Influence of Rheological Therapy on Regional Cerebral Blood Flow in Patients with Cerebrovascular Disease
Vascular diseases of the brain results in different neurologic and psychiatric symptoms depending on the location of blood flow reduction and on character of formation. Nowadays it is possible to measure the degree of ischemia in the brain with different techniques: Whereas Positron Emission Tomography allows estimation of regional cerebral blood flow and cerebral metabolism its application is limited to certain centers due the considerable costs and enormous technical suppositions. The stable Xenon technique — which uses the “cold” anesthetic Xenon gas — permits measurement of local blood flow in a three-dimensional way but is not applicable to out-patients, since it possesses anesthetic effects (depending on the concentration used). The Kety-Schmidt-technique with inhalation of nitrous oxide measures blood flow and metabolism of the total brain or one hemisphere respectively but does not produce regional data. Focal defects are overlooked. The nontraumatic Xenon 133-method allows repeated measurements of regional cerebral blood flow (rCBF) of both hemispheres. Since the method does not request any invasive procedure it can be used repeatedly on an outpatient basis. The technique involves the application of small amounts of Xenon 133, which are inhaled over a period of 60 sec, followed by 10 min of desaturation (with inhalation of room air). During this period 32 detectors, placed over both aspects of the skull, re-cord the activity from brain, bone,muscle etc. of the head. The correction of these raw curves results in calculation of flow data of the brain tissue itself. Different modes of calculation permit the estimation of several flow data, which represent the tissue perfusion of either the grey matter alone (F1, grey matter flow) or a mixture of both the grey and the white matter (initial slope index — ISI — and mean flow-MF).
KeywordsRegional Cerebral Blood Flow Cerebral Metabolism Local Blood Flow Focal Defect Verum Group
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