Why is XeCT/CBF method superior to others?
The basis of XeCT/CBF is the Fick principle (1870) of a diffusible tracer (DT) as applied to the human brain in 1948 by Kety/Schmidt and refined by Kety in 1951 12,13,14. It has been validated against every known quantitative CBF method. CBF measured using DTs is a physiological measurement. Similar measurements with non-diffusible tracers (NDTs) are anatomical measurements claiming to be physiological measurements. Current attempts to quantify non-diffusible tracer studies will provide reasonable to excellent data in humans with a normal cerebrovascular (CV) system. In neurovascularly compromised patients, non-diffusible methods are destined to failure due to the following reasons: a) NDTs are highly dependent on the vascularization of the brain, or how it got there. DTs answer the question is it there?. NDTs are a snapshot in time (MTT and TTP < 10 seconds), where a DT measures 4-5 minutes of tissue enhancement. This is an extremely important consideration in patients with collateral
