, and shorter mean transit time. However, additional strategies of identifying arteries with oxygen modulation are required to improve the sensitivity and specificity of results. The present disclosure provides a method of distinguishing extravascular voxels from intravascular voxels based on the magnetic signal obtained from two hypoxic boluses having two different baselines. Intravascular voxels are responsive to changes in the baseline due to their high blood volume, while extravascular voxels are not affected by changes to the baseline. Amongst intravascular voxels, arteries can be distinguished from veins because the extraction fraction of the arterial blood is reduced during hypoxia, and therefore veins are less sensitive to changes in the baseline.

Identifying the vascularity of cerebral tissue in subjects using deoxyhemoglobin contrast

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Toronto, Canada

Kamil Uludag