EVALUATION OF REGIONAL CEREBRAL BLOOD-FLOW IN ACUTE HEAD-INJURY BY STABLE XENON-ENHANCED COMPUTERIZED-TOMOGRAPHY

Measurement of regional cerebral blood flow (rCBF) in headinjured pati ents is considered useful for understanding the cerebral hemodynamics of brain trauma and for determining the optimal therapy. Most data thu s far obtained with Xe-133 clearance techniques have made only relativ e contribution, due to limitations of the Xe-133 method. More recently , is has become possible to measure rCBF by xenon-enhanced computerize d tomography (Xe-CT), which obviates most problems inherent to the Xe- 133 method. On the other hand, computational errors and concerns regar ding the safety of xenon inhalation have thwarted the clinical use of Xe-CT. Recent advances in CT technology, however, have largely elimina ted these problems. Xe-CT CBF measurements in severe head injury demon strate a good correlation between CBF values obtained with Xe-113 and Xe-CT. By consistently applying these studies in conjunction with conv entional CT, information on very early flow derangements (within 1 to 2 hours after injury) can be obtained, in relation to anatomical lesio ns. Preliminary data reveal higher incidences of global and focal isch aemia than found previously. Local ischaemia tends to evolve to hypere mia in the ensuing days.