Stable xenon CT-CBF study with measurement of end-tidal xenon concentration

Non-invasive methods with monitoring end-tidal stable xenon are described for estimating local cerebral blood flow (LCBF) and local partition coefficient (Lλ). 30 % of xenon was inhaled for 240 sec and exhaled for 160 sec during serial CT scannings. During the examination serial samplings of arterial blood and continuous monitoring of xenon were performed to determine build up range (A) and build up rate constant (K) of artery. Calculated A and K using the arterial sampling (As and Ka, respectively) were compared with the calculated A and K using the continuous monitoring of xenon (Ae and Ke, respectively) in 109 patients. (author)