Measurement of cerebral blood low by X-ray computed tomography with a short inhalation of low-dose stable xeno

A less invasive technique has developed for measurement and mapping of cerebral blood flow (CBF) and brain/blood partition coefficient (λ) by xenon computes tomography (Xe-CT). Six minutes inhalation of 30% xenon had no influence on electronencephalography in nomal adults, and head motion was seen in only 2.6% of clinical 310 cases. The cerebral xenon enhancement data were utilized in order to calculate CBF and CBF/λ ratio (k), using multivaluaboe analysis. This analysis method is a modified least-squares search by Koeppe, that dose nor use so called ”curve-fitting”. CBF and k values were calculated under unsaturation of brain with xenon. And λ was estimated as a ratio of CBF/k. In this analysis method, ”curve-fotting” was not needed, so this analysis method made it able to treat respiratpry endidal xenon data, which are inadequate to a exponential curve-fitting because of irregular respiration, with a linear interpolation method. A single to noise ratio of increment in Hounsfiled number of brain, should be as low as 30% xenon. But with smoothing of sampled data of intraserebral xenon, resonalble and reliable values of CBF and λ were obtained. And also high resolution between white matter and grey matter was obtained. Two dimensional Gauss function was used for smoothing. Also in clinical application, our new technique brought out many useful findings, these could not be obtained by X-ray CT or angiography alnoe, especially on ischemic cerebral vascullar disease.