The effect of xenon inhalation speed on cerebral blood flow obtained using the end-tidal method in xenon-enhanced CT.
OBJECTIVE
The purpose of this work is to show how variations in inhalation speed of xenon gas affect cerebral blood flow (CBF) values obtained using the end-tidal method on xenon-enhanced CT (Xe-CT). We tried to clarify whether arterial xenon concentration could keep up with end-tidal xenon concentration by evaluating the effect of xenon inhalation speed on calculated CBF values.


METHODS
The same subject underwent two or three consecutive Xe-CT examinations, varying xenon inhalation speed. The rate constants of applied inhalation speeds were 0.1-0.15 min-1 (low speed), 0.25-0.3 min-1 (middle speed), and 1-2 min-1 (high speed), respectively.


RESULTS
No significant difference was observed among the CBF values of the same subject obtained under different inhalation speeds.


CONCLUSIONS
End-tidal xenon can closely reflect arterial xenon under the customary method of xenon supply. The end-tidal method can provide reliable absolute CBF values, assuming actual CBF values are substantially unchanged regardless of the inhalation speed variation applied in this work.
Sase
S
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Anzai Medical Corporation, Tokyo, Japan.
D000280:Administration, Inhalation; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003287:Contrast Media; D006801:Humans; D008297:Male; D012016:Reference Values; D013990:Tidal Volume; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data; D014978:Xenon / Q000008:administration & dosage
D003287:Contrast Media; D014978:Xenon